JPH05215513A - Image center measuring apparatus and fitting apparatus using same - Google Patents

Abstract

PURPOSE:To obtain an image-center measuring apparatus, which can adequately measure the position of the center of an image even if a missing part is present in the image of an object and to obtain a fitting device, which can fit another body into the recess part of one body. CONSTITUTION:An image-center measuring apparatus 10 is constituted of a TV camera 5 and an image processing device 6. The central position is measured for the image part of each lead inserting hole of a substrate 1. A position determining device 4 aligns the position of the lead of an electronic component 2 for the lead inserting hole. Then, a working device 7 inserts the lead of the electronic component 2 into the lead inserting hole. The image-center measuring device 10 performs raster scanning for the image part of the lead inserting hole in the orthognally intersecting two directions and measures the coordinates of the central position. In this measurement, only the measured data for the image part other than the missing part are selected and used for the computation of the coordinates.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for correctly fitting another object into a recess provided on the surface of an object, such as the recess obtained by imaging the object. The present invention relates to an image center measuring device used to measure the center position of an image portion and a fitting device using the device.

[0002]

2. Description of the Related Art For example, when mounting an electronic component on a printed circuit board, at least one of the printed circuit board having the lead insertion hole and the electronic component is guided to a mating member, and the lead of the electronic component is inserted into the lead insertion hole of the printed circuit board. It is being done by aligning and inserting.

FIG. 8 shows a state in which a rod-shaped body 42 having a circular end surface is inserted into a predetermined circular hole 41 provided in a substrate 40. Prior to this insertion work, the substrate 40 is imaged from above by a television camera in a field of view including the circular hole 41 to generate a binary image 43 as shown in FIG. After measuring the center of gravity G1 of the image portion 44 as the image center, the center line of the rod-shaped body 42 is aligned with the center position of the circular hole 41 corresponding to the image center, and the rod-shaped body 42 is inserted into the circular hole 41. To do.

[0004]

However, in this method, when a protrusion such as a burr is present on the peripheral edge of the circular hole 41, a missing portion 45 corresponding to the protrusion is generated in the image portion 44 of the circular hole. The measured center-of-gravity position G2 deviates from the proper center-of-gravity position G1 when there is no protrusion, and it becomes difficult to smoothly insert the rod-shaped body 42 into the circular hole 41, which may lead to damage or deformation of the object. There is.

Also, when the image center is measured from the image obtained by picking up the end face of the rod-shaped body 42, the rod-shaped body 4 is also measured.
If there is a chip on the end face of No. 2, a chip is generated on the image part of the end face of the rod-shaped body. Therefore, the center of gravity position measured in the same way is displaced from the proper center of gravity position when there is no chip, and the circle It is difficult to smoothly insert the rod-shaped body 42 into the hole 41.

The present invention has been made in view of the above-mentioned problems, and image center measurement capable of appropriately measuring the position of the image center even if there is a missing portion in the image obtained by imaging the object. The purpose is to provide a device. Further, according to the present invention, by using the image center measuring device,
It is an object of the present invention to provide a fitting device capable of smoothly fitting the second object into the concave portion provided on the surface of the object.

[0007]

The invention according to claim 1 is an image center measuring apparatus for measuring the center position of an image obtained by imaging an object, wherein
A binarizing circuit for binarizing to generate a binary image;
And a Cartesian coordinate measuring circuit for measuring the center position coordinates of the image portion of the object in the binary image by raster scanning the value image in two orthogonal directions. The Cartesian coordinate measurement circuit, for the image portion of the object on each scanning line, the run length measuring means for selecting and measuring the run length of the image portion excluding the image portion of the defective portion of the object, for each scanning direction, And an arithmetic means for calculating an average value of the coordinates of the center position for all the run lengths for each scanning direction measured by the run length measuring means, as the center position coordinates of the image portion of the object.

According to a second aspect of the present invention, there is provided a fitting device for fitting the second object into the concave portion provided on the surface of the first object, which is obtained by imaging the first object. An image center measuring device for measuring the center position of the image portion of the recess, and a positioning device for aligning the second object with the recess of the first object based on the measurement result by the image center measuring device. And a working device for fitting the second object into the recess of the first object after the positioning by the positioning device. The image center measuring device binarizes a binary image of the input image to generate a binary image, and rasterizes the binary image in two orthogonal directions.
And a Cartesian coordinate measuring circuit for measuring the center position coordinates of the image portion of the concave portion in the value image, wherein the Cartesian coordinate measuring circuit excludes the image portion related to the defective portion of the concave portion for the image portion of the concave portion on each scanning line. Run length measuring means for selecting and measuring the run length of the image portion for each scanning direction, and an average value of the coordinates of the center position of the concave portion for all the run lengths for each scanning direction measured by the run length measuring means. And a calculation means for calculating the center position coordinates of the image portion.

[0009]

The binary image of the input image is raster-scanned in two orthogonal directions, and the run lengths of the image portions of the object on each scanning line except the image portion of the defective portion of the object are scanned. Select and measure for each, and calculate the average value of the coordinates of the center position for all run lengths measured for each scanning direction as the center position coordinates of the image, so even if there are missing parts in the input image , The position of the image center can be measured appropriately. When the object is a recess provided in the object, after properly measuring the center position of the image of the recess, the object is aligned with the recess based on the measurement result and the object is fitted into the recess. So
Smooth fitting is possible, and there is no risk of damage or deformation of the object.

[0010]

1 shows an example in which an image center measuring device and a fitting device according to the present invention are applied to an electronic component mounting device. The electronic component mounting apparatus of the illustrated example is for mounting an electronic component 2 on a printed circuit board (hereinafter referred to as a “board”) 1, and includes a transport mechanism 3, a positioning device 4, a television camera 5, an image processing device 6, and the like. It comprises a working device 7. The board 1 is provided with a plurality of lead insertion holes for inserting the leads of the electronic component 2.

The transfer mechanism 3 positions the substrate 1 by a positioning device 4
It comprises a board-carrying conveyor 8 for carrying in the board, and a board-carrying conveyor 9 for carrying out the board 1 after mounting the components from the positioning device 4.

The television camera 5 and the image processing device 6
Constitutes an image center measuring device 10 for measuring the center position of the image of each lead insertion hole of the substrate 1. The television camera 5 is a CCD camera or the like, and the image processing device 6 includes an image processing unit 11 and a video monitor 12.

The working device 7 is located above the positioning device 4, holds the electronic component 2 by a method such as suction or gripping, and inserts the lead of the electronic component 2 into a predetermined lead insertion hole of the substrate 1. ..

The positioning device 4 includes an XY stage 13
The conveyor 14 is arranged on the upper surface of the. The transfer conveyor 14 is composed of left and right transfer belts, and supports the front and rear of the substrate 1 on a pair of support plates 15 and 15 provided between the transfer belts. The positioning device 4 guides the substrate 1 to the observation position of the television camera 5 and positions each lead insertion hole in the observation field of view of the television camera 5 sequentially, and at the same time, moves the substrate 1 from the observation position of the television camera 5 to the working device 7 The lead of the predetermined electronic component 2 is aligned with each lead insertion hole of the substrate 1 based on the measurement result of the image center measuring device 10 after being moved to the work position.

FIG. 2 shows a circuit configuration of the image processing section 11 of the image processing apparatus 6. The television camera 5 images the substrate 1 from above to generate an input image, and the image processing unit 11 inputs the image signal of the input image and measures the center position of the image portion of each lead insertion hole.

The image processing section 11 includes an A / D converter 2
The A / D converter 20 digitizes analog image signals, and the binarization circuit 21 digitizes the digital signals. The image signal is binarized with a predetermined binarization threshold value to generate a binary image. The image memory 22 stores the binary image on a pixel-by-pixel basis, and the display interface 23 converts the grayscale input image or the binary image into an analog form and outputs it to the video monitor 12 for display.

The microcomputer 24 is for measuring the center of the image and controlling the operation of the positioning device 4 and the working device 7. The CPU 25 is the main body of control and calculation.
And the RO connected to the CPU 25 via the bus 28.
It has M26 and RAM27. Also, the bus 2
The image memory 22 is connected to 8. ROM2
A control procedure by the CPU 25 is programmed and stored in the RAM 6, and data necessary for the CPU 25 to execute the control procedure is written in the RAM 27.

FIGS. 5 and 6 show the principle of measuring the center position of the image portion 30 of the lead insertion hole. The image portion 30 of the lead insertion hole includes a chipped portion 31 due to a burr existing at the opening edge of the lead insertion hole. In the figure, reference numeral 32 is an XY coordinate system set on the image.

In the figure, reference numeral 33 denotes a measurement region set in the image portion 30 of the lead insertion hole. FIG. 5 shows a state in which the measurement region 33 is raster-scanned in the X direction, and FIG. 6 shows this measurement region. The state of raster scanning inside 33 in the Y direction is
Shown respectively. Incidentally, 34 is each scanning line along the X direction, and 35 is each scanning line along the Y direction.

In order to obtain the center position of the image portion 30 of the lead insertion hole, first, the image in the measurement area 33 is scanned in the X direction, and the starting point S and the start point S of the image portion 30 of the lead insertion hole are set for each scanning line 34. Detect each X coordinate X _Sj , X _Ej of the end point E,
The distance between the start point S and the end point E, that is, each scan line 3
Run length L _Xj of the image part 30 of the lead insertion hole on 4
Ask for.

When one run length L _Xj is measured, the X coordinate X _Cj of the center point C of the run length L _Xj is calculated, and the run length L _{X (j-1} on the previous scanning line 34 is calculated. _{) Of} the center point C of X ₎ is compared with the X coordinate X _{C (j-1)} . As a result, if the difference between the two is less than or equal to the predetermined threshold value d, the run length L _Xj and the X coordinate X _Cj of the center point C are registered in one set.

If the difference between the two exceeds a threshold value,
It is judged that the missing portion 31 exists in the image portion 30 of the lead insertion hole, and additionally, the set of registration data so far is for the missing portion 31, or the registration data thereafter is for the missing portion 31. Then, a new set of registration data is generated thereafter.

When a plurality of run lengths are measured on one scanning line, it is judged that the missing portion 31 exists on the scanning line 34, and the measurement data for the scanning line 34 is invalid and is not adopted.

Finally, it is judged which set of registration data is for the image portion 30 of the proper lead insertion hole excluding the missing portion 31, and the image of the lead insertion hole is obtained from the proper set of registration data. The X coordinate X _C of the center position of the portion 30 is calculated.

When the X coordinate X _C of the center position is obtained in this way, the image in the measurement area 35 is then scanned in the Y direction and the same processing is executed.
The Y coordinate Y _c of the center position of 0 is obtained.

FIG. 3 shows the CPU 25 based on the above principle.
The control procedure for measuring the image center by means of step 1 (shown as "ST1" in the figure) to step 18 is shown. First, at the start of the figure, when the substrate 1 is loaded onto the transport conveyor 14 of the positioning device 4 by the transport conveyor 8, the transport conveyor 14 operates to guide the substrate 1 to the observation position of the television camera 5. , XY stage 13 is operated to position the first lead insertion hole within the observation field of view of the television camera 5.

Next, the television camera 5 captures an image of the substrate 1 to generate an input image, and the image signal thereof is taken into the image processing section 11 of the image processing apparatus 6 and the A / D converter 2 is supplied.
The image is digitized by 0, further binarized by the binarization circuit 21, and the binary image is stored in the image memory 22.

Next, in step 1, the CPU 25 sets the counter i for counting the number of the set and the counter j for counting the Y coordinate to "1", and the number of registered data of each set. and sets a counter N _i to "0", further sets "1" (the number of pixels) as the threshold d. The counting and storage of these data are performed using the storage area of the CPU 25 or the RAM 27.

Next, the CPU 25 sets a measurement area for the binary image stored in the image memory 22, and rasterizes the image in the measurement area in the X direction. As a result, Y
When the image portion of the lead insertion hole does not exist on the scanning line whose coordinates are “1” (j = 1), the determination in step 3 is “N”.
It becomes "O" and proceeds to step 14, increments the counter j, returns to step 2 through step 15. Thereafter, the raster scanning is advanced while incrementing the counter j.

In this scanning process, if the starting point S and the ending point E of the image portion of the lead insertion hole are detected on the scanning line of the fifth line (j = 5), for example, the determination at step 3 becomes "YES". , In the next step 4, CP
U25 determines whether or not two or more pairs of these points are detected and the image portion on the scanning line is divided by the missing portion. If the determination is “NO”, the CPU
25 is the difference between the X coordinate X _S5 of the start point S and the X coordinate X _E5 of the end point E, and the run length L _X5 is obtained. The average value X _C5 of the X coordinates X _S5 , X _E5 , that is, the run The X coordinate X _C5 of the center point C of the length L _X5 is calculated.

[0031]

[Equation 1]

In the next step 6, the CPU 25 determines whether or not the data obtained this time is the first one, that is, whether or not the average value has been calculated by the previous scan. The judgment is “NO”, the routine proceeds to step 9, where the counter N _i is incremented, and at the following step 10, the average value X _C5 and the run length L.
_X5 is directly registered in the first aggregation area G (1) of the RAM 27, and the counter j is incremented in step 14.

In the next scanning of the sixth line, the start point and the end point of the image portion of the lead insertion hole are detected, and when these points are a pair, step 3 is "YE".
S ”, step 4 becomes“ NO ”and the process proceeds to step 5, and the run length L _X6 and the average value C _X6 are calculated by the same method.

In the next step 6, since the average value C _X5 has been calculated by the previous scanning, the judgment is "YE".
S ”, the CPU 25 proceeds to step 7 and calculates the absolute value of the difference between the average value C _X6 obtained by the current scanning and the average value C _X5 obtained by the previous scanning, and the calculated value is the above-mentioned value. Is less than or equal to the threshold value d. If the determination is “YES”, the process proceeds to step 9 and the counter N
_i is incremented, and in the following step 10, the average value C _X6 and run length L _X6 are registered in the first aggregation area G (1) of the RAM 27, and in step 14, the counter j is incremented.

If it is assumed that two starting points and two ending points of the image portion of the lead insertion hole are detected in the next scanning of the seventh row, step 3 becomes "YES" and step 4 also becomes "YES". , The first gathering area G
(1) is cleared to data number storage area GR (1) the counter N _i values (in this case "2") writes the counter N _i of, after incrementing the counter i, the process proceeds to scan the next line (Steps 11-14).

When one start point and one end point of the image portion of the lead insertion hole are detected in the scanning of the j-th row, step 3 is "YES" and step 4 is "N".
Then, the run length L _Xj and the average value X _Cj are calculated by the same method. In the next step 6, it is determined that the average value X _{C (j-1)} has been calculated in the previous scan, and the average value X _Cj obtained in the current scan calculated in step 7 and the previous scan When it is determined that the absolute value of the difference from the obtained average value X _{C (j−1)} is larger than the threshold value d, step 8 becomes “NO”, and similarly, the i-th collective area G (i the number of data storage area GR (i) writes the value of the counter N _i) of the counter is cleared N _i, increments the counter i (step 11-13).

By repeating the same procedure while the scanning is in progress, for example, as shown in FIG.
In 7, a plurality of sets of registration data will be generated. Thus, when the scanning of the image in the measurement region is completed, the determination in step 15 is “YES”, and the CPU 2
5 calculates the run length total value for each set, judges that the set of registered data having the maximum total value is for the image portion of the appropriate lead insertion hole excluding the missing portion, and All the X-coordinates X _Cj included in the set are divided by the number of registered data N _i by the formula to calculate the X-coordinate X _C of the center position of the image portion of the lead insertion hole.

[0038]

[Equation 2]

When the X coordinate X _C of the center position is obtained in this way, the image in the measurement area is then scanned in the Y direction and the same procedure is performed to determine the center position of the image portion of the lead insertion hole. The Y coordinate Y _C is obtained. The control procedure for calculating the Y coordinate Y _C is similar to that in FIGS. 3 and 4, and illustration and description thereof are omitted here.

When the center positions of all the lead insertion holes of the substrate 1 are measured in this way, the image processing section 11 operates the transport conveyor 14 of the positioning device 4 to operate the substrate 1.
To the work position. At the working position, the working device 7 holds a predetermined electronic component 2, while the XY stage 13 is driven, and based on the measurement result by the image center measuring device 10, the lead insertion hole of the substrate 1 and the electronic component 2 are The leads of the electronic component 2 are inserted into the lead insertion holes by aligning the leads with each other.

Although the above embodiment calculates the center position of the image portion of the lead insertion hole, the image center measuring apparatus 10 of the present invention is not limited to the image portion of the recess such as the lead insertion hole. It can also be implemented in a device that measures the center position of an image such as a shaft end face. In addition, in the above-described embodiment, the substrate 1
Although the electronic component mounting apparatus inserts the lead of the electronic component 2 into the lead insertion hole of the electronic component, the fitting apparatus of the present invention is not limited to mounting the electronic component, and can insert another object into the recess of an object. Widely applicable to any required device.

[0042]

As described above, according to the present invention, the binary image of the input image is raster-scanned in two orthogonal directions, and the image portion of the target object on each scanning line is excluded. The run length for the image portion is selected and measured for each scanning direction, and the average value of the coordinates of the center position for all the measured run lengths for each scanning direction is calculated as the center position coordinate of the image. Even if the input image has a missing portion, the position of the image center can be properly measured.

When the object is a recess provided in the object, the center position of the image of the recess is measured as described above, the object is aligned with the recess based on the measurement result, and then the object Since it is configured to be fitted into the recess, it is possible to smoothly fit another object into the recess of one object, and there is no risk of damage or deformation of the object, etc. Play.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an overall configuration of an electronic component mounting apparatus embodying the present invention.

FIG. 2 is a block diagram illustrating a circuit configuration example of an image processing unit.

FIG. 3 is a flowchart showing a control procedure of a CPU of an image processing unit.

FIG. 4 is a flowchart showing a control procedure of a CPU of an image processing unit.

FIG. 5 is an explanatory diagram showing the principle of measuring the image center.

FIG. 6 is an explanatory diagram showing a measurement principle of an image center.

FIG. 7 is an explanatory diagram showing registration data in a RAM.

FIG. 8 is a perspective view showing a state where a rod-shaped body is inserted into a circular hole.

FIG. 9 is an explanatory diagram showing a binary image of a circular hole.

[Explanation of symbols]

 4 Positioning Device 5 Television Camera 6 Image Processing Device 7 Working Device 10 Image Center Measuring Device 13 XY Stage 14 Transport Conveyor 21 A / D Converter 24 Microcomputer 25 CPU 26 ROM 27 RAM

Claims (2)

[Claims] 1. An image center measuring device for measuring a center position of an image obtained by picking up an image of an object, wherein the input image is binarized to generate a binary image. A circuit and a Cartesian coordinate measuring circuit that raster-scans the binary image in two orthogonal directions to measure the center position coordinates of the image portion of the object in the binary image. For the image portion of the object on the line, the run length measuring means for selecting and measuring the run length of the image portion excluding the image portion related to the defective part of the object, and the run length measuring means measured the run length. An image center measuring device, comprising: an arithmetic means for calculating an average value of coordinates of a center position for all run lengths in each scanning direction as coordinates of a center position of an image portion of an object. 2. A fitting device for fitting a second object into a concave part provided on the surface of a first object, wherein an image portion of the concave part obtained by imaging the first object. An image center measuring device for measuring the center position of the object, a positioning device for aligning a second object with a concave portion of the first object based on a measurement result by the image center measuring device, and a position by the positioning device And a working device for fitting the second object into the concave portion of the first object after the matching, wherein the image center measuring device binarizes the input image to generate a binary image. And a Cartesian coordinate measurement circuit that raster-scans the binary image in two orthogonal directions to measure the center position coordinates of the image portion of the recess in the binary image. Concave per image part of concave Run length measuring means for selecting and measuring the run lengths of the image parts excluding the image part related to the defective part for each scanning direction, and centering all run lengths for each scanning direction measured by the run length measuring means A fitting device comprising an arithmetic means for calculating an average value of position coordinates as center position coordinates of the image portion of the recess.