JP2818347B2 - Appearance inspection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an appearance inspection apparatus for inspecting the appearance of a work such as an electronic component, and more particularly to an appearance inspection apparatus capable of diversifying the appearance of the main surface of a work.

[0002]

2. Description of the Related Art As an appearance inspection apparatus for inspecting the appearance of a work, an apparatus for performing image processing is conventionally known.
For example, there is known an appearance inspection apparatus that inspects the appearance of the upper surface and the side surface of a work by using one camera for photographing the upper surface of the work and one camera for photographing the side surface of the work. This appearance inspection device illuminates the upper surface and the side surface of the work with an illumination device.

[0003]

However, since only the top and side surfaces of the work are illuminated, the number of items that can be determined by image processing is small, and the inspection items are limited. Further, since two cameras are used, the camera becomes expensive. Therefore, if only one camera is used and only a surface in one direction of the work is inspected, the number of items that can be inspected further decreases.

It is an object of the present invention to provide a visual inspection apparatus capable of inspecting more detailed external elements at once by using only one camera.

[0005]

In order to solve the above-mentioned problems, a visual inspection apparatus according to the present invention includes a first illuminating device for illuminating a main surface of a work from an X-axis direction which is a substantially normal direction thereof. A second illumination device that illuminates an end surface orthogonal to the main surface of the work from the Y-axis direction, and a third illumination device that diffusely illuminates one side surface orthogonal to the main surface of the work from the Z-axis direction. An imaging means for simultaneously capturing, via an optical system, the main surface of the work and the other side opposite to the one side of the work as a reflection image and a silhouette image separated on one imaging screen, and illuminating the one surface of the work; And a first lighting device.

In the present invention, the main surface of the work is photographed as a reflection image by the first lighting device, but the other side surface of the work is photographed as a silhouette image by the third lighting device. The surface irregularities of the main surface are raised clearly and darkly as a silhouette contour of the silhouette image, and the illuminating light from the second illumination device is strongly reflected at the ridgeline portion on the main surface of the work, so that this is clearly captured in the reflected image. You. By simply photographing the main surface of the work as a reflection image or a silhouette image, the contour of the main surface of the work can be clearly captured, but not the surface irregularities or ridges within the main surface of the work. However, according to the present invention, not only the contour of the main surface of the work, but also surface irregularities and ridges within the main surface of the work can be clearly captured on one imaging screen. And many items can be inspected at once.

In particular, the appearance inspection apparatus according to the present invention is characterized by the following image processing means.

[0008] The image processing means includes an image cutout means for cutting out a first image area containing only the reflection image of the main surface and a second image area containing only the silhouette image of the other side face on the imaging screen; A luminance distribution of the first image area is created based on the pixel data in the first image area, and a first binarization threshold corresponding to the first luminance distribution is extracted,
A binarization threshold value extracting unit configured to generate a luminance distribution of the second image region based on the pixel data in the second image region and extract a second binarization threshold value according to the second luminance distribution; 1 of 2
The pixel data in the first image area is binarized using the binarization threshold to obtain a first binarized image, and the pixel data in the second image area is binarized using the second binarization threshold. Binarization processing means for obtaining a second binarized image, and appearance determining means for judging the quality of the appearance of the main surface and the other side of the work based on the first and second binarized images And characterized in that:

Although a reflection image of the main surface and a silhouette image of the other side are separately included on one imaging screen captured by the imaging device, first, only the reflection image of the main surface is extracted by the image extracting means. The image is cut out into a first image area including the first image area and a second image area including only the silhouette image on the other side. Next, a binarization threshold extracting unit creates a luminance distribution of the first image region based on the pixel data in the first image region, and extracts a first binarization threshold according to the luminance distribution. And a luminance distribution of the second image area is created based on the pixel data in the second image area, and a second binarization threshold corresponding to the luminance distribution of the second image area is extracted. Here, the reason why the unique binarization threshold values are extracted is that the illumination means is different. Thereafter, the binarization processing unit binarizes the pixel data in the first image area with the first binarization threshold to obtain a first binarized image, and performs the second binarization with the second binarization threshold. Pixel data in the two image areas are binarized to obtain a second binarized image. Then, the appearance determining means determines the quality of the appearance of the main surface and the other side of the work based on the first binarized image and the second binarized image.

As described above, according to the present invention, the first image area containing only the reflection image of the main surface and the second image area containing only the silhouette image on the other side are cut out and separated, and each image area is separated. After deriving a binarization threshold corresponding to the unique luminance distribution of the above, the binarization processing of the image area is executed using the unique binarization threshold, respectively. The images can be subjected to the optimal binarization processing, and the contours of the main surface as well as the details such as surface irregularities and ridges in the main surface of the work can be clearly identified, and more inspection items can be obtained. Can be inspected accurately.

In particular, since the reflected image of the main surface of the work includes a high-luminance ridge portion by the second illumination device, a high-luminance region corresponding to the reflected image in the luminance distribution of the first image area. Is shifted to higher brightness and emphasized,
The base of the luminance distribution is clarified, the extraction of the first binarization threshold value becomes easy, and the binarization processing of the first image area becomes appropriate. In addition, the base of the luminance distribution of the second image region including the silhouette image is clear, so that the second binarization threshold can be easily extracted, and the binarization process of the second image region is appropriate.
Therefore, more fine appearance elements in the main surface of the work can be inspected more at once.

Further, the present invention comprises a work transfer means for transferring a work to a test position along a work transfer path, and discharging the work from the test position after the test, wherein the first, second and third illuminations are provided. Either of the devices is disposed in the work transport path, and includes an illumination device drive unit for moving forward and backward the illumination device disposed in the work transport path. When the illumination device is transported to the inspection position, the illumination device is retracted from the work transport path to allow the workpiece to pass, and the illumination device is moved forward after passing the workpiece. Even in a structure in which the illumination devices are arranged in the X, Y, and Z axis directions, interference between the loading / unloading of the work and the illumination devices can be prevented.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

FIG. 1 is a front view schematically showing a main part of an embodiment of an appearance inspection apparatus according to the present invention, and FIG. 2 is a side view thereof.

In the figure, a work 3 is arranged below a lens 2A of a camera 2 connected to an image processing means 1. The work 3 used in the description of the present embodiment is a lead wire 3
b is a crimp terminal integrally formed. Three illumination devices, that is, a ring illumination device (first illumination device) 4, a transmission illumination device (third illumination device) 5, and a fiber illumination device (second illumination device) 6 are provided so as to surround the work 3. Have been. Further, a reflection mirror 7 is provided opposite to the transmission illumination device 5 with the work 3 interposed therebetween.

The ring illuminator 4 is provided directly below the camera 2 and irradiates the upper surface (main surface) of the work 3 from the X-axis (vertical) direction, which is a substantially normal direction. A reflection image of the work 3 is taken through the central opening of the work 4.

The transmissive illumination device 5 diffuses and illuminates one side surface orthogonal to the upper surface of the workpiece 3 from the horizontal Z-axis direction. The transillumination reflection mirror 9 reflects illumination light from the illumination source 8; It is composed of a diffusion plate 10 such as an opal glass for diffusing light from the reflection mirror 9 for transmitted illumination. The transmissive illumination device 5 projects the diffused light from the diffuser plate 10 onto one side of the work 3 and projects the other side opposite to the one side onto the reflection mirror 7 as a silhouette image. The silhouette image projected on the reflection mirror 7 is reflected in the direction of the camera 2. The transmitted illumination device 5 can be moved up and down by a cylinder 11 (illumination device driving means). The fiber illuminating device 6 is for illuminating the end face of the workpiece 3 orthogonal to the upper surface in a horizontal Y-axis direction.

The work 3 is transferred by the work transfer means 12 along the work transfer path 13 to the inspection position (the position of the work 3 in FIG. 1). The work transporting means 12 includes the driving means 1
4 and a clamp 15 movable by the driving means 14 in the direction A of FIG. 2 and the direction along the work transfer path 13 of FIG. Work 3 is lead wire 3
b is clamped by the clamp 15 and transported to the inspection position along the workpiece transport path 13 from the right side in FIG.
Since the transmitted illumination device 5 is located on the work transfer path 13, when the work 3 is transferred to the inspection position, it is retracted downward by the cylinder 11, and is advanced upward after passing the work 3. After the inspection of the work 3 is completed, the work 3
Is moved leftward in FIG. 2 by the work transport means 12 and is discharged. Note that the image processing means 1 is connected to the monitor 17.

FIG. 3 is a view showing an image photographed by the camera 2. In one image, a reflection image 18 on the upper surface of the work 3 and a siliette on the other side of the work 3 reflected from the reflection mirror 7 are shown. An image 19 is included. The reflection image 18 on the upper surface is formed by ridge lines 18A and 18B of a surface (including the end surface itself) viewed from the end surface side by illumination from the fiber illumination device 6.
Is clearly photographed. Therefore, it is possible to accurately inspect the case of the work 3 having an inspection item in a part such as an end face and other ridge lines.

The images 18 and 19 are processed by the image processing means 1 as described later, and various inspections are performed.

FIG. 4 is a front view showing the entire appearance inspection apparatus, and FIG. 5 is a side view thereof. The illustration of the image processing means 1 and the monitor 17 is omitted. Post 2 on base 20
1 and the cylinder support frame 22 are fixed. The upper arm 23 is attached to the upper end of the support 21, and the camera 2 is fixed to the upper arm 23. A lower arm 24 is mounted near the center of the column 21, and a frame 25 is fixed to the lower arm 24 and the upper arm 23. The ring lighting device 4 is attached to this frame 25 via a fixture 26.
However, the fiber illuminating device 6 is fixed via the fixture 27, and the reflection mirror 7 is fixed via the fixture 28.
The cylinder 11 and the illumination source 8 are fixed to the cylinder support frame 22.

FIG. 6 is a functional block diagram of the image processing means 1. The video signal from the camera 2 is, for example, 512 ×
The A / D conversion means 30 converts the signal into, for example, an 8-bit signal per pixel. The digitally converted signal is taken into the memory 31.

Since the video signal from the camera 2 includes the reflection image 18 on the upper surface and the siliette image 19 on the other side, an area designation memory 32 is provided to divide these two images. As shown in FIG. 7, the area designation memory 32 is for storing cutout area designation data of the corner positions P1 to P4 and Q1 to Q4 so as to include the two images 18 and 19, respectively. . The description of the method for determining the position data is omitted.

The data transfer means 34 in the control means 33
The control section 33 reads out the specified data of the corner from the area specifying memory 32, and divides the data of the two images 18 and 19 from the image data taken into the memory 31 based on the position of the corner. That is, a first image area including only the reflection image 18 and a second image area including only the silhouette image 19 are cut out on the imaging screen. The area designation memory 32, the control means 33, and the memory 31 constitute an image cutout means. The data of the two divided image areas is individually sent to the luminance distribution extracting unit 35.

The reason why the two images 18 and 19 are divided and sent separately to the luminance distribution extracting means 35 is that each image is illuminated by a different illumination device, so that the threshold value for binarization is used. (Binarization level).

The brightness distribution extracting means 35 has a memory 35a for temporary storage. The brightness distribution creating means 35 creates a brightness distribution of each pixel for each of the images 18 and 19.
FIG. 8 shows a histogram of the luminance distribution 18 of the image area including the reflection image and the luminance distribution 19 of the image area including the silhouette image. In the figure, the horizontal axis is luminance, the vertical axis is the number of pixels,
In the luminance distribution 18K of the reflection image 18 on the upper surface, pixels are distributed over each luminance level. However, since the reflection image 18 includes a high-luminance ridge line portion, it exhibits a mountain-shaped distribution in a high-luminance region. ing. The high-brightness mountain-shaped portion is a reflection image 18.
This is the top surface of the work inside. Silhouette image 1 on the other side
Since the luminance distribution 19K of No. 9 is a silhouette image, the image itself is sharply distinguished between light and dark, and thus the luminance distribution has a mountain shape at two high and low places. The silhouette image 19 is the Yamagata part on the low frequency side
It is the other side part of.

This luminance distribution is obtained by binarizing level extracting means 36.
Sent to The binarization level extraction means 36 has a memory 36a for temporary storage. This binarization level extraction means 36
Determines the binarization level based on the luminance distribution. This determination method is, for example, a method using the median value of the luminance distribution as a threshold value, or the maximum luminance of 60
For example, a method using% as a threshold can be adopted. In addition, it is also possible to instruct which method is to be adopted from outside the control means 33 or the like.

The reason why the binarization level can be determined from such a luminance distribution is that the mountain shape distribution on the high frequency side of the reflection image 18 and the mountain shape distribution on the low frequency side of the silhouette image 19 are clear. In particular, since a high-luminance ridge portion is included in the reflection image 18 by the fiber illuminating device 6, the mountain shape distribution on the high frequency side of the reflection image 18 is emphasized on the higher frequency side. The parts are clarified.

The signal from the luminance distribution extracting means 35 is sent to a binarizing means 38. After the image data in the memory 31 is divided into two images 18 and 19, each image data is conveyed to the binarization processing unit 38 by the data transfer unit 34. The binarization processing means 38 performs binarization processing on each of the images 18 and 19 using the above-mentioned binarization level as a threshold value.

The binarized data is stored in a binarization memory 37.
Is stored in This binarization memory 37 is a first binarization memory 37 for storing data of the reflection image 18 on the upper surface.
A and a second binarized memory 37B for storing data of the silhouette image 19 of the side surface.

FIG. 9 is a flowchart of the procedure performed by the image processing means 1.

After the A / D conversion of the video signal from the camera 2 in step S1, the video signal is taken into the memory 31 in step S2. In step S3, the reflection image 18 on the upper surface of the work 3 and the silhouette image 19 on the other side are divided. Next, in step S4, a luminance distribution is extracted, and in step S5, a binarization level is extracted. In step S6, the data of each image is binarized. In step S7, the appearance of the work 3 is inspected based on the binarized data. In this inspection, after the reference position of each image is determined, the position of each part of the work 3 is extracted, and the inspection is performed based on whether or not the distance between the position and the reference position is within a reference value. Various known methods such as a method of detecting the length and checking whether the length is within the standard can be employed. Finally, in step S8, the inspection result is monitored 17
Or output by printing with a printer.

Since the other side of the work 3 is photographed as a silhouette image, the surface irregularities in the upper surface of the work 3 are clearly and clearly raised as a silhouette contour in the silhouette image of the other side. In addition, the ridge on the upper surface of the work 3 is clearly captured in the reflection image.

Not only the contour of the upper surface of the work, but also the surface irregularities and ridges in the upper surface of the work can be clearly captured on one imaging screen. Items can be visually inspected, and inspection labor can be saved.

Although the present invention has been described with reference to the embodiment shown in the drawings, the present invention is not limited to this embodiment and can be variously modified. The image processing of the visual inspection may be performed not only based on the binarized image data but also using the captured multi-valued (eg, 8-bit) image data. Further, not only simultaneous capture of two images but also capture and division processing of two or more images are possible.

[0036]

As described above, according to the present invention, the main surface of the work is photographed as a reflection image by the first lighting device, but the other side of the work is silhouetted image by the third lighting device. Because the surface unevenness in the main surface of the work is raised as a silhouette contour in the silhouette image of the other side in a clear and dark and sharp manner, and the ridge line on the main surface of the work is strongly reflected by the illumination light by the second illumination device, This is clearly captured in the reflection image. Not only the contour of the main surface of the work, but also surface irregularities and ridges in the main surface of the work can be clearly captured on one image screen, so the amount of external elements on the main surface can be taken in abundantly and many inspection items can be performed at once. Can be inspected, and labor saving can be achieved.

Further, according to the present invention, the first image area including only the reflection image of the main surface and the second image area including only the silhouette image of the other side are provided.
After extracting and binarizing threshold values corresponding to the unique luminance distribution in each image region, the image region is binarized using the unique binarization threshold values. Therefore, it is possible to apply the optimum binarization processing to the reflection image and the image of the inverse relationship between the yin and yang, that is, the silhouette image, so that not only the contour of the main surface, but also the surface unevenness and the ridge portion in the main surface of the work. Etc. can be clearly identified,
More inspection items can be inspected accurately.

Particularly, since the high-luminance ridge portion is included in the reflection image of the main surface of the work by the second illumination device, the high-luminance region corresponding to the reflection image in the luminance distribution of the first image area. Is shifted to higher brightness and emphasized,
The base of the luminance distribution is clarified, the extraction of the first binarization threshold value becomes easy, and the binarization processing of the first image area becomes appropriate. In addition, the base of the luminance distribution of the second image region including the silhouette image is clear, so that the second binarization threshold can be easily extracted, and the binarization process of the second image region is appropriate.
Therefore, more fine appearance elements in the main surface of the work can be inspected more at once.

The present invention further comprises a work transfer means for transferring the work to the inspection position along the work transfer path, and discharging the work from the inspection position after the inspection, wherein the first, second and third illuminations are provided. Either of the devices is disposed in the work transport path, and includes an illumination device drive unit for moving forward and backward the illumination device disposed in the work transport path. When the illumination device is transported to the inspection position, the illumination device is retracted from the work transport path to allow the workpiece to pass, and the illumination device is moved forward after passing the workpiece. Even in a structure in which the illumination devices are arranged in the X, Y, and Z axis directions, interference between the loading / unloading of the work and the illumination devices can be prevented.

[Brief description of the drawings]

FIG. 1 is a front view schematically showing a main part of an embodiment of an appearance inspection apparatus according to the present invention.

FIG. 2 is a side view schematically showing a main part of an embodiment of the appearance inspection apparatus of the present invention.

FIG. 3 is a diagram showing an image captured by a camera.

FIG. 4 is a front view showing the entire embodiment of FIG. 1;

FIG. 5 is a side view showing the entire embodiment of FIG. 1;

FIG. 6 is a functional block diagram of an image processing unit.

FIG. 7 is a diagram illustrating an image captured by a camera and illustrating a method of dividing two images.

FIG. 8 is a diagram illustrating a histogram of luminance extracted by a luminance distribution extracting unit.

FIG. 9 is a flowchart of a procedure performed by the image processing means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Image processing means 2 ... Camera 2A ... Lens 3 ... Work 3b ... Lead wire 4 ... Ring illumination device (first illumination device) 5 ... Transmission illumination device (third illumination device) 6 ... Fiber illumination device (second illumination device) 7) Reflection mirror 8 ... Illumination source 9 ... Reflection mirror for transmitted illumination 10 ... Diffusion plate 11 ... Cylinder (illumination device drive means) 12 ... Work transport means 13 ... Work transport path 14 ... Drive means 15 ... Clamp 17 ... Monitor 18 ... Top image 18K ... Top image brightness distribution 19 ... Side image (mirror image) 19K ... Side image distribution 20 ... Base 21 ... Extended column 22 ... Cylinder support frame 23 ... Upper arm 24 ... Lower arm 25 ... Frame 26-28 ... Attachment 30 ... A / D conversion means 31 ... Memory 32 ... Area designation memory 33 ... Control means 34 ... Data transfer means 35 ... Luminance distribution extraction Output means 35a ... Memory 36 ... Binary level extracting means 36a ... Memory 37 ... Binary memory 37A ... First binary memory 37B ... Second binary memory 38 ... Binary processing means.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01B 11/00-11/30 B07C 5/10 G06F 15/62 G06F 15/64

Claims (2)

(57) [Claims] 1. A first illuminating device for illuminating a main surface of a work from an X-axis direction which is a substantially normal direction thereof, and a second illuminator for illuminating an end surface orthogonal to the main surface of the work from a Y-axis direction.
And a third lighting device that diffusely illuminates one side surface orthogonal to the main surface of the work from the Z-axis direction, and an opposite side of the main surface of the work and one side surface of the work via an optical system. Imaging means for simultaneously capturing the other side as a reflection image and a silhouette image separated on one imaging screen, a first image area including only the reflection image of the main surface on the imaging screen, and a silhouette image of the other side An image cutout unit that cuts out the image into a second image region including only the first image region, a first image region based on the pixel data in the first image region, and a first image region corresponding to the first image region. In addition to extracting the binarization threshold, a luminance distribution of the second image area is created based on the pixel data in the second image area, and a second binarization threshold corresponding to the second luminance distribution is extracted. Binarization threshold extracting means, and first binarization The pixel data in the first image area is binarized using the value to obtain a first binarized image, and the pixel data in the second image area is binarized using a second binarization threshold value. Binarization processing means for obtaining a binarized image of
An appearance determining device for determining the appearance of the main surface and the other side of the work based on the binarized image and the second binarized image. 2. The apparatus according to claim 1, further comprising a work transfer means for transferring the work to an inspection position along a work transfer path, and discharging the work from the inspection position after the inspection.
Either of the second and third lighting devices is disposed in the work transport path, and the lighting device includes lighting device driving means for moving the lighting device disposed in the work transport path forward and backward. When the work is conveyed to the inspection position, the driving unit retreats the illumination device from the work conveyance path, passes the work, and advances the illumination device after passing the work. .