KR19990086163A - Image acquisition inspection device using multiple illumination - Google Patents

Abstract

The present invention relates to an image acquisition inspection apparatus using multiple lights, and in the related art, lights installed at two positions of the upper and lower sides are simultaneously projected so that lead portions of components having different heights and angles at the same time exhibit high luminance and not lead portions. As the surface of appears together, the distinction of the lead part is blurred by the brightness difference, the contour is uncertain due to the inconsistency of the focal length on the shape of the lead part, and the division of each part is caused by the increase of the overall brightness of the screen due to the diffusely reflected illumination light. There is a problem that becomes difficult. Therefore, the present invention is composed of three lights (9, 10, 18) having a single optical spectrum and different projection angles to provide a brightness for the component (8), and the image of the component (8) by the illumination unit The monochromatic camera 16 converts and outputs the electrical signal, the image acquisition unit 11 converts and stores the electrical signal output through the monochromatic camera 16 into a binary value, and the stored value of the component 8 The image processing unit 12 for reading the position and the rotation angle, and the controller 13 for transferring or mounting the component in accordance with the reading result, and the two images that are the total reflection light of the light reflected by the lead (LEAD) of the component Combination of to obtain an image with a clear lead boundary, suppresses the image white noise increase (Blow) due to the increase of the overall brightness due to the scattering of the upper and lower illumination, and clarify the lead portion for measuring parts It is to be distinguished.

Description

Image acquisition inspection device using multiple illumination

The present invention relates to an image acquisition inspection apparatus using multiple lights for clearly distinguishing the lead portion for measuring parts, in particular by combining two phases of total reflection light of light reflected from the lead of the metal chain of the component. The present invention relates to an image acquisition inspection apparatus using multiple lights for suppressing an image white noise increase due to an increase in overall brightness due to scattering of upper and lower illuminations, and to increase measurement accuracy by obtaining an image having a distinct lead boundary. .

FIG. 1 is a block diagram of a conventional image acquisition inspection apparatus. As shown in FIG. 1, illuminations 9 and 10 that provide brightness of a component to facilitate image acquisition and an imaging device are used. A camera 16 for converting and outputting an image of a component into an electrical signal, an image acquisition unit 11 for converting and storing an image signal converted into an electrical signal output from the camera 16 into an appropriate binarization value; Image processing unit 12 for reading the position and rotation angle of the part by the value stored in the image acquisition unit 11 by performing a variety of algorithms, and the image processing unit 12 when transferring and mounting the part to the corresponding assembly position It is composed of a controller 13 for transporting or mounting by using the position and the rotation angle of the component read in the).

As shown in FIG. 2, the image acquisition unit 12 includes an analog / digital converter 11a for converting and outputting an electrical signal transmitted through the camera 16 into a digital value, and the analog / digital converter. It consists of a memory 11b which stores the digital value output from the converter 11a.

Looking at the prior art configured as described above is as follows.

When the nozzle 7 mounted on the head portion of the surface mount assembly apparatus 1 picks up the component 8 and moves to the upper portion of the inspection portion, the illuminations 9 and 10 of the image acquisition inspection apparatus are applied to the component 8. Adjust the brightness for

At this time, the camera 16 photographs the state in which the component 8 is attached to the nozzle 7 as a still image, and provides this information to the image acquisition unit 11.

Then, as shown in FIG. 2, the image acquisition unit 11 converts an analog signal for an image of a component into a digital value and stores it in the memory 11b.

In most cases, the information converted to digital values divides the brightness of each pixel by 256, and the number of pixels varies according to the system configuration.

The image processor 12 reads data stored in the memory 11b of the image acquisition unit 11, reads the position and rotation angle of the component of the component 8, and provides the same to the controller 13.

Then, the controller 13 transfers or mounts the components using the position and rotation angle of the components read by the image processor 12 when the components are transferred and mounted to the corresponding assembly position.

The image processor 12 processes using an algorithm, which includes a histogram, a projection, a rotation, a matching, a convolution, an edge detection, and the like. There is this.

In acquiring an image of the component 8, the portion that provides an important clue for extracting the positional information of the component 8 is, as shown in FIG. 3, a lead 17 (LEAD) portion for electrical connection of the component 8. The reason for this is to use the pad-type standard for PCB board design uniformity, because the lead position of the part that comes into contact with the pad must be precisely managed.

Due to problems in the specification and processing of the lead (LEAD), a lead shape having an exact right angle cannot be made, or the lead shape itself may be curved. For example, as shown in FIG. 3, in the case of the QFP type, the C, D, and E regions are measured, but the C and E regions have a rounded shape, and the B region is not vertical, and the A region is not the measurement target.

Herein, a process of acquiring an image of a part of the lead 17 of the component 8 will be described. In FIG. 1, when the lower illumination 9 is used in a direction parallel to the camera 16, the projection light direction is illustrated in FIG. 4A. Is equivalent to "a" in.

At this time, the direction of the reflected light reflected from the lead 17 of the component 8 is largely divided into two types, as shown in FIG. 4A as "b" and "c". That is, the light path "b" which is directly reflected by the camera 16 is divided into the light path "c" which does not enter the camera 16.

The image projected on the camera 16 by the optical paths " b " and " c " as described above is extracted in the form as shown in Fig. 4B.

At this time, the interface information of the lead 17 to be extracted is poor.

To compensate for this, the upper light 10 is used. When the upper light 10 is used, the projection light direction is as shown in FIG. 5A.

Then, the direction of the reflected light reflected from the lead 17 portion of the component 8 is reflected as shown by "b" and "c" in FIG. 5A, and the amount reflected by the camera 16 increases.

As such, when both the upper and lower lights 10 and 9 are used, the image projected by the camera 16 is as shown in FIG. 5B.

As described above, when the upper light 10 and the lower light 9 are projected onto the lead 17 portion of the component 8, the light is reflected from the lead 17 portion of the component 8 so that the camera ( 16), the camera 16 reads the projected image and transmits it to the image acquisition unit 11 accordingly.

Then, the position and rotation angle of the component of the component 8 are read through the image acquisition unit 11, the image processing unit 12, and the controller 13, and the assembly of the component 8 is assembled according to the read result. Transfer to position and mount.

However, in the prior art as described above, the illumination installed at two positions up and down is simultaneously projected so that the lead portions of the parts having different heights and angles simultaneously exhibit high luminance, and the surface of the component plastic package, not the lead portions, appears together. As the division of the lead portion through the car is ambiguous, the contour is uncertain due to the focal length mismatch of the shape of the lead portion, and as the size of the component increases as shown in FIG. 6, the position of the lead is not collinear with the camera. This leads to the bending of the lead, which increases the complexity of the algorithm for determining the position of each lead and causes errors, and increases the effect of diffuse reflection due to the simultaneous projection of light from multiple directions instead of unidirectional rays. (blow) causes the interface to be inaccurate, worsening the accuracy Key has a problem.

Accordingly, an object of the present invention for solving the conventional problems as described above is to provide an image acquisition inspection apparatus using multiple illumination for suppressing the increase in image white noise due to the increase in the overall brightness due to the scattering of the upper and lower illumination.

Another object of the present invention is to provide an image acquisition inspection apparatus using multiple lights for clearly distinguishing the lead portions for component measurement.

Another object of the present invention is to reduce the sensitivity (exposure) so that the camera can detect only the reflected light from the metal lead, not diffuse reflection, and the image having a distinct lead boundary by combining the two images by the upper light and the lower light The present invention provides an image acquisition inspection apparatus using multiple lights.

1 is a block diagram of a conventional image acquisition inspection apparatus.

2 is a detailed block diagram of an image acquisition unit in FIG. 1;

3 is an enlarged view of a part in FIG. 1;

4A is an explanatory diagram showing the direction of reflected light when only the lower illumination is used in FIG. 1;

4B is an image projected on the camera in FIG. 1 when only lower illumination is used.

FIG. 5A is an explanatory diagram showing the direction of reflected light when the upper and lower illuminations are used simultaneously in FIG. 1; FIG.

5B is an image projected on the camera in FIG. 1 when the upper and lower illuminations are used simultaneously.

6 is an explanatory diagram showing an imaging angle of a camera with respect to a lead position of a part;

FIG. 7A is an explanatory diagram showing the direction of reflected light when the upper lighting is used in FIG. 1; FIG.

7B is an image projected on the camera in FIG. 1 when only the top light is used.

8 is a block diagram of an image acquisition inspection apparatus using multiple lights of the present invention.

FIG. 9 is the first embodiment of the image acquisition unit in FIG. 8; FIG.

FIG. 10 is a second embodiment of an image acquisition unit in FIG. 8; FIG.

FIG. 11 is a detailed configuration diagram of the image preprocessor of FIG. 10.

12A is a diagram of a fiducial mark for setting a reference point on a PCB substrate.

12B is a block diagram of an image acquisition inspection apparatus for measuring a fiducial mark.

Explanation of symbols on the main parts of the drawings

8: parts 9,10,18: lighting

11: image acquisition unit 12: image processing unit

13 controller 16 camera

19: preprocessing image storage device 20: preprocessing logic unit

21: analog-to-digital converter 22: lookup table

23 ~ 25: image storage device 33: end gate

34: Oagate 35: Exclusive Oagate

In order to achieve the above object, the present invention comprises a lighting unit having a single optical spectrum and having three projection angles different from each other to provide brightness for a component, and converting an image of the component by the lighting unit into an electrical signal and outputting a single color. A camera, an image acquisition unit for converting and storing an electrical signal output through the monochrome camera into a binarization value, an image processing unit for reading the position and rotation angle of the part with the stored value, and transferring the part according to the reading result. It is characterized by consisting of a controller for mounting.

In addition, the present invention comprises a lighting unit having a multi-optical spectrum and two or more lights having different projection angles to provide brightness for the component, a color camera for converting the image of the component by the lighting unit into an electrical signal and outputting the above; An image acquisition unit for converting and storing an electrical signal output through a monochrome camera into a binarization value, an image processing unit for reading the position and rotation angle of the part using the stored value, and a controller for transferring or mounting the part according to the reading result. Characterized in that configured.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 8 is a block diagram of an apparatus for inspecting an image acquisition using multiple lights according to the present invention. As shown in FIG. 8, a component 8 includes three illuminations 9, 10, and 18 having a single optical spectrum and different projection angles. And a lighting unit for providing brightness for the light emitting unit, a monochrome camera 16 for converting an image of the component 8 by the lighting unit into an electrical signal, and outputting the electrical signal output through the monochrome camera 16. An image acquiring unit 11 for converting and storing the value, an image processing unit 12 for reading the position and rotation angle of the component 8 with the stored value, and a controller 13 for transporting or mounting the component according to the read result. ).

The image acquisition unit 11 converts the analog signal of the image of the lead portion of the component into a digital signal, as shown in FIG. 9, and converts the digital signal for each illumination through an internal lookup table. An analog / digital converter 21 which separates and outputs a luminance signal according to a spectral composition, an image storage device which stores signals separated for each illumination through the analog / digital converter 21, and the analog / digital converter A preprocessing logic unit 20 which combines the signals separated through 21 to obtain an image having a distinct read boundary; and a preprocessing image storage device which stores data about an image obtained through the preprocessing logic unit 20 ( 19).

In addition, as shown in FIG. 10, the image acquisition unit 11 separates the three primary colors of the image of the lead portion of the component and converts the analog signal for the three primary colors into a digital signal (RGB). And a lookup table 22 for separately outputting the luminance signals F1, F2, and F3 for the three primary color digital signals output from the analog / digital converter 21 and the lookup table 22, respectively. An image storage device 23 to 25 for storing the output luminance signal, a preprocessing logic unit 20 for combining the signals separated by the analog / digital converter 21 to obtain an image having a distinct read boundary; And a preprocessing image storage device 19 for storing data about an image obtained through the preprocessing logic unit 20.

And, as shown in Figure 11, the pre-processing logic unit, two look-up tables 31 and 32 for outputting the level values for the two optical signals totally reflected among the light reflected from the lead of the component, and An AND gate 33 for obtaining a minimum value by ANDing the signals output from the two lookup tables, an ora gate 34 for obtaining the maximum value by ORing the two signals, and an exclusive OR of the two signals. Exclusive orifice 35 for ringing to obtain a difference value, and selector switch 21 for selecting and outputting one of the outputs of the AND gate 33, the oragate 34, and the exclusive oragate 35. It consists of.

Referring to the operation and effect of the present invention configured as described in detail as follows.

As shown in FIG. 7A, when only the top light 10 is used, the projection light direction is the same as in “d”, and the direction of the reflected light reflected from the lead 17 portion of the component 8 is directly reflected by the camera 16. The optical path "b" is divided into the optical path "c" that does not properly enter the camera 16.

Since the interface of the lead 17 of the component 8 cannot be completely perpendicular to each other, reflection occurs at the interface or curved surface due to the illumination of the "d" direction with a small angle to the horizontal line. Due to its characteristics, it exhibits total reflection tendency like a mirror.

That is, very high luminance is shown during camera imaging.

The image projected on the camera 16 by the optical paths "b" and "c" is extracted in the form as shown in FIG. 7B.

Such characteristics are also shown in the conventional optical system, and the above problems are solved by using a form that is not overlapped as compared to that used as it is.

That is, the image shown in the form of FIG. 4B and the image shown in the form of FIG. 7B are arranged to be different from each other since the incident angles are greatly different (about 90 degrees) from each other. In other words, when only the lower light 9 is incident, the brightest part appears dark when only the upper light 10 is incident, and vice versa.

Therefore, by reducing the sensitivity (exposure) so that only the reflected light from the metallic lead, not the diffuse reflection, can be detected by the camera 16, an image having a distinct lead boundary can be obtained by combining these two images.

In addition, since each image has a light projection angle, the accuracy of the image processing algorithm may be improved by using the image processing algorithm.

When the nozzle 7 mounted on the head of the surface mount assembling apparatus 1 of FIG. 8 adsorbs the component 8 and moves to the upper portion of the inspection unit, the projection linearity is good and is applied to the component 8 and the camera 16. Illuminations 9, 10, 18 having different angles of incidence with respect to the light control the brightness of the component 8.

Then, the camera 16 photographs the state in which the component 8 is attached to the nozzle 7 as a still image, and provides this information to the image acquisition unit 11.

Then, as shown in FIG. 9, the image acquisition unit 11 converts the analog signal for the image of the component 8 into a digital value, respectively, and converts the converted signal into an internal lookup. The illuminations 9, 10, and 18 are separated (F1, F2, F3) according to the optical spectrum composition and stored in the image storage devices 23 to 25 through the table.

Accordingly, the luminance signal for each illumination is separated according to the optical spectrum, and it is possible to separately acquire information of an image according to different illumination angles by one imaging.

9 has a single optical spectrum and uses a monochrome camera.

At this time, the preprocessing logic unit 20 is the luminance signal (F1, for the total reflection light of the light reflected from the metal chain lead 17 of the luminance signal (F1, F2, F3) separated by the analog / digital converter 21) F2) is input to obtain an image having a clear lead boundary using logic gates.

The image thus obtained is stored in the preprocessing image storage device 19.

Then, the image processing unit 12 reads the luminance signals stored in the image storage devices 23 to 25 of the image acquisition unit 11 by using an algorithm, and also stores the values stored in the preprocessing image storage device 19. Is read and the position and rotation angle of the parts of the parts 8 are read and provided to the controller 13.

Then, the controller 13 transfers or mounts the components using the position and rotation angle of the components read by the image processor 12 when the components are transferred and mounted to the corresponding assembly position.

The image acquisition unit 11 separates the analog signal for the image of the component 8 into three primary colors (red, green, blue) in its analog / digital converter 21, as shown in FIG. Each of the separated three primary colors is converted into a digital value, and then converted into the converted digital signal RGB to be provided to the lookup table 22.

Then, the luminance signals F1, F2, and F3 corresponding to the digital signals R.G.B converted in the lookup table 22 are found and stored in the image storage devices 23 to 25, respectively.

At this time, the pre-processing logic unit 20 is applied to the total reflection light of the light reflected from the metal chain lead 17 among the luminance signals F1, F2, and F3 converted through the analog / digital converter 21 and the lookup table 23. The luminance signals F1 and F2 are input to obtain an image having a clear lead boundary using logic gates.

The image thus obtained is stored in the preprocessing image storage device 19.

Then, the image processing unit 12 reads the luminance signals stored in the image storage devices 23 to 25 of the image acquisition unit 11 by using an algorithm, and also stores the values stored in the preprocessing image storage device 19. Is read and the position and rotation angle of the parts of the parts 8 are read and provided to the controller 13.

Then, the controller 13 transfers or mounts the components using the position and rotation angle of the components read by the image processor 12 when the components are transferred and mounted to the corresponding assembly position.

Here, with reference to FIG. 11, the preprocessing logic unit 20 is reflected from the metal chain lead 17 among the luminance signals F1, F2, and F3 converted by the analog / digital converter 21 in FIG. 9. The luminance signals F1 and F2 for the total reflection light of the received light are accepted or the luminance signals F1, F2 and F3 for the three primary colors R and GB are output from the lookup table 22 in FIG. 10. Accept the luminance signals F1 and F2 for total reflection light reversed from (17).

The look-up tables 31 and 32 thus received output a signal indicating whether they are high potential values or low potential values with respect to the input luminance signals F1 and F2, respectively.

Then, the AND gate 33 obtains the minimum value among the input values by ANDing the values output from the lookup tables 31 and 32, and the orgate 34 outputs the values from the lookup tables 31 and 32. The maximum value of the input values is obtained by ORing, and the exclusive orifice 35 obtains the difference between the input values by exclusively ringing the values output from the lookup tables 31 and 32, respectively, and selecting switches. Provided by 36.

Accordingly, the selection switch 36 selects the values made by the AND gate 33, the OA gate 34, and the exclusive OA gate 35 one by one, and switches them to the preprocessing image storage device 19 to store them.

Then, the values stored in the preprocessing image storage device 19 are used as calculation data of the image processor 12.

For example, when the images according to the lower light 9 and the upper light 10 of FIG. 8 are separately acquired, the image by the lower light 9 is as shown in FIG. 4B, and the image by the upper light 10 is shown in FIG. 7B. When the two images shown in this way are subjected to exclusive oaring by using the exclusive oar gate 35 for each pixel, the parts of the parts differ in luminance with respect to the lower light 9 and the upper light 10. Only large areas will be strengthened.

This is enhanced by the boundary portions C and E of the lid 17, which appear dark for the lower light 9 and bright for the upper light 10, and also bright for the lower light 9 and the upper light 10 ) Results in the darker area (D area) being enhanced.

As shown in FIG. 8, the upper light 10 is not high due to the position of the component 8, and the projection angle is slightly upward. This light is reflected by the region B of the lead 17 and the surface of the component package. The luminance of the area A of (17) is increased.

Therefore, even when only the upper light 10 is used, the luminance of the area A is stronger than that of the area D. Therefore, the relative difference is reduced, which is suppressed when the processing is performed using the exclusive oar 35, and the area B is also used for both cases. The luminance appears similar in the small direction (the difference is smaller), which is also suppressed.

In addition, the reflected light of the component package portion which increases the luminance of the entire image and the diffusely reflected light due to the peripheral reflection are also suppressed because the luminance difference is reduced, thereby obtaining a more pronounced lead image of the component, thereby improving measurement accuracy.

In this way, the illumination treatment targets total reflection light (“b” in FIG. 4A and “c” in FIG. 4A) of light reflected from the lead 17 of the metal chain, and has an advantage of weakly applying the sensitivity requirement of the measurement camera. Can be obtained.

In addition, there is a fiducial mark that sets a reference point for the PCB substrate as a location inspection target for the surface mount assembly equipment.

Fuducial marks are processed together with pads on the PCB and the material is copper, and the shape has various shapes (circles, rectangles, triangles, stars, crosses, etc.) as shown in FIG.

In order to measure the fuducial mark, an image acquisition inspection apparatus is also used, and thus, the method used in the present invention may be used, and various approaches may be made to changes in reflectance due to variations in PCB fabrication.

When using the same structure as in FIG. 10 using a color camera, the color difference, not just the simple reflectance variation of the copper plate of the Fuducial mark and the PCB base plate, can be used as the information for boundary separation, and as shown in FIG. It is possible to construct an image acquisition inspection equipment that is resistant to disturbances.

Therefore, the present invention combines the two phases of the total reflection light of the light reflected from the lead of the metal chain of the component to obtain an image having a distinct lead boundary, the image white noise according to the increase in the overall brightness due to the scattering of upper and lower illumination There is an effect that suppresses blow and makes it possible to clearly distinguish the lead part for measuring parts.

Claims (7)

A lighting unit that provides brightness for the component, a camera that converts and outputs an image of the component into an electrical signal, an image acquisition unit that converts and stores the electrical signal into a binarization value, and a position and rotation of the component with the stored values. An image acquisition inspection apparatus comprising an image processing unit for reading an angle and a controller for transferring or mounting a part according to the reading result, wherein the illumination has a single optical spectrum and includes two or more illuminations having different projection angles. Image acquisition inspection apparatus using multiple lights characterized in that. The image acquisition inspection apparatus using multiple lights according to claim 1, wherein the camera uses a monochrome camera. The image acquisition unit of claim 1, wherein the image acquisition unit converts an analog signal of an image of a lead part of the component into a digital signal, and outputs the digital signal by dividing the digital signal into a luminance signal according to an optical spectrum composition for each illumination through an internal lookup table. An analog / digital converter, an image memory device for storing signals separated for each illumination through the analog / digital converter, and a signal separated through the analog / digital converter to obtain an image having a distinct lead boundary. And a preprocessing logic unit configured to store a data of an image obtained through the preprocessing logic unit. 4. The preprocessing image storage device according to claim 3, wherein the preprocessing image storage device receives two lookup tables for outputting level values for two optical signals totally reflected among the light reflected from the lead of the component, and a signal output from the two lookup tables. An AND gate which obtains a minimum value by ringing, an OA gate that obtains a maximum value by oring the two signals, an exclusive oragate which obtains a difference value by performing an exclusive operation on the two signals, and the AND gate An image acquisition inspection apparatus using multiple lights, characterized in that the selection switch for selecting and outputting one of the output of the oragate and the exclusive oragate. A lighting unit that provides brightness for the component, a camera that converts and outputs an image of the component into an electrical signal, an image acquisition unit that converts and stores the electrical signal into a binarization value, and a position and rotation of the component with the stored values. An image acquisition inspection apparatus comprising an image processing unit for reading an angle and a controller for transferring or mounting a part according to the reading result, wherein the illumination has multiple optical spectra and includes two or more illuminations having different projection angles. Image acquisition inspection apparatus using multiple lights characterized in that. 6. The image acquisition inspection apparatus using multiple lights according to claim 5, wherein the camera uses a color camera. 6. The image acquisition unit according to claim 5, wherein the image acquisition unit separates the three primary colors of the image of the lead portion of the component and converts the analog signals for the three primary colors into digital signals, and the three primary color digital signals output from the analog / digital converters. A lookup table that separates and outputs a luminance signal for the output signal, an image memory device for storing the luminance signal respectively output from the lookup table, and a signal separated by the analog / digital converter are combined to form an image having a distinct lead boundary. And a preprocessing image storage device for storing data about an image obtained through the preprocessing logic unit.