JP2000193438A - Method and device for measuring 3-dimension form, and storage medium where 3-dimension form measuring program is stored - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove noises caused by multiple reflections. SOLUTION: An increase/decrease extracting process E4 wherein the change in increase/decrease of the space code in the same direction as the scanning direction of measurement light in an irradiation process E1 is extracted, and a multiple reflection judging process E5 wherein such a space code as the increase/decrease of the space code extracted in the increase/decrease extracting process E4 is decrease or increase which is a change reversal to pre-set increase or decrease is specified while the space code wherein the increase/decrease of that space code is reversal is judged to be a space code of multiple reflection, are provided. Further, following the multiple reflection judging process E5, a delete process E6 where a space code judged to be multiple reflection in the multiple reflection judging process is deleted, are provided. A distance calculating process E7 where, after a noise caused by multiple reflection is removed, a distance from the original point to the surface of an object to be measured on a coordinate system pre-set based on the space code calculated in the space code specifying processes E4-E6 and the position of light-reception element is calculated for each light-reception element, is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for measuring a three-dimensional shape and a storage medium storing a three-dimensional shape measurement program, and more particularly to a three-dimensional shape for accurately measuring the shape of an object to be measured. The present invention relates to a measurement method and a three-dimensional shape measurement device.

[0002]

2. Description of the Related Art Conventionally, in order to measure a three-dimensional shape, an irradiation angle of a laser beam and a C which receives a return beam of the laser beam are used.
The distance to the surface of the object to be measured is calculated based on the principle of triangulation based on the position of the light receiving element of the CD. For example, in Japanese Patent Application Laid-Open No. Hei 10-213423 filed by the same applicant, in order to obtain a spatial code, a spatial coded pattern is projected and imaged by the number of the patterns, and bit plane images of the captured image are sequentially superimposed. By combining, a spatially coded image is obtained. Then, the distance to the surface of the object to be measured is calculated from the pixel position where the space code is stored and the space code.

In the case of the light cutting method, the irradiation angle of the slit light is called an angle code or a space code. The space code irradiates the defined slit light, and the angle code of the slit light can be used as the space code.
Then, the distance to the object to be measured can be calculated from the angle code of the slit light and the pixel position that has received the slit light of the angle code.

[0004]

However, in the above-mentioned conventional example, there is a disadvantage that an incorrect angle code is recorded due to multiple reflections on a blind spot which is a place where illumination is not applied. Then, noise is generated, and a shape that should not exist appears. Since the multiple reflection to the blind spot area occurs near the actual shape, there is an inconvenience that removal is very difficult. In other words, noise removal by multiple reflections can be removed based on distance information if the noise is located far away from the actual shape. It is difficult to remove by hand.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method and an apparatus for measuring a three-dimensional shape capable of improving the disadvantages of the prior art and removing noise due to multiple reflections.

[0006]

Therefore, according to the present invention, there is provided an irradiation step of irradiating measurement light corresponding to a space code for dividing a space including an object to be measured, and an irradiation angle of the measurement light irradiated in this irradiation step. A light receiving step of receiving the measurement light by each light receiving element two-dimensionally arranged on a light receiving plane forming a predetermined angle with respect to the light receiving element, and receiving each light based on an order of the measurement light received in the light receiving step. A space code processing step of calculating a space code for each position corresponding to the element, and measurement from an origin in a predetermined coordinate system based on the space code calculated in the space code processing step and the position of the light receiving element Calculating a distance to the surface of the object for each light receiving element. In addition, in the space code processing step, an increase / decrease extraction step of extracting an increase / decrease change of the space code in the same direction as the scanning direction of the measurement light in the irradiation step, and an increase / decrease of the space code extracted in the increase / decrease extraction step. Identify a spatial code that is monotonically decreasing or monotonically increasing, which is a change in the opposite direction to a predetermined monotonically increasing or monotonically decreasing space code, and a spatial code obtained by multi-reflecting a spatial code in which the increase or decrease of the spatial code is reversed. And a multiple reflection determining step of determining that This aims to achieve the above-mentioned object.

[0007] In the irradiation step, a slit light, a spot light, each of which defines an angle code, and a plurality of time-series space coded pattern lights defined by a binary code are irradiated as measurement light. In the light receiving process, for example, an area type CCD
The measurement light is received using a sensor. In the spatial code processing step, according to the type of the measurement light, for example, a bit plane is generated in the case of a time-series space coded pattern, and the brightness value is maximized based on the order of the bits, and in the case of slit light. A spatially coded image is generated based on the order of the slit light. Then, in the distance calculation step,
The distance to the object to be measured is calculated according to the principle of triangulation according to the angle of the measurement light and the pixel position of the spatially coded image. At this time, for example, the focus position of the light reception may be set as the origin, or one point of a space including the measurement target may be set as the origin by performing calibration.

In the space code processing step, in the increase / decrease extraction step, a change in the increase / decrease of the space code in the same direction as the scanning direction of the measurement light in the irradiation step is extracted. Then, if the space code is increased in the scanning direction of the measurement light, an increase tendency of the space code is usually observed. On the other hand, when multiple reflections occur, the traveling direction of the slit light is reversed and travels in the opposite direction to the scanning direction, so that the increasing tendency of the space code is determined to be reversed. Accordingly, in the multiple reflection determination step, the increase or decrease of the space code extracted in the increase or decrease extraction step specifies a space code in which the increase or decrease is a decrease or increase that is a change opposite to a predetermined increase or decrease, and The space code in which the increase / decrease of the space code is reversed is determined as a space code due to multiple reflection. As a result, even multiple reflections occurring in the blind spot are reliably extracted based on changes in the increase or decrease of the space code.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a flowchart showing the configuration of the three-dimensional shape measuring method according to the present embodiment. As shown in FIG. 1, the three-dimensional measurement method according to the present embodiment includes an irradiation step E1 of irradiating measurement light corresponding to a space code that divides a space including an object to be measured, and a measurement irradiated in the irradiation step E1. A light receiving step E2 of receiving the measurement light by each of the light receiving elements arranged two-dimensionally on a light receiving plane at a predetermined angle with respect to the light irradiation angle; and a light receiving step E2 of the measurement light received in the light receiving step E2. A space code specifying step E3 of calculating a space code for each position corresponding to each light receiving element based on the order.

In this embodiment, furthermore, an increase / decrease extraction step E4 for extracting an increase / decrease change of the space code in the same direction as the scanning direction of the measurement light in the irradiation step E1, and a space code extracted in the increase / decrease extraction step E4 The increase / decrease of the predetermined increase or decrease is a change in the opposite direction to the decrease or increase in the space code, and the space code in which the increase / decrease of the space code is reversed is referred to as the space code by multiple reflection. And a multiple reflection determination step E5 for determination. Further, the example shown in FIG. 1 includes, following the multiple reflection determination step E5, a deletion step E6 for deleting the spatial code determined to be multiple reflection by the multiple reflection determination step. After removing noise due to multiple reflections, the distance from the origin in the predetermined coordinate system to the surface of the measurement object based on the space code calculated in the space code specifying steps E4 to E6 and the position of the light receiving element. Is calculated for each light receiving element, and a distance image data output step E8 for outputting the distance image data calculated in the distance calculation step.

In step E6, the spatial code due to multiple reflection is deleted, but depending on the embodiment,
An error flag adding step E6 for adding an error flag to the space code determined to be multiple reflection in the multiple reflection determining step E5 may be provided. In this case, it is preferable to perform processing such as changing the display color of the distance data based on the space code to which the error flag has been added in the distance image data from other parts.

In the following, in order to explain the change in the increase / decrease of the space code due to multiple reflection, first, a method of calculating the distance to the surface of the object to be measured using the space code will be described.

FIG. 2 is an explanatory diagram showing the principle of distance measurement using a space code. In the example shown in FIG.
The irradiation means for realizing 1 includes a laser light source 22 and a galvanomirror 23. The camera 3 is used in the light receiving step E2. Laser light source 22, Galvano mirror 2
As shown in FIG. 2, the camera 3 and the camera 3 are on a floor surface (horizontal surface).
Are located on the same plane which is horizontal with respect to. Also,
The galvanometer mirror 23 is disposed at a distance of l from the optical axis of the camera 3 and rotates around a vertical direction (parallel to the slit light R) with respect to the horizontal scanning line of the light receiving element 31 of the camera 3. . With this arrangement, it is possible to move the slit light R in the parallel direction along the horizontal scanning line of the light receiving element 31 and allow the light receiving element 31 of the camera 3 to receive the light.

The space code is, for example, a value that is increased at every fixed angle in the scanning direction of the galvano scanner 23 corresponding to the value of θ shown in FIG. Projection angle θ for any pixel
And the angle α of the slit light R position from the camera 3 is specified from the x component of the position coordinates of each pixel (FIG. 2).
Is a right angle.) Further, since the separation distance l between the camera 3 and the galvanometer mirror 23 is a known value, it can be obtained from, for example, the distance h = l · sin θ / sin (α + θ). The value of θ is determined by the scanning angle of the galvano scanner, and the value of α is determined by the position of the light receiving element that has received the light. Therefore, from these two angles and the predetermined distance l, the position of the position irradiated with the measurement light is determined. The distance h to the surface of the measurement object can be calculated.

FIGS. 3 to 5 are explanatory diagrams showing the relationship between the measurement light and the space code. As shown in FIG. 3A, when the measurement object S is a plane and the slit light is sequentially scanned on the measurement object from the left side in the figure, the initial angle θ1
The space can be divided by angle codes from to .theta.n. In the example shown in FIG. 3, the scanning is performed from the left side to the right side in the figure, and the space code is increased in accordance with the scanning.
The relationship between the horizontal pixel coordinates and the space code in 2 is as shown in FIG. As shown in FIG. 3B, the value of the space code increases as the horizontal pixel coordinates increase. In FIG. 3 (C), the space code is represented by shading,
The space code shown in black is the smallest, and the space code shown in white is the largest.

In the example shown in FIG. 4, a cylindrical object S2 exists on the camera 3 side of the measuring object S1. In the figure,
1 to 9 are the values of the space code in which θ is omitted. 4
As shown in (A), the slit light having the angle codes θ1 to θ5 is applied to a flat measurement target S1. However, the slit light having the following angle codes θ6 and θ7 is applied to the small object S2. Then, in the continuation of the horizontal pixel coordinates in the scanning direction, the angle code increases from θ3 to θ6.
On the other hand, after increasing to θ6, the angle codes θ4 and θ5 passing through the back side of the small object are imaged. Subsequently, the slit light having the angle codes θ8 and θ9 is radiated to the planar measurement object S1. At this time, the area between the angle codes θ5 and θ8 is a blind spot due to the small object S2, and no angle code is recorded. However, as shown in FIG. 4, the angle code (space code) tends to increase in the scanning direction when discontinuous portions such as a change from the angle code θ3 to θ6 or a change from θ7 to θ4 are removed. . As shown in FIGS. 4C and 4D, even if the surface of the measuring object S is inclined, the increasing tendency of the angle code does not change, but only the inclination changes.

FIG. 5 shows an example in which multiple reflection occurs. In the example shown in FIG. 5, the angle codes θ8 and θ9 are
Multiple reflection occurs on the wall surface S4. In the multiple reflection, even when the irradiation is increased to θ8 and θ9, this relationship is reversed by reflection, and the space code continuously decreases to θ9 and θ8 as shown in FIG. I do. FIG. 5B shows the relationship between the space code and the horizontal pixel coordinates at this time.
Shown in The portion indicated by reference numeral 4a monotonically increases.
On the other hand, the portion indicated by reference numeral 4c is a blind spot, and the space code is 0. In the region where multiple reflections occur, reference numeral 4b
As shown by, the spatial code decreases continuously.

As described above, in the three-dimensional measuring device for generating a space-coded image, the angle code is monotonous in one direction of the image during measurement except for some exceptions (small objects floating in space). Increase (or monotonically decrease). When multiple reflection occurs and a code is recorded in a place different from a place where light is directly applied, this tendency of monotone increase (decrease) is broken.
Further, during multiple reflections caused by temporary reflection (single reflection), the code change monotonically decreases. Therefore, it is possible to remove noise due to multiple reflection by examining the tendency of the code to increase (decrease) along the horizontal scanning line from the output spatially coded image.

Therefore, the increase / decrease extraction step E4 shown in FIG. 1 extracts the change of the increase / decrease of the space code in the same direction as the scanning direction of the measurement light in the irradiation step E1, and the multiple reflection judgment step E5 determines the increase / decrease extraction step E4. When a spatial code whose decrease or increase is a change opposite to a predetermined increase or decrease in the spatial code extracted in is specified, the spatial code by multiple reflection indicated by reference numeral 4b in FIG. Can be identified.

FIG. 6 is a block diagram showing a configuration of a three-dimensional shape measuring apparatus suitable for implementing the three-dimensional shape measuring method according to the present embodiment. As shown in FIG. 6, the three-dimensional shape measuring apparatus according to the present embodiment includes an irradiation unit 2 that irradiates measurement light corresponding to a space code that divides a space including a measurement target,
A light receiving means 3 having light receiving elements arranged two-dimensionally on a light receiving plane at a predetermined angle with respect to the irradiation angle of the measuring light irradiated by the irradiation means 2; and each light receiving element of the light receiving means 3 And a space code processing means 4 for calculating a space code for each position corresponding to each light receiving element based on the order of measurement light received by the light receiving element.

The measuring apparatus further includes a space code storage means 42 for storing the space code calculated by the space code processing means 4 at a pixel position corresponding to each light receiving element.
And calculating the distance from the origin in the predetermined coordinate system to each surface of the measurement object for each light receiving element based on each pixel position of the space code storage means 42 and the space code stored in the pixel. And distance calculating means 100 for calculating the distance.

Further, the space code processing means 4 includes an increase / decrease extraction unit for extracting a change in increase / decrease of the space code in the same direction as the scanning direction of the measurement light by the irradiation means 2 from the space code image stored in the space code storage means 42. 4G and the space code extracted by the increase / decrease extraction unit 4G, the space code whose decrease or increase is a change opposite to the predetermined increase or decrease is specified, and the increase / decrease of the space code is specified. The multi-reflection determination unit 4H that determines the space code turned in the opposite direction as a space code by multiple reflection is provided.

Of the spatial code processing means, the increase / decrease extracting section 4G and the multiple reflection determining section 4H can be realized by using an arithmetic device such as a computer. in this case,
The arithmetic unit includes storage means for storing a three-dimensional measurement program, a CPU which functions as an unmeasurable point extracting unit 4B by executing the program, and a RAM which is a main storage device of the CPU. . The three-dimensional measurement program includes, as commands for operating the arithmetic device, an increase / decrease extraction command for extracting a change in increase / decrease of the space code in the same direction as the scanning direction of the measurement light irradiated by the irradiation device, and an increase / decrease extraction command. The increase or decrease of the space code extracted in response to the monotone decrease or monotone decrease is a change in the opposite direction to the predetermined monotone increase or monotone decrease, and the space code that has become the monotone decrease or monotone increase is specified, and the increase or decrease of the space code is in the opposite direction. And a multiple reflection determination command for determining the resulting spatial code as a spatial code by multiple reflection. Thereby, the configuration shown in FIG. 6 is realized, and the processing shown in FIG. 1 is performed by using the configuration shown in FIG.

[0024]

Next, an embodiment of a three-dimensional shape measuring process will be described with reference to the drawings. <Calibration> FIGS. 7 to 9 show examples of the configuration of the three-dimensional shape measuring apparatus. As shown in FIG. 2, the distance to the object to be measured can be calculated from the individual irradiation angles and the pixel positions of the light receiving elements. However, in practice, it is difficult to adjust the angle of view of the camera and the adjustment at the time of installation. In the present embodiment, the relationship between the spatial code and the pixel position is calibrated for reasons such as the property and the value in the coordinate system including the measurement object is easy to handle.

Generally, an imaged screen is detected by a planar CCD image sensor. , The camera coordinate system is Xc-
It is obtained by a two-dimensional coordinate system of Yc. When the relationship between the object coordinate system and the camera coordinate system is represented by a homogeneous coordinate system expression, it is represented by the following equation (1). Here, the matrix C for converting the object coordinate system into the camera coordinate system is called a camera parameter.

[0026]

(Equation 1)

On the other hand, since the projector obtains displacement in one-dimensional direction, the obtained coordinate system is only one-dimensional Xp. When the relationship between the projector coordinate system and the object coordinate system is represented by a homogeneous coordinate system expression, it is represented by the following equation (2).
Here, a matrix P for transforming the object coordinate system into the projector coordinate system is called a projector parameter.

[0028]

(Equation 2)

By developing these parameters and arranging them simultaneously, the following equations (3), (4) and (5) are obtained.

[0030]

(Equation 3)

Therefore, if an inverse matrix exists in the matrix Q, the object coordinate system V = (X, Y, Z) can be obtained from the camera coordinate system (Xc, Yc) and the projector coordinate system Xp. When the three-dimensional shape is measured by each of the above-described methods, it is necessary to obtain the camera parameters and the projector parameters in advance in order to obtain the matrix Q.

First, a light and dark image of the reference cube B is fetched by a CCD camera and a coded image by a space coding method by a slit projector. Then, the bright and dark images are binarized to take out the index portion, and the intersections obtained by virtually connecting the opposing indices in the plane of each cube and obtained in a grid shape are extracted as reference points (Xi, Yi, Zi). .

When calculating the camera parameters, the position coordinates of the reference point (known) on the object coordinate system and the pixel positions on the image sensor of the CCD camera on the picked-up image (position coordinates on the camera coordinate system) Xci, Yci)) are stored in pairs.

The position coordinates (X) of the reference point on the object coordinate system
i, Yi, Zi) and position coordinates (Xci, Yc) on the camera coordinate system.
i), the following equations (6) and (7) obtained from the above equations (3) and (4) hold.

[0035]

(Equation 4)

In each of the equations (6) and (7), C11... C21.
To find a total of 12 unknowns of C34, it is necessary to detect points on the camera coordinate system for at least six or more reference points that are not on the same plane. The unknown can be obtained by the least square method.

FIG. 7 shows an example of a three-dimensional measuring device and a calibration device. The three-dimensional shape measuring apparatus includes a projector 202 as an irradiation mechanism that irradiates irradiation light with position coordinates in a certain one-dimensional direction to the measurement target, and a camera that captures the measurement target irradiated with the irradiation light 3 and an image processing board 201 for calculating three-dimensional image data of the object to be measured from an image captured by the camera 3.

The projector 202 is capable of irradiating a stripe-shaped pattern light at a different pitch.
Operation control such as designation of irradiation timing and pattern light pitch is performed by the host computer 200. Also,
Instead of the pattern light, slit light may be applied. The projector coordinate system, which is a one-dimensional coordinate system, is formed in the direction in which the stripes are arranged (the direction perpendicular to the pattern light).

The CCD camera 3 has a light receiving element for outputting a luminance signal according to the luminance of the received light. This light receiving element is a pixel arranged in a plane. A camera coordinate system, which is a two-dimensional coordinate system, is formed corresponding to the plane of the CCD image sensor, and the position of each pixel corresponds to the position coordinates of the coordinate system.

The image processing board 201 includes the projector 2
02 and the CCD camera 3 are synchronized, and three-dimensional shape data is calculated based on the output of the CCD camera 3.

Next, a calibration device of the three-dimensional shape measuring device will be described. The calibration device includes a calibration two-dimensional gauge 202 having a plurality of indices 222 in a known arrangement on a smooth plane 221, and the gauge 202 is attached to the plane 221.
A uniaxial numerical control table 230 that is movably held in a direction perpendicular to the axis, and a uniaxial numerical control controller 240 that is provided in the uniaxial numerical control table 230 and that serves as adjusting means for adjusting the amount of movement of the calibration two-dimensional gauge 202. Have.

As shown in FIG. 7, the calibration two-dimensional gauge 202 has a plane 221 of a square.
1 is held in the uniaxial numerical control table 230 so as to face the CCD camera 3 and the projector 202.
Then, the optical axis of the objective lens of the CCD camera 3 and one plane 2
The normal to 21 is parallel. That is, thereby, the pattern light is emitted from the projector 202 to the one plane 221, the CCD camera 3 can capture a bright and dark image on the one plane 221, and the host computer 200
Three-dimensional coordinate data described later can be obtained via the image processing board 201.

The object coordinate system, which is a three-dimensional coordinate system, is set with reference to the calibration two-dimensional gauge 202. That is, in the calibration two-dimensional gauge 202 at the position shown in FIG. 7 (this position is assumed to be the current position), as shown in FIG. The origin is set horizontally rightward, and the Y-axis of the coordinate system is set vertically downward with the same angle of one plane 21 as the origin. Further, as shown in FIG. 8B, the Z axis of the coordinate system is
Are set to the opposite side to the CCD camera 3 along the normal direction of the one plane 221 with the same angle as the origin.
In this embodiment, the distance from the origin of the object coordinate system is calculated based on the space code and the pixel position.

Further, one plane 221 of the two-dimensional calibration gauge 202 is colored white, and an index 222 which is a black point for determining the reference point 23 is attached thereon. Index 222
As shown in FIG. 8A, five are arranged at equal pitch p on four sides of a square having each side parallel to the X-axis and Y-axis. The indices on the sides facing each other correspond to the indices on the other side, respectively, and as shown by the dotted line in FIG. Are connected by a straight line parallel to. The intersection of each straight line connecting the corresponding indices is the reference point 223. These reference points 223
5 × 5 = 25 cells are developed in a grid on one plane 21. Each index 21 is located on a known position coordinate in the object coordinate system described above, and accordingly, the position coordinate of each reference point 23 is also known.

The one-axis numerical control table 230 includes a holding member 231 of the calibration two-dimensional gauge 202 and a
The ball screw 32 that feeds the holding member 31 in the axial direction, and a stepping motor 33 that drives the ball screw 32 under numerical control by the single-axis numerical controller 4 are provided.

The one-axis numerical controller 240 receives a numerical input of the feed amount in the Z direction from the host computer 200, drives and controls the stepping motor 233 with a corresponding drive amount, and controls the two-dimensional It can be positioned at any position in the direction. At the time of calibration, the one-axis numerical control table 230 is usually set so that the feed direction of the calibration two-dimensional gauge 202 is parallel to the optical axis of the objective lens of the CCD camera 3, and the calibration two-dimensional gauge 202 is moved in the Z direction. Is sent four times from the current position with a feed amount equal to the pitch p of the reference point 223.

The host computer 200 controls the operation of the three-dimensional shape measuring device and the calibrating device and calculates the measurement information. The operation of the automatic calibration system of the three-dimensional shape measuring apparatus shown in FIG.
This is performed by a program input in advance at 00.

FIG. 9 is a flowchart showing the operation of the present embodiment. Hereinafter, a calibration operation of the three-dimensional shape measuring apparatus performed prior to the three-dimensional shape measurement of the present embodiment will be described based on this.

The variable step stored in the host computer 200 is initialized to 0 (step S1).

Then, the laser light output from the projector 202 of the three-dimensional shape measuring apparatus is continuously projected, and the image of each index attached to one plane of the two-dimensional calibration gauge 202 is captured by the CCD camera 3. Obtain light and dark images. Thereby, the host computer 200 sets the camera coordinate system Xc-Yc as a two-dimensional coordinate system in the storage area (step S2).

Next, a gray code pattern (pattern light on a stripe) is sequentially emitted from the projector 202 and a spatially coded image is captured by the CCD camera 3.
The host computer 200 obtains a space code from the captured image, and thereby sets a projector coordinate system Xp as a one-dimensional coordinate system in the storage area (step S3).

The captured light-dark image is binarized, and the center-of-gravity pixel (center) of each circular index 222 is obtained (step S4).

In the host computer 200, a virtual intersection point of a straight line connecting the respective indices 22 facing each other is obtained by calculation as the actual coordinate reference point 23 for calibration (step S).
5).

Then, in the storage area of the host computer, the position coordinates (Xc-Yc) of each reference point 223 on the camera coordinate system and the position coordinates Xp of the projector coordinate shape are stored as data corresponding to each other (step S).
6).

In the host computer 200, the steps are incremented (step S7), and the calibration two-dimensional gauge 202 is moved in the Z direction by a distance of the pitch p (step S8).

It is confirmed whether or not the imaging of the calibration two-dimensional gauge 202 has been performed five times, that is, whether or not the movement in the Z-axis direction has been performed four times (step S9). The operation of step S8 is repeated. If it has reached, the camera parameters and the projector parameters are obtained based on the stored data to calculate the system parameters (step S10). Then, the calibration is completed.

In this embodiment, a three-dimensional shape measuring apparatus 1 for measuring a three-dimensional shape based on a spatial coding method is used.
Although the example in which the calibration work is performed for 00 is shown, the present invention is also effective for a measuring device that measures a three-dimensional shape by scanning one slit light or a measuring device based on another method.

As described above, the relationship between the pixel position and the space code is calibrated in advance by using the calibration device shown in FIG.
Then, in the actual measurement, the distance from the origin in the object coordinate system can be calculated from the space code and the pixel position.

<Measurement> In order to obtain a space-coded image, there are a light cutting method using slit light, a pattern light projection method using a time-series space coding pattern (gray coding pattern), and the like. Regarding the pattern light projection method, in the projection of the pattern light, holes are unlikely to occur other than the blind spot area and the abnormality of the light receiving element itself. On the other hand, in the calculation processing of the spatially coded image by the slit light projection, a hole may be generated. Therefore, an example of the shape measurement of the measurement object will be described below using the light section method as an example.

FIG. 10 is a block diagram of this embodiment.
Here, an irradiation unit 2 that scans the measurement object S with the slit light R, a camera 3 that images the slit light R that moves by scanning from a direction different from the irradiation unit 2 a plurality of times, and a plurality of captured images And a space code processing means 4 for calculating a space code (angle code) from the data.

The three-dimensional shape measuring apparatus outputs the three-dimensional image data calculated by the space code processing means 4 to the computer 100 connected via the digital I / O board 102, as shown in the figure. Meanwhile, computer 1
00 calculates a three-dimensional shape based on the angle coded image (space coded image) from the space code processing means 4 and its pixel position. In this calculation, a distance in the object coordinate system is calculated using camera parameters and the like calculated using the above-described calibration device.

The irradiating means 2 includes a laser light source 22 for irradiating one slit-shaped laser beam (hereinafter, referred to as a slit beam R) driven by a laser driver 21, and an illuminating slit beam R for an object to be measured. A galvanometer mirror 23 that reflects to the S side, and a galvanometer scanner 2 that rotates the galvanometer mirror 23 to scan the slit light R with respect to the measurement target S.
4, a scanner driver 25 for controlling the drive of the galvano scanner 24, and a projection angle command generation circuit 26 for outputting a projection angle command to the scanner driver 25 based on the angle signal from the space code processing means 4.

The slit light R emitted from the laser light source 22 is a rod-shaped light along the vertical direction (up and down direction in FIG. 10) with respect to the floor surface at the time of measurement. The object S to be measured is scanned by moving in the vertical direction. Also, the slit light R
Is set in advance so as to be perpendicular to the horizontal scanning line of the light receiving element 31 of the camera 3.

The projection angle signal is output from the memory address creation circuit 46 of the space code processing means 4 to the projection angle command creation circuit 26, and the galvano scanner 2 is
4 is performed.

The laser light source 22, the galvanometer mirror 2
As shown in FIG. 2, the camera 3 and the camera 3 are on a floor surface (horizontal surface).
Are located on the same plane which is horizontal with respect to. Then, the galvanomirror 23 rotates around a vertical direction (a direction parallel to the slit light R) with respect to the horizontal scanning line of the light receiving element 31 of the camera 3. With this arrangement, it is possible to move the slit light R in the parallel direction along the horizontal scanning line of the light receiving element 31 and allow the light receiving element 31 of the camera 3 to receive the light.

In the present embodiment, the light receiving element 31 is provided with 256 pixels in the horizontal scanning line direction, and 243 such horizontal scanning lines, and a total of 256 × 243 pixels are regularly arranged. I have. The output of the luminance signal from each pixel is performed for each horizontal scanning line in the arrangement order in the horizontal scanning line direction. At this time, a period during which the luminance signal of one horizontal scanning line is output is called an output period, and a period between an output period during which no output is performed and an output period is called a blanking period. Further, each pixel on one horizontal scanning line outputs in the arrangement order during the output period. Then, outputs from all the pixels are sent to the space code processing means 4 as video signals. As described above, in this embodiment, the camera 3 has the same space code as the number of pixels in the horizontal scanning line direction.

The camera 3 captures an image by dividing one scan of the slit light R by the number of pixels (256) on the scanning line. For this reason, the scanning range angle of the galvano scanner 24 is divided into 256, and synchronization is achieved by a horizontal and vertical synchronization signal output from a synchronization circuit 43 of the space code processing unit 4 described later in order to perform imaging at each angle.

FIG. 1 is a block diagram of the spatial code processing means 4.
It is shown in FIG. The space code processing means 4 includes a light receiving element 31
A peak detector 5 for detecting and specifying the maximum value of the luminance output from each pixel for each scanning line,
In response to the detection, the pixel position detector 8 detects and specifies the position on the scanning line for the pixel that outputs the maximum luminance, and the luminance memory 41 having a recording area of the luminance individually corresponding to each pixel of the light receiving element 31. Based on the luminance detected by the peak detection unit 5 and the position of the pixel detected by the pixel position detection unit 8, the magnitude of the recording luminance recorded in the recording area of the corresponding pixel in the luminance memory 41 is compared. A second comparing circuit 6 as a comparing section, and a third selecting circuit 7 as a first updating section for updating the recording luminance of the luminance memory 41 to the value of the detected luminance when the detected luminance is larger than the recording luminance. And an angle coding memory 42 having a recording area of a projection angle individually corresponding to each pixel.

Further, the spatial code processing means 4 comprises a synchronizing circuit 43 for synchronizing the camera 3 in the horizontal and vertical directions, an A / D conversion circuit 44 for quantizing the luminance signal of the video signal from the camera 3, and a luminance memory. 41 and angle coded memory 42
And a memory address creation circuit 46 for creating an address.

The memory address generating circuit 46 counts the horizontal synchronizing signal from the synchronizing circuit 43 to determine the horizontal scanning line number (the number of the horizontal scanning line from the end) at which the currently output pixel of the light receiving element 31 is located. Indicates that the output is being performed. Hereinafter, this is referred to as a vertical address y).

Further, the memory address creation circuit 46
Horizontal drive frequency (number of pixels in a scanning line 768, 14.318)
MHz) is divided by 3 (to make the number of pixels in the scanning line 256), and the position of the pixel currently being output from the light receiving element 31 on the horizontal scanning line (the number of pixels from the end on the horizontal scanning line) Indicates whether the horizontal address x is output.

The vertical synchronizing signal from the synchronizing circuit 43 is counted, and a projection angle signal is generated and output to the irradiation means 2. Further, in the memory address creation circuit 46, a clear signal of a temporary brightness memory 51 of the peak detection unit 5 and a temporary location memory 81 of the pixel position detection unit 8, which will be described later, is created for each output of one horizontal scanning line by a horizontal synchronization signal. And output.

The luminance signal quantized by the A / D conversion circuit 44 is output to the peak detector 5. The peak detection unit 5 includes a temporary luminance memory 51 for recording only the luminance at the maximum level on one scanning line, and a signal level of a luminance signal quantized by the A / D exchange circuit 44 (hereinafter simply referred to as “luminance”). ") And the maximum luminance memory 5 in the scanning line.
A first comparison circuit 53 that compares the luminance recorded with the first and outputs which luminance is higher, and selects the higher luminance based on the output of the first comparison circuit 53;
And a first selection circuit 54 for updating the recording luminance in the temporary luminance memory 51.

The temporary luminance memory 51 only needs to record a luminance signal for one pixel, and its storage capacity is luminance resolution × 1 (8 bits). The contents of the temporary luminance memory 51 are cleared to 0 during each horizontal blanking period (for each horizontal scanning line).

With the above configuration, the peak detector 5 detects and records the maximum level of the luminance signal for each scanning line.

When the maximum luminance on one scanning line is detected by the peak detecting section 5, the pixel position detecting section 8 simultaneously outputs the horizontal address x of the pixel outputting the maximum luminance.
Is detected. The pixel position detection unit 8 includes a temporary position memory 81 that records only the horizontal address x of the pixel that outputs the maximum luminance on one scanning line, and a horizontal address corresponding to each pixel sequentially output from the memory address generation circuit 46. x, the first comparison circuit 53 of the peak detection unit 5 described above.
And a second selection circuit 82 that overwrites the temporary position memory 81 with the horizontal address x of the pixel that outputs the maximum luminance selected by the output.

The above-mentioned temporary position memory 81 stores 25
It is enough to be able to record which of the six pixels it is, so its storage capacity is 256 × 1 (8 bits). The contents of the temporary position memory 81 are cleared to 0 during each horizontal blanking period (for each horizontal scanning line).

With the above configuration, the pixel position detector 8 outputs the horizontal address x of the pixel that outputs the maximum luminance for each scanning line.
Are detected and recorded.

Each temporary luminance memory 51 has a gate 91
Via the second comparison circuit 6 and the third selection circuit 7
The recording luminance in the temporary luminance memory 51 is output to these when the gate 91 is closed. on the other hand,
The temporary position memory 81 is connected to the luminance memory 42 and the angle coding memory 42 via a gate 92, and when the gate 92 is closed, the horizontal address x in the temporary position memory 81 is output to them.

Each of these gates 91 and 92 is connected to the memory address generating circuit 46 and receives the output of the horizontal synchronizing signal of the light receiving element 31. These gates 91 and 92 are normally open, and are closed when it is input from the horizontal synchronization signal that the light receiving element 31 is in the flyback period.

The gates 91 and 92 are connected to the light receiving element 3
1 constitutes an output synchronizing unit 9 for simultaneously outputting the recorded contents of the temporary luminance memory 51 and the temporary position memory 81 during the flyback period.

Next, the luminance memory 41 will be described.
In the luminance memory 41, a recording area of luminance corresponding to each pixel of the light receiving element 31 is formed (see FIG. 13). In each recording area of the luminance memory 41, a luminance set in advance to a value smaller than 0 to a value smaller than the luminance of the normal slit light is recorded.

As described above, when the gates 91 and 92 are closed, the maximum luminance is output from the temporary luminance memory 51 to the second comparison circuit 6, and the horizontal address x is output from the temporary position memory 81 to the luminance memory 41. Is done. The current vertical address y is always output from the memory address creation circuit 46 to the luminance memory 41.

As a result, the pixel outputting the maximum luminance from the horizontal address x and the vertical address y to the luminance memory 41 is identified as one of the pixels of the light receiving element 31. The recording luminance is output to the second comparison circuit 6 from the recording area to be recorded.

In the second comparison circuit 6, the temporary luminance memory 5
The luminance from 1 is compared with the luminance already recorded in the luminance memory 41, and which is higher is output. The third selection circuit 7 receives the output of the second comparison circuit 6 and, when the luminance from the temporary luminance memory 51 is high, the luminance memory 41
Is updated to the luminance of the temporary luminance memory 51; otherwise, the recording luminance of the luminance memory 41 is maintained as it is.

Next, the angle encoding memory 42 will be described. The angle coded memory 42 stores the light receiving element 31
The recording area of the projection angle θ of the slit light R (which is synonymous with the rotation angle of the galvanomirror 23 in this case) θ corresponding to each pixel is provided.

The angle encoding memory 42 has
A fourth selection circuit 45 as a second updating unit for updating the projection angle θ of each recording area is also provided. The fourth selection circuit 45 is connected to the second comparison circuit 6 that operates when the gate 91 is closed, and at the same time, emits a light emission angle signal indicating the current light emission angle θ from the memory address creation circuit 46. Is entered.

On the other hand, the current vertical address y is always input from the memory address creation circuit 46 to the angle encoding memory 42, and the maximum luminance is output from the temporary position memory 81 by closing the gate 92. The horizontal address x of the pixel is input. As a result, the pixel which has output the maximum luminance from the horizontal address x and the vertical address y to the angle coding memory 42 is identified as one of the pixels of the light receiving element 31, and the fourth selection is performed. The input state by the circuit 45 is awaited.

The fourth selection circuit 45 includes a second comparison circuit 6
When the luminance of the temporary luminance memory 51 is higher than the luminance of the temporary luminance memory 51 and the luminance of the luminance memory 41, the light projection angle θ from the memory address creation circuit 46 is recorded in the corresponding recording area. However, if the luminance memory 41 outputs that the luminance is high, the update is not performed. As described above, since the third and fourth selection circuits 7 and 45 are both updated by the output of the second comparison circuit 6, when the luminance of the temporary luminance memory 51 is updated with respect to the luminance memory 41, Only, the projection angle θ to the angle coding memory 42
(Update if already recorded) is performed.

Here, the recording of the luminance memory 41 and the angle coding memory 42 are cleared to 0 at the start of measurement.

FIG. 12A shows the slit light R imaged on the light receiving element 31. At this time, the scanning range by the irradiation mechanism is divided into 256, and imaging is performed for each of the divided ranges.
It will be represented by the number 56. FIG. 12B shows the luminance level detected from each pixel along the horizontal scanning line of scanning line number 1. According to this figure, a maximum luminance level is observed at a position x0 in the horizontal scanning line direction, and this can be regarded as slit light.

When the functions of the above components are combined, the three-dimensional shape measuring apparatus 10 regards the pixel which has detected the maximum luminance on the horizontal scanning line during the output period as the irradiation position of the slit light, and sets the maximum luminance for each scanning line. Then, the horizontal address x of the pixel in which is detected is obtained, and the projection angle of the irradiated slit light is obtained, thereby completing the angle encoding memory 42. With this, when the projection angle is obtained for each pixel address, the camera 3 can determine the projection angle from the measurement target S imaged at each address.
, And the computer 100 measures the three-dimensional shape.

For this reason, first, for the horizontal scanning line currently in the output period by the peak detecting section 5, the maximum luminance out of the luminances output from the pixels on the horizontal scanning line is specified, and is stored in the temporary luminance memory 51. Be recorded. In addition, during the output period, the horizontal address x of the pixel that outputs the maximum luminance is specified by the pixel position detection unit 8 and is recorded in the temporary position memory 81.

The maximum luminance and the horizontal address x recorded in each of the memories 51 and 81 are held until the output period ends and a blanking period is reached. It is output to 41 or the angle coding memory 42 side. As described above, since the luminance and the horizontal address x are suspended during the output period, the luminance determined to be the maximum in the course of the processing is processed on the downstream side (to the luminance memory 41 and the angle encoding memory 42). Record)
Is not done.

Then, based on these outputs and the output of the vertical address y and the light projection angle signal by the memory address creation circuit 46, the brightness of the address specified by the second comparison circuit 6 and the third selection circuit 7 is reduced. The memory 41 is compared and updated. That is, by performing the above-described comparison or update on all the horizontal scanning lines with respect to the captured images at all the projection angles, the highest is achieved through all the captured images captured at the respective projection angles for all the pixels. Only the changed luminance is stored in the luminance memory 41.

Further, since the angle coding memory 42 is provided with the fourth selection circuit 45 connected to the second comparison circuit 6, the same applies to all pixels for each light emission angle. Only the light projection angle when the highest luminance is detected through all the captured images is stored in the angle coding memory 42.

Then, the completed angle encoding memory 42
And the computer 100 measures the three-dimensional shape.

Here, the arithmetic processing method of the spatial code processing means 4 will be described with reference to simple examples shown in FIGS. Here, the number of pixels of the light receiving element 31 of the camera 3 is 3 ×
3 (horizontal direction × vertical direction). Also,
It is assumed that all recording areas of the luminance memory 41 and the angle coding memory 42 have been reset to 0 before the start of measurement.

Since the number of pixels in the horizontal direction is three, the image is taken at the rotation angles θ 0, θ 1, θ 2 of the galvanomirror 23 corresponding to which the slit light R is imaged for each pixel. .

First, the processing when the light projection angle θ = θ0 will be described with reference to FIG. First, an image captured by the light receiving element 31 of the slit light R when the projection angle θ = θ0 is shown in FIG.
It is shown in (A). In the light receiving element 31, the horizontal direction indicates a horizontal address x (numbers assigned to pixels in order from the left in the figure), and the vertical direction indicates a vertical address y (numbers assigned to horizontal scanning lines in order from the top in the figure). I do. Also,
FIG. 13B shows the luminance memory 41 before update recording.

In the output period of the horizontal scanning line of the vertical address y = 1 of the light receiving element 31, the detected luminance of each pixel is sequentially output, and the peak luminance is specified by the peak detecting section 5 as 200 by the end of the output period. At the same time, the horizontal address x is specified as x = 1. Then, when shifting to the flyback period, the specified maximum luminance is compared with the recording luminance of the luminance memory 41, and thereafter, the maximum luminance is updated as the recording luminance (FIG. 13C). Simultaneously with the updating of the luminance memory 41, the contents of the recording area of the horizontal address x = 1 and the vertical address y = 1 in the angle encoding memory 42 are
The projection angle θ0 at that time is updated (FIG. 13
(D)).

The same processing is performed with the vertical addresses y = 2, y =
3 (E) and (F) show the updating of the luminance memory 41 and the angle coding memory 42 when y = 2, and FIGS. 3 (G) and 3 (H) show the case where y = 3. The update of the luminance memory 41 and the angle encoding memory 42 at the time is shown.)

Processing is performed such that the light projection angle θ = θ1 and the light projection angle θ = θ2. Further, the computer (arithmetic unit) 100 extracts an unmeasurable point from the angle code data (spatial coded image) stored in the angle coded memory and further calculates a complement value. After that, the distance in the object coordinate system is calculated from the complemented angle code (space code) and the pixel position stored in the angle coding memory 42.

FIGS. 14 and 15 are flowcharts showing an example of processing up to calculation of an angle code.

First, the camera 3 and the irradiating means 2 are synchronized by the synchronization circuit 43 and the memory address creation circuit 46, and the object S is irradiated with the slit light R and imaged (step S1). With this synchronization, the slit light is imaged on the light receiving element 31 while changing its position for each pixel in the horizontal scanning line direction.

First, according to the captured image at the light projection angle 1, the luminance is output from the horizontal scanning line of the scanning line number 1 in the arrangement order of the pixels on the scanning line. The output period for all the pixels on one horizontal scanning line at this time is the output period for the horizontal scanning line (step S2).

The peak detector 5 based on the captured image
, The maximum luminance is detected for each horizontal scanning line, and at the same time, the horizontal address of the pixel outputting the maximum luminance is detected based on the detection (step S3). The maximum luminance detected at this time is stored in the temporary luminance memory 51, and the horizontal address x is stored in the temporary position memory 81.

The above detections are continuously performed until the output period of one horizontal scanning line ends, and finally, the maximum luminance and the horizontal address are obtained based on the outputs of all the pixels for the horizontal scanning line. And recorded (step S
4).

When the transition from the output period to the flyback period is completed, the gates 91 and 92 of the temporary luminance memory 51 and the temporary position memory 81 are closed (step S5).

When the gate 91 is closed, the maximum luminance in the horizontal scanning line of the scanning line number 1 is output from the temporary luminance memory 51 to the second comparison circuit 6. The second comparison circuit 6 compares the detected maximum luminance with the luminance recorded at the address (x, y) = (x0, 1) in the luminance memory 41 (steps S6 and S7). If the detected maximum luminance is higher, the recording luminance of the address (x0, 1) of the luminance memory 41 is updated by the third selection circuit 7 to the detected maximum luminance value (step S8). .

Note that the luminance memory 41 at this time is initialized in advance before the start of measurement and has a recording luminance of 0. Therefore, if the luminance level of the slit light R is attained, normal updating is performed. Further, when the light projection angle has advanced to 2 or later, the maximum luminance may have already been updated for the same address by the detection based on the captured image up to that point. If the luminance is high, it is updated.

When the brightness memory 41 is updated, the address (x, y) = (x0,
Also in 1), the projection angle 1 at that time is recorded (step S9).

On the other hand, when the detected maximum luminance level is lower, the luminance memory 41 is not updated, and at the same time, the angle coded memory 42 is not recorded (step S10).

Then, for one slit light R, the above steps are repeatedly performed for all the horizontal scanning lines (step S11). Thereby, the position (horizontal address x) of each slit light at the light projection angle 1 in the horizontal scanning line direction is recorded on the angle encoding memory 42.

When the processing is completed for one slit light, an image of the slit light at the next light projection angle is taken, and the above steps are repeated (step S12). Then, when the processing of the slit light at all the projection angles is completed, the information recorded in the angle encoding memory 42 is output to the computer 100 as the measurement data (step S13). The computer 100 performs the complementing process and the three-dimensional shape calculation based on the output from the angle coding memory 42 and displays the result (step S14).

In this embodiment, if the set luminance level of the recording luminance is not high enough to prevent the recording of the detected luminance of the slit light, if there is a portion where the slit light is not irradiated, or if the slit light is generated. It is possible to prevent noise from being selected and taken in when only dark illumination is performed. This is because the noise is considerably lower than the luminance of the slit light, and if the luminance of about half of the slit light is input to the luminance memory 41 in advance as in the above example, the luminance of the noise less than this is lower than the luminance of the slit light. This is because there is no update record.

FIG. 16 shows the spatial code values of a part (6 × 6 area) of the measured spatially coded image. In this example, an unmeasurable point is detected with a code value of 0. In FIG.
Unmeasurable points are indicated by reference numerals 42d and 42e. From the neighboring codes, the pixel denoted by reference numeral 42f is 123, and the reference numeral 42g
The pixel indicated by is estimated to be 122. When this pixel is subjected to a smoothing process using a median value other than 0 of the data in the vicinity of the four surroundings, the result of FIG. 23 is obtained. When comparing FIG. 16 with FIG. 17, the correct measurement data is shown as 42f without being affected.
The pixel indicated by is 123, and the pixel indicated by reference numeral 42g is 122, and smoothing was performed as expected. In this example, A,
The data at point B was complemented using the median value of the code near the four points near the unmeasurable point, but may be eight points instead of four points. Instead of the median value, the average value of the neighboring codes excluding the unmeasurable point may be used.

<Multiple Reflection Noise Removal> FIG. 18 shows an example in which multiple reflection occurs. In the example shown in FIG. 18, the plane of the gear S is imaged from above. The measurement light was emitted from the upper left in the figure. The slit light having a predetermined angle code indicated by the symbol Ra is divided into a normal irradiation Ra and an irradiation R by multiple reflection.
b. When this state is measured by the apparatus shown in FIGS. 10 and 11, a distance image shown in FIG. 19 is obtained.
A blind spot indicated by reference sign S2 occurs in the distance image indicated by reference sign S1. Then, in the front view, noise occurs due to the multiple reflection Rb indicated by the reference numeral S3. As described above, when the shape due to noise overlaps the vicinity of the normal shape, it is difficult to remove not only automatically but also manually.

FIG. 20 shows an example of such a space code at the time of multiple reflection. Pixels for which the space code is 0 are blind spots and, if ignored here, show a monotonically increasing tendency as a whole. However, it is temporarily decreasing around the horizontal pixel coordinates 160 and 205. This part is where the code change due to multiple reflection occurs.

In the example shown in FIG. 20, it is possible to specify a multiple reflection occurrence position by checking the increasing tendency of all the pixels except the pixel of the space code 0. First, from the horizontal pixel coordinates 0 to 255, the increasing tendency is checked, and the pixel (point A) at which the code has started to decrease and the maximum code up to that point are recorded. Next, the pixel position (point B) where the code of the maximum code abnormality at that time is recorded is obtained. This A-
The code between B is a candidate for noise and is referred to herein as an increased code jump section.

Here, there is a portion where the space code at the time of multiple reflection temporarily decreases depending on the shape of the object (around 131 in FIG. 20). At this time, if multiple reflections are removed by searching in one direction, an erroneous result of noise due to multiple reflections occurs between A and B in FIG. Therefore, the decrease tendency is similarly examined from the opposite direction, and the pixel that has turned from the decrease tendency to increase (point C) and the pixel that has returned to decrease again (point D) are determined. Here, the section between CD and D is referred to as a reduced code jump section.

By repeating the above processing, a noise candidate by investigating the increasing tendency and a noise candidate by investigating the decreasing tendency are obtained. Of the noise candidate pixels,
Pixels (between A and C) that are both candidates are pixels having the highest possibility of noise due to multiple reflection.

In correspondence with FIG. 1, in this embodiment, the irradiation step E1 includes an increased space code irradiation step of increasing the space code in the scanning direction of the measurement light and irradiating the space code. Then, the multiple reflection determination step E5 compares the increase / decrease between consecutive pixels of the space code in the scanning direction, and the maximum value of the space code from the start pixel at which the increase tendency is reversed to start decreasing to the time of the transition. Increase code to end pixel beyond
The step of defining an increase code / jump section defining a jump section, and comparing the increase / decrease between consecutive pixels of the space code in the direction opposite to the scanning direction, and starting from the start pixel where the decreasing tendency is reversed to increase. A reduced code / jump section definition step of defining a reduced code / jump section up to an end pixel below the minimum value of the spatial code up to the time of the occurrence. Then, following the decreasing code / jump section defining step, the increasing code / jump section and the decreasing code / jump section
A multiple reflection section determining step of determining a section overlapping with the jump section as a multiple reflection section is provided. This makes it possible to specify a multiple reflection section using a process that can be performed at a relatively high speed.

FIGS. 21 to 23 are flowcharts showing specific processing examples. Here, the number of pixels is 256 × 25
6, the projection angle resolution is 8 bits. 21 to 23
The processing is performed in the order of.

Pixel position: (x, y) Spatial coded image: Code (x, y) Incremental code / jump identification flag: Fmax (x, y)
y) Decrease code / jump identification flag: Fmin (x,
y) Maximum value: Max Minimum value: Min Multiple reflection data identification flag: Err (x, y)

As shown in FIG. 21, first, an increase code jump section is searched for in the increase direction. Initializing the pixel position and the maximum value (step F1),
The value of Code (x, y) of the spatially coded image is the maximum value M
It is determined whether it is larger than ax (step F2).
If the value of the spatially coded image is smaller than the maximum value Max, the increase code / jump identification flag Fmax
(X, y) is set to 1 (step F3). This allows
The coordinates at which the space code has turned to decrease and whether or not the section is a section in which the space code continuously decreases are stored. On the other hand, if the value of the space-coded image is larger than the maximum value, the maximum value is updated with the value of the space code, and the increase code / jump identification flag is set to 0 (step F4). This is repeated in the x direction (horizontal scanning direction) (steps F5 and F6), and further repeated in the vertical scanning direction (steps F7 and F8). At this time, the initial value of x is set to 0, and the value of x is counted up. This allows
We are investigating the increase and decrease of the space code in the horizontal scanning direction. By the processing shown in FIG. 21, in all the spatially coded images,
Fmax (x, y) = 1 in the increased code jump section
Becomes

Subsequently, as shown in FIG. 21, a decrease code jump section is searched for in the decrease direction. In step G1, x = 255 is initialized. Then, it is determined whether the space code is smaller than the minimum value (step G).
2). Usually, since the space code decreases in the reverse direction of the scanning direction, if the space code is not smaller than the minimum value, the reduced code jump identification flag Fmin (x,
y) is set to 1 (step G3). As a result, the coordinates at which the space code has turned to increase and whether or not the section is a section in which the space code continuously increases thereafter are stored. On the other hand, when the value of the space-coded image is smaller than the minimum value, the minimum value is updated, and the value of Fmin (x, y) is set to 0. This is repeated in the x direction (the antiparallel direction of the horizontal scanning direction) (steps G5 and G6), and further repeated in the vertical direction (steps G7 and G8). At this time, the initial value of x is 2
55, and the search in the reverse direction is performed by counting down the value of x. By the processing shown in FIG. 22, Fmin (x, y) = 1 in the reduced code jump section in all the spatially coded images.

Further, as shown in FIG. 23, the values of the initialization x and y are initialized (step H1), the flag of the coordinates is read, and it is confirmed whether both Fmax and Fmin are 1 (step H2). ), Assuming that both sections are overlapping sections, an error is set at the coordinates (step H).
3). On the other hand, when both are 0 or only one is 1, the error flag is set to 0. This is repeated in the horizontal direction (steps H5 and H6) and in the vertical direction (steps H7 and H8). In the example shown in FIG.
In step H4, an identification flag of an incorrect code due to multiple reflection is set. Thereafter, this flag is checked and used for processing such as changing the color at the time of display or not performing the arithmetic processing.

FIG. 24 shows an example in which multiple reflection noise removal according to this embodiment is performed. As described above, according to the present embodiment, multiple reflection can be estimated, and noise can be automatically removed. In addition, an object having a high reflectance such as a metal processing surface can be measured.

Since the present invention is constructed and functions as described above, according to this, in the increase / decrease extraction step, the change of the increase / decrease of the space code in the same direction as the scanning direction of the measurement light in the irradiation step is extracted. Then, when multiple reflection occurs, the traveling direction of the slit light is reversed and travels in the opposite direction to the scanning direction, so that the increasing tendency of the space code is determined to be inverted. Identify the space code in which the increase or decrease of the space code extracted in the process is a decrease or increase which is a change opposite to the predetermined increase or decrease, and the increase or decrease of the space code is reversed. Can be determined as a spatial code due to multiple reflections, whereby even multiple reflections occurring in blind spots can be reliably extracted based on changes in the increase or decrease in spatial codes. , It is possible to provide a good three-dimensional shape measuring method not conventionally being able to perform accurate shape measurement by removing difficult noise removal.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a configuration of a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a relationship between a space code shown in FIG. 1, a position of a light receiving element, and a distance to an object to be measured.

3A and 3B are explanatory diagrams showing a relationship between a measurement light and a space code; FIG. 3A is a diagram showing a relationship between an irradiation angle and an angle code; FIG. 3B corresponds to FIG. 3A; FIG. 3C is a diagram showing a change in the space code, and FIG. 3C is a diagram showing the space code in shades.

FIG. 4 is an explanatory diagram showing the relationship between the measurement light and the space code following FIG. 3, and FIG. 4A is a diagram showing an example in which a small object exists on the camera side of a planar measurement target; , FIG. 4 (B)
4A is a diagram showing a change in a space code corresponding to the slit light shown in FIG. 4A, FIG. 4C is a diagram showing a case where the surface of the measurement object is inclined, and FIG. FIG. 5 is a diagram illustrating an example of a space code corresponding to the slit light illustrated in FIG.

5A and 5B are explanatory diagrams illustrating an example of a measurement target in which multiple reflections have occurred; FIG. 5A is a diagram illustrating an example of a measurement target in which multiple reflections have occurred; FIG. FIG.

FIG. 6 is a block diagram showing a configuration of a three-dimensional shape measuring apparatus according to the present invention.

7 is a perspective view showing an example of a calibration device for calibrating the three-dimensional measurement device shown in FIG.

8 is a diagram showing the calibration two-dimensional gauge disclosed in FIG. 7, wherein FIG. 8 (A) is a front view and FIG. 8 (B) is a side view.

FIG. 9 is a flowchart illustrating an example of a calibration process performed by the device illustrated in FIG. 7;

FIG. 10 is a block diagram showing a configuration of a three-dimensional measuring apparatus using a light section method.

FIG. 11 is a block diagram showing an example of a spatial code processing means shown in FIG.

FIG. 12 (A) is a CCD imaging slit light.
FIG. 12B is an explanatory diagram illustrating an image sensor, and FIG. 12B is an explanatory diagram illustrating outputs of pixels forming a horizontal scanning line of a scanning line number 1 in an arrangement order.

FIG. 13 is an explanatory diagram showing a simplified configuration for explaining the operation of the space code processing means. FIG. 13 (A) shows a CCD image sensor for capturing the first slit light, and FIG.
FIG. 3B shows an initialized luminance memory, and FIG.
FIG. 13C shows a luminance memory in which the luminance of the first scanning line obtained by imaging the slit light in FIG. 13A is recorded, and FIG. 13D is based on the luminance memory in FIG. 4 shows a recorded angle coded memory. FIGS. 13E to 13H show a state in which a luminance memory and an angle coded memory are similarly recorded for each scanning line.

14 is a first part of a flowchart illustrating an example of a space code generation process based on the light section method using the configuration illustrated in FIG. 10;

FIG. 15 is a second half of a flowchart showing an example of processing for generating a space code based on the light section method with the configuration shown in FIG. 10;

FIG. 16 is an explanatory diagram showing an example of a space-coded image having a measurement impossible point.

FIG. 17 is an explanatory diagram showing an example in which the space code image shown in FIG. 22 is complemented.

FIG. 18 is an explanatory diagram illustrating an example of a gear in which multiple reflection has occurred.

FIG. 19 is an explanatory diagram showing a measurement example in the state shown in FIG. 18;

FIG. 20 is a graph illustrating an example of a change in a space code when multiple reflection occurs.

FIG. 21 is a first part of a flowchart illustrating a processing example for specifying a multiple reflection section;

FIG. 22 is a middle part of a flowchart showing a processing example for specifying a multiple reflection section.

FIG. 23 is a second half of a flowchart illustrating a processing example of specifying a multiple reflection section.

FIG. 24 is an explanatory diagram showing an example in which multiple reflection is removed according to the present embodiment.

[Explanation of symbols]

 2 Irradiation mechanism 3 Camera 4 Calculation means 31 Light receiving element 41 Luminance memory 42 Angle coding memory R Slit light S Object to be measured

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Takeshi Nakajima 2-1, Sakuranamiki, Tsuzuki-ku, Yokohama-shi, Kanagawa Prefecture F-term in the Suzuki R & D Center (reference) 2F065 AA04 AA53 DD04 DD12 FF01 FF02 FF09 FF61 GG04 HH05 HH07 HH12 HH14 JJ03 JJ26 LL13 LL62 MM16 QQ24 QQ31 5B057 AA01 BA02 CA13 CB13 CC01 DA20 DB03 DC09 DC30

Claims (6)

[Claims] An irradiation step of irradiating measurement light corresponding to a space code for dividing a space including a measurement object, and forming a predetermined angle with respect to an irradiation angle of the measurement light irradiated in the irradiation step. A light receiving step of receiving the measurement light with each light receiving element two-dimensionally arranged on the light receiving plane, and a space code for each position corresponding to each light receiving element based on the order of the measurement light received in the light receiving step. The space code processing step to be calculated, and the distance from the origin in the coordinate system predetermined on the basis of the space code and the position of the light receiving element calculated in the space code processing step to the surface of the measurement object. A three-dimensional shape measuring method comprising: a distance calculating step of calculating for each light receiving element; wherein the space code processing step includes: changing a change in increase or decrease of a space code in the same direction as a scanning direction of the measurement light in the irradiation step. An increase / decrease extraction step to output, and a space code in which the increase / decrease of the space code extracted in the increase / decrease extraction step is a decrease / increase that is a change opposite to a predetermined increase / decrease, and the space code is specified. A multi-reflection determining step of determining a spatial code in which the increase or decrease of the code is reversed as a spatial code by multiple reflection. 2. The three-dimensional shape measurement according to claim 1, further comprising a deletion step of deleting a space code determined as multiple reflection in the multiple reflection determination step, following the multiple reflection determination step. Method. 3. The method according to claim 1, further comprising an error flag adding step of adding an error flag to the space code determined to be multiple reflection in the multiple reflection determining step, following the multiple reflection determining step. 3D shape measurement method. 4. The method according to claim 1, wherein the irradiating step includes an increasing space code irradiating step of increasing and irradiating the space code with respect to a scanning direction of the measurement light; The increase / decrease of the space code between the start pixel where the increase tendency is reversed and the decrease is reversed and the end pixel exceeding the maximum value of the spatial code from the time of the change is compared.
An increasing code / jump section defining step for defining a jump section, and comparing the increase / decrease between consecutive pixels of the space code in the direction opposite to the scanning direction, and starting from the start pixel whose decreasing tendency is reversed to increase. A reduced code / jump section defining step of defining a reduced code / jump section up to an end pixel below the minimum value of the space code up to the time of the change, and following the reduced code / jump section defining step, 2. The three-dimensional shape measuring method according to claim 1, further comprising a multiple reflection section determination step of determining a section where the increase code jump section overlaps with the decrease code jump section as a multiple reflection section. 5. An irradiating means for irradiating measurement light corresponding to a space code for dividing a space including an object to be measured, and forming a predetermined angle with respect to an irradiation angle of the measuring light radiated by the irradiating means. A light receiving means having light receiving elements arranged two-dimensionally on a light receiving plane, and a space for calculating a space code for each position corresponding to each light receiving element based on the order of measurement light received by each light receiving element of the light receiving means. A space code storage unit for storing a space code calculated by the space code processing unit at a pixel position corresponding to each of the light receiving elements; and a pixel position of the space code storage unit and the corresponding pixel. A distance calculating means for calculating, for each of the light receiving elements, a distance from an origin in a predetermined coordinate system based on a space code stored in the light receiving element. In the three-dimensional shape measuring apparatus comprising: a spatial code processing means, wherein the spatial code image stored in the spatial code storage means changes in increase and decrease of the spatial code in the same direction as the scanning direction of the measurement light by the irradiating means Identify the space code in which the increase or decrease of the space code extracted by the increase / decrease extractor is monotonically decreasing or monotonically increasing in a direction opposite to a predetermined monotonic increase or monotonic decrease. A multi-reflection determining unit for determining a spatial code in which the increase or decrease of the spatial code is reversed as a spatial code by multiple reflection. 6. An irradiation device for irradiating measurement light corresponding to a space code for dividing a space including an object to be measured, and a measurement light irradiated by the irradiation device is determined in advance with respect to an irradiation angle of the measurement light. A light receiving device that receives light at each light receiving element two-dimensionally arranged on a light receiving plane at an angle, and a space code for each position corresponding to each light receiving element based on the order of measurement light received at the light receiving device. A space code processing device to be calculated, and a distance from an origin in a predetermined coordinate system to a surface of the measurement target is calculated for each light receiving element based on a space coded image generated by the space code processing device. A storage medium storing a three-dimensional shape measurement program for measuring the shape of the object to be measured using a three-dimensional shape measurement device having a three-dimensional measurement device. The ram is a command to operate the arithmetic device, an increase / decrease extraction command for extracting a change in increase / decrease of the space code in the same direction as the scanning direction of the measurement light irradiated by the irradiation device, and an extraction in accordance with the increase / decrease extraction command. A space in which the increase / decrease of the space code specified is a monotonically decreasing or monotonically increasing space code which is a change opposite to the predetermined monotonic increase or monotonic decrease, and the space in which the increase / decrease of the space code is reversed. A storage medium storing a program for measuring a three-dimensional shape, comprising a multiple reflection determination command for determining a code as a spatial code by multiple reflection.