TWI832205B - Optical measurement device and measurement method - Google Patents

Abstract

An optical measurement device and measurement method, which mainly uses three laser measuring instruments for laser measurement. First, a sample plate is measured to define the relationship between the laser measuring instruments, and then the plate to be measured is measured, which can achieve convenience The purpose of measuring the board to be tested; in addition, it can also be assisted by image measurement. Image measurement calculates the length of the four sides of the board to be tested by calculating the distance between horizontal and vertical pixels, which can reduce errors.

Description

Optical measurement device and measurement method

The present invention relates to an optical measurement device and a measurement method; in particular, it relates to an optical measurement device and a measurement method that use laser measurement and can be assisted by image measurement.

The floor unit of the raised floor is a rectangular parallelepiped with a square top surface, and its processing accuracy is very high. For example, in some cases, the tolerance range is within plus or minus 0.01mm. However, most of the commonly used measurement methods use manual measurement, which is prone to errors and causes a lot of trouble.

In view of this, the inventor thought hard and actively researched. With many years of experience in related product research, and through continuous testing and improvement, he finally developed the present invention.

The object of the present invention is to provide an optical measuring device that can conveniently measure a board to be tested.

The structure of the present invention to achieve the above object includes: a platform; a first laser measuring instrument installed on one side of the platform; and a second laser measuring instrument installed on the side of the platform relative to the first laser measuring instrument. The other side is aligned horizontally with the first laser measuring instrument and separated by a first separation distance; a third laser measuring instrument is installed on the platform relative to the first laser measuring instrument. The other side of the measuring instrument is separated from the second laser measuring instrument by a second separation distance.

Preferably, a camera is installed above the platform to assist with image measurement.

Preferably, the platform is a height-adjustable structure that can be raised or lowered to facilitate measurement of boards to be tested at different heights.

Another object of the present invention is to provide an optical measurement method that can conveniently measure the board to be tested.

The steps of the present invention to achieve the above object include: S101: Set up a first laser measuring instrument on one side of a platform, and set up a second laser measuring instrument and a third laser measuring instrument on the opposite side of the platform. On the other side of the first laser measuring instrument, the first laser measuring instrument and the second laser measuring instrument are separated by a first separation distance (D1), and the second laser measuring instrument and the third laser measuring instrument are separated by a first separation distance (D1). The radiometric measuring instruments are separated by a predetermined second separation distance (D2); S102: Place a sample plate on the platform; the sample plate is a rectangular parallelepiped, the top surface is square, and has a predetermined left side length of the top surface of the sample plate (L11) , the length of the top surface of the sample plate (L12), the length of the right side of the top surface of the sample plate (L13), and the length of the bottom surface of the top surface of the sample plate (L14); S103: Measure the first, second and third laser measuring instruments respectively. The first laser distance (X1), the second laser distance (X2) and the third laser distance (X3) between the sample plate and the sample plate; S104: Calculate and obtain the value of the first separation distance (D1); S105 : Take the sample board and place a board to be tested on the platform; the board to be tested is a rectangular parallelepiped with a square top surface, with the length of the left side of the top surface of the board to be tested (L15) and the length of the top surface of the board to be tested ( L16), the length of the right side of the top surface of the board to be tested (L17), and the length of the bottom side of the top surface of the board to be tested (L18); S106: respectively 1. The second and third laser measuring instruments measure the fourth laser distance (X4), the fifth laser distance (X5) and the sixth laser distance (X6) between them and the board to be tested; S107: Calculate and obtain the value of the lower side length (L18) of the top surface of the board to be tested.

，可方便確認第一及第二雷射測量儀之間的關係。 Preferably, in step S104, a first formula is used to calculate the value of the first separation distance (D1); the first formula:

, which can easily confirm the relationship between the first and second laser measuring instruments.

，可達到方便測量待測板的目的。 Preferably, in step S107, the second formula is used to calculate the value of the lower side length (L18) of the top surface of the board to be tested; the second formula:

, which can achieve the purpose of conveniently measuring the board to be tested.

Preferably, after step S102, perform steps S201 to S206; S201: Set up a camera above the platform, and use the camera to take pictures to obtain an original image of the sample plate; the camera has a predetermined horizontal resolution and vertical resolution. Resolution; S202: Perform lens fisheye correction on the original image of the sample plate to generate a sample plate correction image; S203: Convert the sample plate correction image into a first grayscale image, and then convert the first grayscale image into a The first contour map; S204: Perform a four-corner point search on the first contour map to obtain a first four-corner point coordinate; the first four-corner point coordinate is the four-corner point coordinate of the sample plate in the sample plate calibration map; S205: Calculation is obtained on the sample board Calibrate the first horizontal pixel range and the first vertical pixel range of the sample board in the calibration chart; S206: Calculate and obtain the first horizontal pixel distance and the first vertical pixel distance in the sample board calibration chart, which can be used to create an image of the test board Measure.

Preferably, after step S105, steps S207~S212 are performed; S207: Use the camera to take pictures to obtain an original image of the board to be tested; S208: Perform lens fisheye correction on the original image of the board to be tested to generate an original image of the board to be tested. Plate correction image; S209: Convert the plate correction image to be tested into a second grayscale image, and then convert the second grayscale image into a second contour image; S210: Perform a four-corner point search on the second contour image to obtain A second four-corner point coordinate; the second four-corner point coordinate is the four-corner point coordinate of the sample plate in the correction chart of the board to be tested; S211: Calculate and obtain the top surface of the board to be tested in the correction chart of the board to be tested The left pixel range, the upper pixel range of the top surface of the board to be tested, the pixel range of the right side of the top surface of the board to be tested, and the pixel range of the lower side of the top surface of the board to be tested; S212: Calculate and obtain the left side of the top surface of the board to be tested in the correction chart of the board to be tested The length, the length of the top side of the board to be tested, the length of the right side of the top surface of the board to be tested, and the length of the bottom side of the top surface of the board to be tested can be used for image measurement of the board to be tested.

Preferably, after step S102, perform steps S301 to S311; S301: Set up a camera above the platform, and use the camera to take pictures to obtain an original image of the sample plate; the camera has a predetermined horizontal resolution and vertical resolution. Resolution; S302: Perform lens fisheye correction on the original image of the sample plate to generate a sample plate correction image; S303: Convert the sample plate correction image into a first grayscale image, and then convert the first grayscale image into a The first contour map; S304: Perform a four-corner point search on the first contour map to obtain a first four-corner point coordinate; the first four-corner point coordinate is corrected on the sample plate The four corner point coordinates of the sample plate in the figure; S305: Set a third four corner point coordinate, and substitute the first four corner point coordinate and the third four corner point coordinate into a first perspective transformation formula to calculate a perspective Transformation matrix; S306: Substitute the perspective transformation matrix into the first perspective transformation formula to generate a second perspective transformation formula; S307: Use the second perspective transformation formula to perform perspective transformation on the sample plate correction image to generate a sample plate Top-down plane image; S308: Convert the top-down plane image of the sample plate into a third grayscale image, and then convert the third grayscale image into a third contour image; S309: Perform four-corner point search on the third contour diagram , obtain a fourth four-corner point coordinate; the fourth four-corner point coordinate is the four corner point coordinates of the sample plate in the top-view plane image of the sample plate; S310; calculate and obtain the sample in the top-view plane image of the sample plate The second horizontal pixel range and the second vertical pixel range of the board; S311: Calculate and obtain the second horizontal distance between pixels and the second distance between vertical pixels in the top-view plane image of the sample board, which can be used for image measurement of the board to be tested.

，在該第一透視變換公式中，xi、yi為該第一四角點座標中的各點的座標，xj、yj為該第三四角點座標中的各點的座標，可方便進行透視變換。 Preferably, the first perspective transformation formula is:

, in the first perspective transformation formula, xi and yi are the coordinates of each point in the first four-corner point coordinates, xj, yj are the coordinates of each point in the third four-corner point coordinates, which can facilitate perspective Transform.

，再將該透視變換矩陣代入該第一透視變換公式中以產生一第二透視變換公式，第二透視變換公式為：

，在該第二透視變換公式中，xk、yk為該樣本板校正圖中的各像素點的座標，算出的xm、ym即為樣本板俯視平面影像圖中的各像素點的座標，可提到測量精度。 Preferably, the perspective transformation matrix can be obtained by bringing the coordinates of each point in the first and third four-corner coordinates into the first perspective transformation formula.

, and then substitute the perspective transformation matrix into the first perspective transformation formula to generate a second perspective transformation formula. The second perspective transformation formula is:

, in the second perspective transformation formula, xk and yk are the coordinates of each pixel point in the sample plate correction map, and the calculated xm and ym are the coordinates of each pixel point in the sample plate top-view plane image map. It can be provided to the measurement accuracy.

Preferably, after step S105, steps S312~S318 are performed first; S312: Use the camera to take pictures to obtain an original image of the board to be tested; S313: Perform lens fisheye correction on the original image of the board to be tested to generate an original image of the board to be tested. Test board correction chart; S314: Use the second perspective transformation formula to perform perspective transformation on the board to be tested correction chart to generate a top-view planar image of the board to be tested; S315: Convert the top-view planar image of the board to be tested into a fourth Grayscale image, and then convert the fourth grayscale image into a fourth contour image; S316: Perform a four-corner point search on the fourth contour image to obtain a fifth four-corner point coordinate; the fifth four-corner point coordinate is in The coordinates of the four corners of the board to be tested in the top-down plane image of the board to be tested; S317: Calculate and obtain the pixel range on the left side of the top surface of the board to be tested and the pixel range on the top surface of the board to be tested in the top-down plane image of the board to be tested , the pixel range on the right side of the top surface of the board to be tested, and the pixel range below the top surface of the board to be tested; S318: Calculate and obtain the length of the left side of the top surface of the board to be tested, the length of the top surface of the board to be tested, and The right side of the top surface of the board to be tested is long, The length of the lower side of the top surface of the board to be tested can be used for image measurement of the board to be tested.

In order to achieve the above and other objects, the technical means, components and effects adopted by the present invention are described below using a preferred embodiment with illustrations.

100: Optical measurement device

1:Platform

11:The first laser measuring instrument

12: Second laser measuring instrument

13: The third laser measuring instrument

21:Camera

3: Bracket

101:Sample plate

102: Board to be tested

D1: first separation distance

D2: The second separation distance

L11: The length of the left side of the top surface of the sample plate

L12: The length of the top surface of the sample plate

L13: The length of the right side of the top surface of the sample plate

L14: The length of the bottom side of the top surface of the sample plate

L15: The length of the left side of the top surface of the board to be tested

L16: The length of the top surface of the board to be tested

L17: The length of the right side of the top surface of the board to be tested

L18: The length of the bottom side of the top surface of the board to be tested

PA1: Original image of sample board

PA2: Original image of the board to be tested

PB1: Sample plate calibration chart

PB2: Calibration chart of the board to be tested

PC1: first grayscale image

PD1: First contour map

PE1: Sample plate top view plan image

PE2: Planar image of the board to be tested from above

PF1: The third grayscale image

PF2: The fourth grayscale image

PG1: Third contour map

PG2: Fourth contour map

S101~S107, S201~S212, S301~S318: steps

X1: first laser distance

X2: The second laser distance

X3: The third laser distance

X4: The fourth laser distance

X5: The fifth laser distance

X6: The sixth laser distance

[Fig. 1] is a flow chart of the first embodiment of the present invention.

[Fig. 2] is a schematic diagram of the optical measurement device of the present invention.

[Fig. 3] is a schematic diagram of the relationship between the first, second and third laser measuring instruments of the present invention and the sample plate.

[Fig. 4] is a schematic diagram of the relationship between the first, second and third laser measuring instruments of the present invention and the board to be tested.

[Fig. 5] is a flow chart of the second embodiment of the present invention.

[Fig. 6] is a flow chart of the third embodiment of the present invention.

[Fig. 7] is a schematic diagram of the original drawing of the sample plate of the present invention.

[Fig. 8] is a schematic diagram of a sample plate calibration diagram of the present invention.

[Fig. 9] is a schematic diagram of the first grayscale image and the first contour image of the present invention.

[Fig. 10] is a schematic diagram of a top plan view of the sample plate of the present invention.

[Fig. 11] is a schematic diagram of the third grayscale image and the third contour image of the present invention.

[Fig. 12] is a schematic diagram of the original drawing of the board to be tested according to the present invention.

[Fig. 13] is a schematic diagram of the calibration diagram of the board to be tested according to the present invention.

[Fig. 14] is a schematic diagram of a top plan view of the board to be tested according to the present invention.

[Fig. 15] is a schematic diagram of the fourth grayscale image and the fourth contour image of the present invention.

Figures 1 to 4 show the first embodiment of the present invention. As shown in Figures 1 to 4, the optical measurement device and measurement method of the present invention include the following steps: S101: Set up a first laser measuring instrument 11 on one side of a platform 1, and use a second laser measuring instrument 11 to The instrument 12 and a third laser measuring instrument 13 are set up on the other side of the platform 1 relative to the first laser measuring instrument 11. The first laser measuring instrument 11 and the second laser measuring instrument 12 are separated by a first interval. The distance D1, the second laser measuring instrument 12 and the third laser measuring instrument 13 are separated by a second separation distance D2; S102: Place a sample plate 101 on the platform 1; the sample plate 101 is a rectangular parallelepiped and the top surface is square. It has a predetermined length L11 on the left side of the top surface of the sample plate, L12 on the top side of the sample plate, L13 on the right side of the top surface of the sample plate, and L14 on the bottom side of the top surface of the sample plate; S103: Measure with the first, second and third lasers respectively. The instrument measures the first laser distance X1, the second laser distance X2 and the third laser distance X3 between it and the sample plate; S104: Calculate and obtain the value of the first separation distance D1; S105: Take away the sample plate 101, Place a board 102 to be tested on the platform 1; the board 102 to be tested is a rectangular parallelepiped with a square top surface, with a length of L15 on the left side of the top surface of the board to be tested, a length of L16 on the top side of the top surface of the board to be tested, and a length on the right side of the top surface of the board to be tested. L17, the length of the lower side of the top surface of the board to be tested is L18; S106: Use the first, second and third laser measuring instruments 11, 12 and 13 to measure the fourth laser distance X4 between it and the board to be tested 102. The fifth laser spacing is X5 and the sixth laser spacing is This will be explained in detail below.

The platform that cooperates with the above-mentioned optical measurement device and measurement method can be a conveyor belt (not shown in the figure) that transports the board to be tested. Of course, it can also be built separately. An optical measurement device 100 is constructed to perform measurement. The optical measurement device 100 includes: a platform 1, which can carry a sample plate or a plate to be tested. The platform has a first side, a second side, a third side and a fourth side, wherein the first side and the third side is the opposite side, and is connected to the second side and the fourth side respectively; a first laser measuring instrument 11 is erected on one side of the platform 1 (i.e., the first side of the platform); a second laser measuring instrument 12 is erected On the other side of the platform 1 relative to the first laser measuring instrument 11 (that is, the third side of the platform), it is horizontally aligned with the first laser measuring instrument 11 and separated by a first separation distance D1; The three laser measuring instruments 13 are installed on the other side of the platform 1 relative to the first laser measuring instrument 11 (that is, the third side of the platform), and are separated from the second laser measuring instrument 12 by a second separation distance D2. ; This structure can facilitate the use of optical measurement devices and measurement methods to measure the side length of the board to be measured. In addition, in order to facilitate image measurement, a camera 21 can also be installed above the platform. The bracket 3 for erecting the first, second and third laser measuring instruments 11, 12, 13 and erecting the camera 21 is a common bracket structure and will not be described again.

Step S101 is to set up a first laser measuring instrument 11 on one side of a platform 1, and to set up a second laser measuring instrument 12 and a third laser measuring instrument 13 on the side of the platform 1 relative to the first laser measuring instrument. On the other side of the laser measuring instrument 11, the first laser measuring instrument 11 and the second laser measuring instrument 12 are separated by a first separation distance D1, and the second laser measuring instrument 12 and the third laser measuring instrument 13 are separated by a first separation distance D1. The two separation distances are D2.

The first laser measuring instrument 11 and the second laser measuring instrument 12 should be aligned horizontally, for example, so that the laser light of the first laser measuring instrument 11 overlaps with the laser light of the second laser measuring instrument 12, or so that the second laser measuring instrument 12 overlaps. The laser lights of the first laser measuring instrument 11 and the second laser measuring instrument 12 hit each other's mirror surfaces. The laser lights of the second laser measuring instrument 12 and the third laser measuring instrument 13 are parallel to each other.

Step S102 is to place a sample plate 101 on the platform 1; the sample plate 101 is a rectangular parallelepiped with a square top surface and a predetermined sample plate top surface. The length of the left side is L11, the length of the top side of the sample plate is L12, the length of the right side of the top side of the sample plate is L13, and the length of the bottom side of the top side of the sample plate is L14.

Generally speaking, the sample plate 101 is specially customized, so the sample plate 101 has four side lengths L11 to L14 with predetermined and known values, which can be used as a basis for measurement. In addition, the top surface of the sample plate 101 can be square, with the lengths L11 to L14 of its four sides being equal, so as to facilitate operation.

Step S103 is to measure the first laser distance X1, the second laser distance X2 and the third laser distance between the sample plate 101 and the first, second and third laser measuring instruments 11, 12 and 13 respectively. X3.

Step S104 is to calculate and obtain the value of the first separation distance D1.

There is more than one way to calculate the first separation distance D1. For example, the value of the first separation distance D1 can be calculated using the following first formula. The first formula is:

Calculating the first separation distance D1 by using the first, second and third laser measuring instruments 11, 12 and 13 in conjunction with the first formula can easily confirm the relationship between the first and second laser measuring instruments and ensure Even if the sample plate or the plate to be tested is slightly tilted, it can still be measured correctly. In addition, when the laser measuring instrument is replaced, moved, or reset, the value of the first separation distance D1 may be affected. In this case, you only need to re-insert the sample plate and perform steps S101 to S104 to obtain a new first separation distance D1. The separation distance is D1. Furthermore, the distance between the mirror of different laser measuring instruments and the sensing object (for example For example, the first laser distance X1) is difficult to measure when installing the laser measuring instrument. Therefore, by measuring the sample plate 101 to calculate the first distance D1, the error can be reduced.

Step S105 is to remove the sample plate 101 and place a plate 102 to be tested on the platform 1; the plate 102 to be tested can be a floor unit of a raised floor, which is a rectangular parallelepiped with a square top surface and a length of L15, the length of the top side of the board to be tested is L16, the length of the right side of the top surface of the board to be tested is L17, and the length of the bottom side of the top surface of the board to be tested is L18.

The values of the lengths L15 ~ L18 of the four sides of the board to be tested 102 are unknown. The purpose of this method is to conveniently measure the values of the lengths L15 ~ L18 of the four sides of the board to be tested 102 so as to facilitate the user to evaluate the processing condition of the board to be tested.

Step S106 is to measure the fourth laser distance X4, the fifth laser distance X5 and the sixth laser distance between the first, second and third laser measuring instruments 11, 12 and 13 and the board to be tested 102 respectively. Spacing X6.

Step S107 is to calculate and obtain the value of the lower side length L18 of the top surface of the board to be tested.

There is more than one way to calculate the bottom side length L18 of the top surface of the board to be tested. For example, the value of the bottom side length L18 of the top surface of the board to be tested can be calculated using the second formula below. The second formula is:

Generally speaking, this method can be used to measure the board to be tested after milling, so as to measure whether the four side lengths of the board to be tested after milling are within 1 cm. within the difference range. Of course, in order to further ensure the measurement accuracy, you can use other formulas to calculate the three side lengths L15~17 other than the bottom side length L18 of the top surface of the board to be tested, or rotate the board to be tested about 90 degrees and then measure the length of one side, and proceed together. After one to three times, the values of L15~L18 of the four sides of the board to be tested can be obtained.

Through the laser measurement in steps S101 to S107, the side length value of the board to be tested can be conveniently measured. In addition, because only three laser measuring instruments are used, the structure is simple, so it can be set up to match the processing flow of the board to be tested. For example, using the conveyor belt that transports the board to be tested as a platform, a group of more than three laser measuring instruments can be set up. On the front side and/or the rear side of the processing equipment for the board to be tested, the board to be tested can be measured together with the board to be tested (not shown in the figure).

Figure 5 is a second embodiment of the present invention. As shown in Figure 5, the aforementioned steps S101~S107 can already measure the values of the four side lengths L15~L18 of the board to be tested. However, in order to reduce errors, when performing steps S101 to S107, the image measurement of steps S201 to S212 can be interspersed for assistance.

Step S201 is to set up a camera above the platform and use the camera to take pictures to obtain a sample plate original image PA1; the camera has predetermined horizontal resolution and vertical resolution.

Step S202 is to perform lens fisheye correction on the original sample plate image PA1 to generate a sample plate correction image PB1.

Fisheye correction through the lens can reduce the distortion caused by the fisheye lens.

Step S203 is to convert the sample plate correction chart PB1 into a first Grayscale image PC1, and then convert the first grayscale image PC1 into a first contour image PD1.

Converting the sample plate correction chart PB1 into the first grayscale image PC1 and then into a first profile image PD1 can reduce the impact of problems such as reflection and color difference, and facilitate the search for the sample plate in the sample plate correction chart PB1. Four corner point coordinates.

Step S204 is to perform a four-corner point search on the first contour map PD1 to obtain a first four-corner point coordinate; the first four-corner point coordinate is the four-corner point coordinate of the sample plate in the sample plate correction map PB1, which is also in the first grayscale. The coordinates of the four corner points of the sample plate in the degree diagram PC1 and the first contour diagram PD1.

Step S205 is to calculate and obtain the first horizontal pixel range R21 and the first vertical pixel range R22 of the sample plate in the sample plate correction map PB1.

Step S206 is to calculate and obtain the first horizontal inter-pixel distance PP21 and the first vertical inter-pixel distance PP22 in the sample plate correction map PB1.

By using the inter-pixel distances PP21 and PP22 of the sample plate correction chart PB1 as a benchmark for measuring the plate to be tested, the measurement accuracy can be improved and errors caused by positional deviation or rotation caused by replacing the plate to be tested can be reduced.

Step S207 is to use a camera to take pictures to obtain an original image PA2 of the board to be tested.

Step S208 is to perform lens fisheye correction on the original image PA2 of the board to be tested, and generate a correction image PB2 of the board to be tested.

Step S209 is to convert the correction image PB2 of the board to be tested into a second grayscale image PC2, and then convert the second grayscale image PC2 into a second contour image PD2.

Step S210 is to perform a four-corner point search on the second contour image PD2 to obtain a second four-corner point coordinate; the second four-corner point coordinate is on the board to be tested. Calibrate the coordinates of the four corner points of the sample plate in Figure PB2.

Step S211 is to calculate and obtain the pixel range R23 on the left side of the top surface of the board to be tested, the pixel range R24 on the upper side of the top surface of the board to be tested, the pixel range R25 on the right side of the top surface of the board to be tested, and the bottom side of the top surface of the board to be tested in the correction chart PB2 of the board to be tested. Pixel range R26.

Step S212 is to calculate and obtain the left length L21 of the top surface of the board to be tested, the length L22 of the top surface of the board to be tested, the right length L23 of the top surface of the board to be tested, and the length L24 of the bottom surface of the top surface of the board to be tested in the correction chart PB2 of the board to be tested.

Through the image measurement in steps S201 to S212, the values of the four side lengths L21 to L24 of the board to be tested can be easily obtained. In addition, it can also be analyzed together with laser measurement. For example, in situations with high accuracy requirements, the values of the four-side length L15~L18 of the board to be tested obtained by laser measurement and the four-side length of the board to be tested obtained by image measurement can be required. Only when the values of L21~L24 meet the predetermined tolerance range can it be considered a qualified board to be tested.

Figure 6 is a third embodiment of the present invention. As shown in FIG. 6 , when performing steps S101 to S107, the image measurement of steps S301 to S318 may also be interspersed for assistance. The third embodiment roughly adds perspective transformation on the basis of the second embodiment, thereby reducing possible errors caused by the tilt of the top surface of the board to be measured, thereby improving measurement accuracy. The image measurement assistance in steps S201 to S212 and S301 to S318 mainly uses a camera to obtain images for measurement, and can be performed together with steps S101 to S107. For example, steps S201 to S206 and S301 to S311 are performed after step S102, and steps S207 to S212 and S312 to S318 are performed after step S105.

Steps S301 to S304 are the same as steps S201 to S204. in, The purpose of finding the coordinates of the first four corner points in steps S201 to S204 is to calculate and obtain the inter-pixel distances PP21 to PP22 in the sample plate correction map PB1, while the purpose of finding the coordinates of the first four corner points in steps S301 to S304 is to perform subsequent perspective transformation.

Step S305 is to set a third four-corner point coordinate, and substitute the first four-corner point coordinate and the third four-corner point coordinate into a first perspective transformation formula to calculate a perspective transformation matrix.

The setting value of the coordinates of the third and fourth corner points can be based on the coordinates of the first four corner points, and a range is set to a value smaller than the coordinates of the first four corner points, thereby improving accuracy. The perspective transformation formula is a general formula. In the third embodiment, the first perspective transformation formula is:

In the first perspective transformation formula, xi and yi are the coordinates of each point in the first four-corner coordinates, and xj and yj are the coordinates of each point in the third four-corner coordinates. By bringing the coordinates of each point in the first and third four-corner coordinates into the first perspective transformation formula, the perspective transformation matrix can be obtained. The perspective transformation matrix is:

Step S306 is to substitute the perspective transformation matrix into the first perspective transformation formula to generate a second perspective transformation formula.

Substituting the perspective transformation matrix into the first perspective transformation formula to generate a second perspective transformation formula, the second perspective transformation formula is:

In the second perspective transformation formula, xk and yk are the coordinates of each pixel in the sample plate correction map PB1, and the calculated xm and ym are the coordinates of each pixel in the sample plate top-view plane image PE1.

Step S307: Use the second perspective transformation formula to perform perspective transformation on the sample plate correction image PB1 to generate a sample plate top plan image PE1.

Step S308 is to convert the sample plate top plan image PE1 into a third grayscale image PF1, and then convert the third grayscale image PF1 into a third contour image PG1.

Step S309 is to perform a four-corner point search on the third contour image PG1 to obtain a fourth four-corner point coordinate; the fourth four-corner point coordinate is the four corner point coordinates of the sample plate in the sample plate top-view plane image PE1.

Step S310 is to calculate and obtain the second horizontal pixel range R31 and the second vertical pixel range R32 of the sample plate in the sample plate top plan image PE1.

Step S311 is to calculate and obtain the second horizontal inter-pixel distance PP31 and the second vertical inter-pixel distance PP32 in the top plan image PE1 of the sample plate.

The general principles of steps S308 to S311 are the same as those of steps S203 to S206, but the targets are different. Steps S203~S206 act on the passing mirror Sample plate correction chart PB1 for fish eye correction. Steps S308 to S311 act on the top-view planar image PE1 of the sample plate that has undergone lens fisheye correction and perspective transformation, which can further improve the measurement accuracy.

Step S312 is to use a camera to take pictures to obtain an original image PA2 of the board to be tested.

Step S313 is to perform lens fisheye correction on the original image PA2 of the board to be tested, and generate a correction image PB2 of the board to be tested.

Step S314 is to perform perspective transformation on the correction image PB2 of the board to be tested using the second perspective transformation formula to generate a top-view planar image PE2 of the board to be tested.

When step S314 is performed, xk and yk of the second perspective transformation formula are the coordinates of each pixel in the correction image PB2 of the plate to be tested, and the calculated xm and ym are the coordinates of each pixel in the top-view plane image PE2 of the plate to be tested. coordinates. The perspective transformation performed in steps S307 and S314 can convert possibly tilted sample plates and plates to be tested into flat images, thereby reducing errors.

Step S315 is to convert the top planar image PE2 of the board to be tested into a fourth grayscale image PF2, and then convert the fourth grayscale image PF2 into a fourth contour image PG2.

Step S316 is to perform a four-corner point search on the fourth contour image PG2 to obtain a fifth four-corner point coordinates; the fifth four-corner point coordinates are the four-corner point coordinates of the board to be tested in the top-down plane image of the board to be tested PE2.

Step S317: Calculate and obtain the pixel range R33 on the left side of the top surface of the board to be tested, the pixel range R34 on the upper side of the top surface of the board to be tested, the pixel range R35 on the right side of the top surface of the board to be tested, and the pixel range R35 on the top side of the board to be tested in the top-view plane image PE2 of the board to be tested. Under the surface Edge pixel range R36.

Step S318: Calculate and obtain the length of the left side of the top surface of the board to be tested L31, the length of the top surface of the board to be tested L32, the length of the right side of the top surface of the board to be tested L33, and the length of the bottom side of the top surface of the board to be tested in the top plane image PE2 of the board to be tested. L34.

In the above-mentioned embodiments, for example, the first to sixth laser spacings X1 to X6 are measured values, and the average value can be taken as the final value after multiple measurements (for example, 60 times) to reduce errors.

The first separation distance D1 can be easily calculated through the optical measurement device and measurement method, so it can be used to measure boards of different sizes. In addition, the platform 1 can be a height-adjustable structure to control the rise or fall of the board to be tested, so that boards to be tested at different heights can be measured without adjusting the first, second and third laser measuring instruments.

In order to facilitate understanding of the spirit of the present invention, the following examples are provided.

Example 1 uses steps S101 to S107 to measure the lengths L15 to L18 of the four sides of the board to be tested.

Proceed to step S101. At this time, the first separation distance D1 is unknown, and the second separation distance D2 is 240 mm.

Proceed to step S102. The predetermined left length L11 of the top surface of the sample plate, the length L12 of the top surface of the sample plate, the length L13 of the right side of the top surface of the sample plate, and the length L14 of the bottom side of the top surface of the sample plate are all 600.017 mm.

Proceed to step S103 and measure the first laser distance X1 to be 153.623mm, the second laser distance X2 to be 216.377mm, and the third laser distance X3 to be 214.311mm.

Proceed to step S104 and calculate the first separation distance D1 to be 970.039 mm.

Proceed to step S105. At this time, the length of the left side of the top surface of the board to be tested is L15, the length of the top side of the board to be tested is L16, the length of the right side of the top surface of the board to be tested is L17, and the length of the bottom side of the top surface of the board to be tested is L18.

Step S106 is performed, and the fourth laser distance X4 is measured to be 154.589mm, the fifth laser distance X5 is 215.636mm, and the sixth laser distance X6 is 214.641mm.

Proceed to step S107. The length L18 of the lower side of the top surface of the board to be tested is 599.809mm. Rotate the board to be tested about 90 degrees and then perform S101~S107 three times in total. The length of the left side of the top surface of the board to be tested is L15, the length of the top side of the board to be tested is L16, and the length of the right side of the top surface of the board to be tested is L17, all of which are 599.809mm.

Example 2 intersperses steps S101 to S107 with steps S301 to S318 to measure the four-side lengths L15 to L18 and L31 to L34 of two sets of boards to be tested. The two sets of values can be compared and analyzed with each other. In Example 2, steps S101 to S107 are not repeated.

As shown in Figure 7, step S301 is performed to obtain a sample plate original image PA1. In Example 2, the camera has a horizontal resolution of 3200pixels and a vertical resolution of 1800pixels, such as Logitech 4k Brio.

As shown in Figure 8, step S302 is performed to generate a sample plate correction chart PB1.

As shown in Figure 9, step S303 is performed to generate the first grayscale image PC1 and the first contour image PD1.

Proceed to step S304. The coordinates of the first four corner points are: upper left xi1: 92, yi1: 609, lower left xi2: 107, yi2: 2147, upper right xi3: 1623, yi3: 596, lower right xi4: 1648, yi4: 2124.

Proceed to step S305. The coordinates of the third and fourth corner points are: upper left xj1:107, yj1:609, lower left xj2:107, yj2:2147, upper right xj3:1623, yj3:609, lower right xj4:1623, yj4:2124. By bringing the coordinates of each point in the first and third four-corner coordinates into the first perspective transformation formula, the perspective transformation matrix can be obtained. The perspective transformation matrix is:

Proceed to step S306, the second perspective transformation formula is:

As shown in Figure 10, step S307 is performed to generate a top plan image PE1 of the sample plate.

As shown in Figure 11, step S308 is performed to generate a third grayscale image PF1 and a third contour image PG1.

Proceed to step S309. The coordinates of the fourth four corner points are: upper left xm1:108, ym1:610, lower left xm2:108, ym2:2125, upper right xm3:1623, ym3:610, lower right xm4:1623, ym4:2125.

Proceed to step S310, the second horizontal pixel range R31 is |xm3-xm1|=1515mm/pixel, and the second vertical pixel range R32 is |ym2-ym1|=1515mm/pixel.

Proceed to step S311, the second horizontal inter-pixel distance PP31 is L14/R31=0.396051, and the second vertical inter-pixel distance PP32 is L13/R32=0.396051.

As shown in Figure 12, step S312 is performed to obtain an original image PA2 of the board to be tested.

As shown in Figure 13, step S313 is performed to generate a correction chart PB2 of the plate to be tested.

As shown in Figure 14, step S314 is performed to generate a top plan image PE2 of the board to be tested.

As shown in Figure 15, step S315 is performed to generate a fourth grayscale image PF2 and a fourth contour image PG2.

Proceed to step S316. The coordinates of the fifth four-corner point are: upper left xn1:109, yn1:617, lower left xn2:109, yn2:2130, upper right xn3:1622, yn3:617, lower right xn4:1622, yn4:2130.

Proceed to step S317, the pixel range R33 on the left side of the top surface of the board to be tested is |yn2-yn1|=1513mm/pixel, the pixel range R34 on the top surface of the board to be tested is |xn3-xn1|=1513mm/pixel, and the right side of the top surface of the board to be tested is The pixel range R35 is |yn4-yn3|=1513mm/pixel, and the pixel range R36 under the top surface of the board to be tested is |xn4-xn2|=1513mm/pixel.

Proceed to step S318. The length L31 of the left side of the top surface of the board to be tested is PP31*R33=599.225mm. The length L32 of the top side of the board to be tested is PP32*R34=599.225mm. The length L33 of the right side of the top surface of the board to be tested is PP31*R35=599.225. mm, the length L34 of the lower side of the top surface of the board to be tested is PP32*R36=599.225mm.

The first, second and third laser measuring instruments 11, 12, 13 and the camera 21 can all be connected to a computer (not shown in the figure) in a wired or wireless manner, and the calculations and image conversions in the above steps are It can be processed by the computer, thereby saving costs.

The above-mentioned embodiments of the present invention are only for convenience of explanation. They should not be used to limit the significance of the present invention. That is, all various transformation designs based on the listed patent scope should be included in the patent scope of the present invention. middle.

1:Platform

11:The first laser measuring instrument

12: Second laser measuring instrument

13: The third laser measuring instrument

101:Sample plate

D1: first separation distance

D2: The second separation distance

L11: The length of the left side of the top surface of the sample plate

L12: The length of the top surface of the sample plate

L13: The length of the right side of the top surface of the sample plate

L14: The length of the bottom side of the top surface of the sample plate

X1: first laser distance

X2: The second laser distance

X3: The third laser distance

Claims (12)

An optical measurement device, which includes: a platform carrying a board to be measured, the platform having a first side, a second side, a third side and a fourth side, wherein the first side and the third side are opposite sides, and are respectively connected to the second side and the fourth side; a first laser measuring instrument is installed on the first side of the platform; a second laser measuring instrument is installed on the platform relative to the first laser measuring instrument The third side is horizontally aligned with the first laser measuring instrument and is separated by a first separation distance; a third laser measuring instrument is installed on the platform relative to the first laser measuring instrument. The third side is separated from the second laser measuring instrument by a second separation distance; the laser light of the first laser measuring instrument overlaps with the laser light of the second laser measuring instrument. The optical measurement device of claim 1, wherein a camera is installed above the platform. Such as the optical measurement device of claim 1, wherein the platform is a height-adjustable structure that can be raised or lowered. An optical measurement method, which includes the following steps: S101: Set up a first laser measuring instrument on one side of a platform, and set up a second laser measuring instrument and a third laser measuring instrument on the platform Relative to the other side of the first laser measuring instrument, the first laser measuring instrument is separated from the second laser measuring instrument by a first separation distance (D1), and the second laser measuring instrument is separated from the third laser measuring instrument. Three laser measuring instruments Spacing a predetermined second spacing distance (D2); S102: Place a sample plate on the platform; the sample plate is a rectangular parallelepiped, the top surface is square, and has a predetermined left side length (L11) of the top surface of the sample plate. The length of the top side (L12), the length of the right side of the top side of the sample plate (L13), and the length of the bottom side of the top side of the sample plate (L14); S103: Use the first, second and third laser measuring instruments to measure them and the sample respectively. The first laser spacing (X1), the second laser spacing (X2) and the third laser spacing (X3) between the boards; S104: Calculate and obtain the value of the first spacing distance (D1); S105: Take away For this sample board, place a board to be tested on the platform; the board to be tested is a rectangular parallelepiped with a square top surface, with the length of the left side of the top surface of the board to be tested (L15), the length of the top side of the board to be tested (L16), The length of the right side of the top surface of the board to be tested (L17), and the length of the bottom side of the top surface of the board to be tested (L18); S106: Use the first, second and third laser measuring instruments to measure the third distance between it and the board to be tested. The fourth laser distance (X4), the fifth laser distance (X5) and the sixth laser distance (X6); S107: Calculate and obtain the value of the lower side length (L18) of the top surface of the board to be tested. The optical measurement method of claim 4, wherein in step S104, the value of the first separation distance (D1) is calculated using a first formula; the first formula:

For example, the optical measurement method of claim 4, wherein in step S107, the value of the lower side length (L18) of the top surface of the board to be measured is calculated using a second formula; the second formula:

For example, the optical measurement method of claim 4, wherein after step S102, steps S201 to S206 are performed; S201: Set up a camera above the platform, and use the camera to take pictures to obtain an original image of the sample plate; the camera has Predetermined horizontal resolution and vertical resolution; S202: Perform lens fisheye correction on the original sample plate image to generate a sample plate correction image; S203: Convert the sample plate correction image into a first grayscale image, and then convert the sample plate correction image into a first grayscale image. The first grayscale image is converted into a first contour image; S204: Perform a four-corner point search on the first contour image to obtain a first four-corner point coordinate; the first four-corner point coordinate is in the sample plate correction image The coordinates of the four corner points of the sample plate; S205: Calculate and obtain the first horizontal pixel range and the first vertical pixel range of the sample plate in the sample plate correction map; S206: Calculate and obtain the first horizontal pixel range in the sample plate correction map distance and the distance between the first vertical pixels. For example, the optical measurement method of claim 7, wherein after step S105, steps S207~S212 are performed; S207: use the camera to take pictures to obtain an original image of the board to be tested; S208: Perform lens fisheye correction on the original image of the board to be tested to generate a correction image of the board to be tested; S209: Convert the correction image of the board to be tested into a second grayscale image, and then convert the second grayscale image into a Second contour map; S210: Perform a four-corner point search on the second contour map to obtain a second four-corner point coordinate; the first four-corner point coordinate is the four-corner point coordinate of the sample plate in the calibration chart of the plate to be tested ; S211: Calculate and obtain the pixel range on the left side of the top surface of the board to be tested, the pixel range on the upper side of the top surface of the board to be tested, the pixel range on the right side of the top surface of the board to be tested, and the pixel range on the bottom side of the top surface of the board to be tested in the correction chart of the board to be tested; S212: Calculate and obtain the length of the left side of the top surface of the board to be tested, the length of the top surface of the board to be tested, the length of the right side of the top surface of the board to be tested, and the length of the bottom side of the top surface of the board to be tested in the correction chart of the board to be tested. For example, the optical measurement method of claim 4, wherein after step S102, steps S301 to S311 are performed; S301: Set up a camera above the platform, and use the camera to take pictures to obtain an original image of the sample plate; the camera has Predetermined horizontal resolution and vertical resolution; S302: Perform lens fisheye correction on the original sample plate image to generate a sample plate correction image; S303: Convert the sample plate correction image into a first grayscale image, and then convert the sample plate correction image into a first grayscale image. The first grayscale image is converted into a first contour image; S304: Perform a four-corner point search on the first contour image to obtain a first four-corner point coordinate; the first four-corner point coordinate is in the sample plate correction image The four corner point coordinates of the sample plate in; S305: Set a third four corner point coordinate, and substitute the first four corner point coordinate and the third four corner point coordinate into a first perspective transformation formula to calculate a perspective transformation matrix; S306: Substitute the perspective transformation matrix into the first perspective transformation formula to generate a second perspective transformation formula; S307: Use the second perspective transformation formula to perform perspective transformation on the sample plate correction image to generate a sample plate top view Plane image; S308: Convert the top-view planar image of the sample plate into a third grayscale image, and then convert the third grayscale image into a third contour map; S309: Perform a four-corner point search on the third contour map, Obtain a fourth four-corner point coordinate; the fourth four-corner point coordinate is the four corner point coordinates of the sample plate in the top-view planar image of the sample plate; S310: Calculate and obtain the sample plate in the top-view planar image of the sample plate The second horizontal pixel range and the second vertical pixel range; S311: Calculate and obtain the second horizontal inter-pixel distance and the second vertical inter-pixel distance in the top-view plane image of the sample plate. For example, the optical measurement method of claim 9, wherein the first perspective transformation formula is:

, in the first perspective transformation formula, xi and yi are the coordinates of each point in the first four-corner point coordinates, and xj and yj are the coordinates of each point in the third four-corner point coordinates. The optical measurement method of claim 10, wherein the perspective transformation matrix can be obtained by bringing the coordinates of each point in the first and third four-corner point coordinates into the first perspective transformation formula.

, and then substitute the perspective transformation matrix into the first perspective transformation formula to generate a second perspective transformation formula. The second perspective transformation formula is:

, in the second perspective transformation formula, xk and yk are the coordinates of each pixel point in the sample plate correction map, and the calculated xm and ym are the coordinates of each pixel point in the sample plate top-view plane image. For example, the optical measurement method of claim 11, wherein after step S105, steps S312 to S318 are first performed; S312: use the camera to take pictures to obtain an original image of the board to be tested; S313: take a lens of the original image of the board to be tested. Fisheye correction generates a correction image of the board to be tested; S314: Use the second perspective transformation formula to perform perspective transformation on the correction chart of the board to be tested to generate a planar image of the board to be tested; S315: View the board to be tested from a top view The plane image image is converted into a fourth grayscale image, and then the fourth grayscale image is converted into a fourth contour image; S316: Perform a four-corner point search on the fourth contour image to obtain a fifth and fourth contour image. Corner point coordinates; the fifth four corner point coordinates are the four corner point coordinates of the board to be tested in the top-down plane image of the board to be tested; S317: Calculate and obtain the top of the board to be tested in the top-down plane image of the board to be tested The pixel range on the left side of the surface, the upper pixel range on the top surface of the board to be tested, the pixel range on the right side of the top surface of the board to be tested, and the pixel range on the lower side of the top surface of the board to be tested; S318: Calculate and obtain the board to be tested in the top-view plane image of the board to be tested The length of the left side of the top surface, the length of the top side of the board to be tested, the length of the right side of the top surface of the board to be tested, and the length of the bottom side of the top surface of the board to be tested.

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