JP2712642B2 - Component tilt detection method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a component inclination detecting method for obtaining a mounting correction angle of an electronic component in an electronic component mounting machine.

2. Description of the Related Art In an electronic component mounting machine that mounts electronic components on a substrate, the electronic components to be mounted were previously positioned by a setting mechanism, but recently, the position and inclination of the components are detected using a visual recognition device. Then, after the position and the inclination are corrected, they are mounted.

In order to detect the inclination of an electronic component to which visual recognition is applied, there is a conventional method of obtaining a tilt by obtaining a synergistic moment of inertia and a second moment of inertia around the center of gravity of the component.

In this method, a part is approximated by an ellipse, and its major axis is used as the inclination of the part.

However, in this method, when the shape of the component is close to a square, the main axis is not determined and the inclination is not obtained, and when the nozzle sucking the component protrudes from the contour of the component, the main shaft is There is a problem that a difference is generated between the inclination obtained by being drawn by the nozzle and the original inclination of the component.

Therefore, the present invention, even when the shape of the part is nearly square,
Even if some nozzles protrude from the part, the inclination of the part can be accurately obtained.

Means for Solving the Problems In order to solve the above problems, the present invention provides a first method for detecting an angle indicating a direction of a luminance change with respect to a pixel constituting an image including a component with reference to the pixel. And a second step of performing the processing of the first step on a plurality of pixels in the image.
A step of creating a stitch angle histogram indicating a frequency for each angle from the plurality of angle values obtained in the second step, and a stitch angle histogram obtained in the third step. A component inclination detecting method comprising: detecting a point to determine an inclination of the part; and a first step of detecting the outline of the part and a predetermined interval on the outline of the detected part. And a step of determining an angle between a vector connecting the two points set in the above step and a reference axis. The second step is performed over the entire contour of the component detected in the first step. It is characterized in that it is implemented.

Operation As described above, according to the present invention, the inclination of a component is given by the angle of a straight line portion, so that the inclination of the component is accurately obtained even when the shape of the component is close to a square or when a nozzle partially protrudes from the component. be able to.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

The outlines of many electronic components have linear portions as shown in FIGS. 2A, 2B, 2C, and 2D, and the inclination of the component can be considered to be represented by the inclination of the linear portion in the longitudinal direction of the component. Well, the third
As shown in the figure, an angle θ, which is a reference axis between a vector connecting a point P _A on an arbitrary contour and another point P _B on the contour at a fixed distance from the point, is defined as the angle θ of a point P _C on the contour. When the inclination of the tangent is expressed and the frequency of each angle, that is, the deviation histogram is taken over the entire contour of the part, the angle component appears strongly in a straight line portion where the inclination of the tangent is common as shown in FIG. The peak of the angle of the declination histogram indicates the inclination of the linear portion in the longitudinal direction of the component. When the shape of the outline of the component is a square, it is indistinguishable between the direction orthogonal to the longitudinal direction and the longitudinal direction, but the inclination of the component within 90 ° can be obtained.

On the other hand, the angles formed by the straight lines constituting the contour of the part are known, and most of the angles are 0 °, 90 °, 180 °, and 270 °, and therefore, FIG. As described above, if the deflection angle histogram is divided every 90 °, displaced and accumulated, the inclination can be detected in consideration of all the straight lines.

FIG. 8 is a schematic explanatory diagram of a visual recognition device to which the present invention is applied. The illumination 3 illuminates the electronic component 4 sucked by the suction nozzle 1 under the transmitted light obtained by illuminating the reflection plate 2,
A pattern captured by the TV camera 5 and binarized by the binarization circuit 9 inside the visual recognition device 6 is stored in the image memory 8.
Take in. Subsequent processing is performed by the CPU 9 referring to the image memory.

FIG. 1 is a flowchart relating to the component inclination detecting method of the present invention. Hereinafter, description will be made based on this.

First, the contour of the pattern is detected as a point group, and a coordinate list of the point group forming the contour is created (SP2). Next, over the entire contour of the part (SP3), an argument histogram is created by the following method.

One point on an arbitrary contour and another point separated by a predetermined distance from the point are set from the contour coordinate list (SP4), and the angle between the vectors connecting them and the horizontal axis, that is, the argument is calculated (SP5). ). Now, the argument histogram is obtained by dividing 360 ° into n equal parts (n is an appropriate natural number).
The number of times, ie, the frequency, to which the declination sequentially obtained belongs to each of the sections is obtained. If the declination just obtained is m い ま and the frequency of the kth section is H (k), then H ([mn / 360] +1) ← H ([mn / 360] +1) +1 Addition to the argument histogram is performed (SP6).

Next, in the case where the main straight line constituting the outline of the component is an integral multiple of 90 ° like a square chip, the argument histogram is shown in FIG. 5 (b) at 0 °, 90 °, 180 °, 270 °. The angle histogram is calculated by shifting the angle only (SP
8).

From the declination histogram thus obtained, the center of the section where the sum of the frequencies of 2j-1 sections (j is an appropriate natural number) becomes maximum as shown in FIG. 6 is obtained as the angle peak (SP9). ). Ie Is determined so that is maximized. Finally, in the above section, the center of gravity of the angle is obtained and the inclination can be obtained (SP10).

If the shape of the component is a square, the inclination within 90 ° can be known by shifting and accumulating the declination histogram in units of 90 °.

In addition, when a part of the nozzle protrudes from the part, the nozzle part is generally smaller than the part, and the nozzle shape is usually circular, and as shown in FIG. Is dispersed, the inclination can be detected almost without being affected by the nozzle.

The present invention detects the frequency of the inclination of the vector on the contour,
Since the inclination of the component is given by the angle of the linear portion, the inclination of the component can be accurately obtained even when the shape of the component is close to a right-right shape or when a part of the nozzle protrudes from the component.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a flowchart showing a component inclination detecting method of the present invention, FIG. 2 is a diagram showing a straight line representing the outline and inclination of an electronic component, and FIG. 3 is two points on the outline. Is a diagram showing that a line connecting is parallel to a tangent of a point on a contour, FIG. 4 is a diagram illustrating a case where a declination histogram is created over the entire contour, and FIG. FIG. 6 is a diagram illustrating a method of calculating an angle peak from a declination histogram, FIG. 7 is a diagram illustrating an effect of a nozzle protruding from a declination histogram, FIG. FIG. 8 is a configuration diagram showing one embodiment of an electronic component mounting machine according to the present invention. 1 ... suction nozzle, 2 ... reflector, 3 ... illumination, 4 ...
Electronic parts, 5 TV camera, 6 Visual recognition device, 7
... CPU, 8 ... Image memory, 9 ... Binarization circuit.

 ──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Masamichi Morimoto 1006 Kazuma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (56) References JP-A-61-134880 (JP, A) JP-A-61- 152100 (JP, A) JP-A-60-28298 (JP, A)

Claims (3)

(57) [Claims] A first step of detecting an angle indicating a direction of a luminance change based on the pixel with respect to a pixel constituting an image including a component, and the processing of the first step is performed in the image. A second step performed on a plurality of pixels, a third step of creating a stitch angle histogram indicating a frequency for each angle from the values of the plurality of angles obtained in the second step, and a third step. And a fourth step of calculating the inclination of the component by detecting the maximum point in the knitting angle histogram. The first step is a step of detecting the contour of the component and the step of detecting the outline of the component. A step of setting two points having a predetermined interval on the contour of the part, and a step of determining an angle between a vector connecting the two points set in the step and a reference axis. The second step is a first step. Perform over the entire contour of the detected part. Parts tilt detection method characterized. 2. In a fourth step, in a new stitch angle histogram obtained by displacing the stitch angle histogram in the third step by a predetermined angle and accumulating the same, the inclination of the component is detected by detecting the maximum point. The method for detecting component inclination according to claim 1, wherein the component inclination is obtained. 3. The method according to claim 2, wherein the predetermined angle is set to an integral multiple of 90 degrees.