JP2581133B2 - Automatic inspection system for coating smoothness - Google Patents

Description

Description: Object of the Invention [Industrial application field] The present invention relates to a coating film smoothness automatic inspection device for detecting a coating film smoothness.

[Prior Art] Conventionally, various inventions and proposals have been made for automatically detecting the smoothness (yuzu skin degree) of a coating film. As the invention and the proposal, for example, a "method for measuring the smoothness of a coated surface" disclosed in JP-A-63-18210 can be mentioned.

In the above proposal, as shown in FIG.
A vertical stripe pattern is projected onto the painted surface 52 by the 50 and the vertical stripe lattice 51, the projected vertical stripe pattern is imaged by the CCD camera 53, and the microcomputer 54 as an image processing device converts a video signal to be imaged and output to a predetermined value. The variation of the interval between the vertical stripes is calculated from the binary video signal obtained by comparison with the reference value to determine the degree of yuzu skin (painted surface smoothness). Here, urethane 55 in the figure is a light-blocking elastic body for preventing external light from entering the inside of the device.

[Problems to be Solved by the Invention] However, the above-mentioned conventional automatic inspection apparatus for coating film smoothness uses a video signal to be imaged and output as it is in the form of 2
Because it is a configuration that changes the value, it is easily affected by external light and paint color. For this reason, the inspection device must be
The external light had to be blocked by a light-blocking elastic body or the like. For this reason, the following problems were considered. (A) Generally, the mounting position of the product as an inspection object on the conveyor, which is assembled, painted or processed on a conveyor, that is, is not fixed at a fixed position,
Causes position fluctuations. For example, in an automobile manufacturing line, the positional accuracy of the vehicle body with respect to the line (conveyor) is about ± 15 [mm], and the mounting position and the positional accuracy vary depending on the vehicle type. Therefore, in the conventional inspection device,
The problem that it is not possible to inspect the coating film of the product on the production line because it is necessary to make accurate contact.
Although there is no problem in inspecting the paint film that has been baked and finished, it is necessary to inspect the test object that has a normal paint film, especially a paint film that has not been completely dried, because it may damage the paint film. The problem of being unable to do so was considered.

SUMMARY OF THE INVENTION The automatic coating film smoothness inspection apparatus of the present invention has been made to solve the above problems and to easily perform an inspection of a coating film of a product on a production line.

DETAILED DESCRIPTION OF THE INVENTION [Means for Solving the Problems] An automatic coating film smoothness inspection apparatus of the present invention identifies the type of a painted object to be inspected on a conveyor as exemplified in FIG. Type discrimination means (M1), light and dark pattern projection means (M2) for irradiating the object with a predetermined light and dark stripe pattern, and the light and dark pattern projection means (M2) are projected onto the surface of the object to be inspected. An image pickup means (M3) for picking up an image of a light and dark stripe pattern as a light intensity level signal; and a predetermined predetermined image pickup means (M3) according to the type of the inspection object identified by the type identification means (M1). A moving means (M4) for moving to a position; and an image obtained by comparing the intensity level signal of the light output by the imaging means (M3) moved by the moving means (M4) with a predetermined reference value. The light and dark stripe pattern is reproduced as a binary signal. The thinning processing means (M) for thinning the bright or dark portions of the light and dark stripes of the binary signal to a predetermined line width.
5) dividing the thinned light and dark stripe pattern into blocks of four pixels adjacent to each other on the screen, classifying the blocks based on the arrangement of light and dark in the blocks, and performing a predetermined arithmetic processing. And a smoothness judging means (M6) for judging the smoothness of the coating film of the inspection object based on the calculation result.

[Function] The coating film smoothness automatic inspection apparatus of the present invention having the above-described configuration is arranged such that the imaging means (M3) moves the moving means (M4) in accordance with the type of the inspection object on the conveyor identified by the type identifying means (M1).
Is moved to a predetermined position, and the moved image pickup means (M3) is used to project light and dark pattern projection means (M2).
The light and dark fringe pattern on the surface of the test object irradiated with the light is imaged as a light intensity level signal, and the thinning processing means (M5) compares the light intensity level signal with a predetermined reference value to thereby obtain an image. The stripe pattern is changed to a light and dark stripe pattern of a binary signal, and a process of thinning a bright portion or a dark portion of the light and dark stripe pattern of the binary signal to a predetermined line width is performed. Thereafter, the smoothness determining means (M6) divides the thinned light and dark stripe pattern into blocks of four pixels adjacent to each other on the screen and classifies the blocks based on the arrangement of light and dark in the blocks. A predetermined calculation process is performed, and the smoothness of the coating film of the inspection object is determined based on the calculation result. This classification can be exemplified, for example, such that the direction of the thinned line is vertical (two pixels vertically connected are dark), left downward (dark is lower left and upper right), right lower (dark is upper left and lower right), and the like.
These may be given numerical codes. If the direction of the line in the block is vertical, the stripe pattern can be regarded as undisturbed (normal), and if the direction of the line is oblique, the stripe pattern can be regarded as disturbed (abnormal). . Therefore, for example, if the ratio of the number of normal blocks to the number of abnormal blocks is calculated as the arithmetic processing, the smoothness of the coating film can be determined from the ratio. Further, for example, when a code is assigned to each block according to the direction of the line, a variation (standard deviation) of the code is obtained by arithmetic processing, and the smoothness can be determined from the variation.

In general, as the smoothness of a coating film deteriorates, the light and dark fringe pattern applied to the portion is distorted. The automatic coating film smoothness inspection apparatus of the present invention focuses on this phenomenon, and picks up an image of a light and dark stripe pattern on the surface of the inspection object, that is, inspects the inspection object without directly contacting the inspection object. It works to determine the smoothness of the inspection object. In addition, since the imaging means (M3) is moved according to the type of the object to be inspected on the conveyor, it is possible to accurately irradiate the light and dark stripe pattern irrespective of the difference in the mounting position of the object to be inspected.

Example Next, a preferred example for further clarifying the configuration of the coating film smoothness automatic inspection apparatus of the present invention will be described with reference to the drawings.

As shown in FIG. 2, the automatic coating film smoothness inspection apparatus of the present embodiment includes a recognition sensor 3 that reads a serial number of a vehicle body 2 placed on a line conveyor 1 and having completed a painting operation,
A stripe pattern projection device 4 for irradiating the vehicle body 2 with a light and dark stripe pattern, an image pickup tube (hereinafter referred to as a TV camera) 6 for imaging a virtual image of the light and dark stripe pattern projected on the vehicle body 2 via a mirror 5, and a recognition sensor A personal computer (hereinafter, may be simply referred to as a personal computer) 7 for determining the vehicle type and the paint color of the vehicle body 2 according to a signal output from the vehicle 3 and a paint signal for the vehicle body 2 based on an image signal (video signal) output from the TV camera 6. It comprises an image processing device 8 for performing a film inspection, a robot control panel 10 for driving and controlling the position of a portal robot 9 to which a stripe pattern projection device 4 and a TV camera 6 are attached.

The recognition sensor 3 reads the serial number assigned to the vehicle body 2 from the pattern recognition, and is configured to output a signal corresponding to the read serial number to the personal computer 7.

As shown in FIG. 3, the stripe pattern projection device 4 is composed of a flat plate 4a having a large number of equally spaced slits and a light emitting light source 4c for emitting scattered light through a diffusion plate 4b. A stripe pattern having a predetermined pitch (in this embodiment, the interval between the bright and dark portions is set to 1.5 mm) is projected on the surface of the vehicle body 2 as an object.

The TV camera 6 includes a mirror 5 fixed to a mirror holder 5a.
A virtual image of a striped pattern projected on the surface of the vehicle body 2 is captured through the interface, and a video signal corresponding to the intensity of the striped pattern is output. The TV camera 6 is provided with a diaphragm 6a so that the input light amount can be adjusted.

The above-mentioned striped pattern projection device 4, TV camera 6, and mirror holder 5a are fixed to a jib 9b of a portal robot 9 by a frame 9a. As is well known, the portal robot 9 is configured to be driven and controlled by a robot control panel 10 to move the frame 9a back and forth, left and right, and up and down.

As shown in FIG. 4, the personal computer 7 is configured as a logical operation circuit having a well-known CPU 7a, ROM 7b, and RAM 7c as a center, and these and an external input / output circuit 7d interconnected by a bus 7e. Similarly, the image processing device 8 mainly includes a CPU 8a, a ROM 8b, and a RAM 8c, and A / D
The converter 8d, the D / A converter 8e, and the external input / output circuit 8f are connected to a bus 8g.
As logic operation circuits connected to each other.

The external input / output circuit 7d of the personal computer 7 includes:
The recognition sensor 3 is connected, and a CRT display device (not shown) arranged at the site of a painting process for painting the vehicle body 2 on the conveyor 1 is also connected.

The robot control panel 10 and the CRT display device 8h are connected to the external input / output circuit 8f of the image processing device 8, and the external input / output circuit 7d of the personal computer 7 is bidirectionally connected so as to be able to input and output. . Also, A / D converter 8
The TV camera 6 is connected to d to input the video signal to be output, and the aperture unit 6a of the TV camera 6 is connected to the D / A converter 8e.
Is connected.

In this embodiment, the recognition sensor 3 and the personal computer 7 serve as the type identifying means,
Corresponds to the light and dark stripe pattern projection means, the mirror 5 and the TV camera 6 correspond to the imaging means, the robot 9 and the robot control panel 10 correspond to the moving means, and the image processing device 8 corresponds to the thinning processing means and the smoothness judgment means, respectively. .

The operation of this embodiment having the above configuration will be described with reference to the flowcharts shown in FIGS. Here, the "PC main routine" shown in FIG. 5 shows the processing executed by the personal computer 7, and the "image processing main routine" shown in FIG. 6 and the "smoothness determination processing routine" shown in FIG. The processing executed by the image processing device 8 is shown.

The painted body 2 is conveyed at a constant speed by the conveyor 1, but when it reaches a predetermined position, the serial number is read by the recognition sensor 3. PC 7
The CPU 7a inputs the serial number read by the recognition sensor 3 via the external input / output circuit 7d (step 100), and subsequently, from the serial number, the type of the vehicle body 2, the color of the applied paint, and the original coating film. A process for searching the ROM 7b for the smoothness or the like that should be possessed is performed (step 110).

When the vehicle type and color information of the vehicle body 2 are obtained, this information is output to the image processing device 8 via the external input / output circuit 7d (step 120). Thereafter, the process enters a state of waiting for input from the image processing device 8 (step 130).

On the other hand, when the information of the vehicle body 2 is input from the personal computer 7 (step 140), the CPU 8a of the image processing device 8 performs a process of outputting position data predetermined for each vehicle type to the robot control panel 10 based on the information (step 140). Step 150). Thereby, each motor (not shown) of the portal robot 9 is driven and controlled by the robot control panel 10, and moves the TV camera 6 to a predetermined position for each vehicle type. When the TV camera 6 is moved to a predetermined position, the control of the aperture section 6a of the TV camera 6 is tried (step 160). This process is performed as follows.

First, the CPU 8a opens the aperture 6a by a predetermined opening based on the color information of the vehicle body 2 input from the personal computer 7, and inputs a virtual image of a striped pattern on the vehicle body 2 via the mirror 5 as a light intensity level signal. The video signal VD1 as the light level signal is converted into a digital value by the A / D converter 8d, and is taken into the RAM 8c as an image memory. The CPU 8a compares the maximum value or the minimum value with the respective reference values so that the level of the video signal VD1 converted into the digital value becomes a value within a predetermined range, and the diaphragm unit via the D / A converter 8e. Control 6a and adjust its opening. Thereby, the value of the video signal VD1 captured by the TV camera 6 and taken into the RAM 8c is a digital value within a predetermined range. Here, the video signal VD1 shown in FIG. 8 indicates the video signal after the aperture control has been performed.

In general, when the smoothness of the coating film is good, the virtual image of the striped pattern projected on the surface of the vehicle body 2 is such that a bright portion and a dark portion are regularly arranged at a predetermined pitch, as shown in FIG. 9A. It becomes a lined image. On the other hand, when the smoothness of the coating film is poor, the stripe pattern is distorted as the smoothness becomes poor, resulting in an irregular image as shown in FIG. 9B. When this irregular stripe pattern is imaged as a light intensity level signal, a distorted portion (hereinafter, referred to as an irregular portion) bd can be regarded as a portion where the interval between the peaks of the level signal varies. (FIG. 8 video signal VD1 irregular portion bd). In addition, TV
The video signal VD1 from the camera 6 is a video signal obtained by scan scanning orthogonal to the stripe pattern. Therefore, the timing chart shown in FIG. 8 uses time t as a parameter. A signal on the minus side of the video signal VD1 indicates a synchronization signal. Therefore, the video signal VD1 shown in FIG. 8 represents one horizontal scanning line. The screens shown in FIGS. 9A and 9B reproduce the video signal VD1 on the display device CRT.

When the aperture control is performed (step 160), a smoothness determination process for determining the smoothness of the coating film of the vehicle body 2 from the captured video signal VD1 is performed (step 170). This smoothness determination processing is performed as follows.

First, processing for differentiating the captured video signal VD1 is performed (step 171 in FIG. 7). Since the video signal VD1 is a signal obtained by scan scanning orthogonal to the stripe pattern, this processing is to differentiate the reproduced image in the X direction. By differentiating the video signal VD1, a signal is obtained in which the rising from the dark part to the bright part is plus, the falling from the bright part to the dark part is minus, and both the bright and dark parts are at zero level (FIG. 8 video signal VD2). When the differentiated video signal VD2 is obtained, the video signal VD2 is subsequently converted into an absolute value (step 172, FIG. 8 video signal VD3), and the levels of the absolutely converted video signal VD3 are averaged and compared. Calculate the reference value V1 (step 17)
3). Thereafter, a process of comparing the calculated comparison reference value V1 with the absolute value of the video signal VD3 and binarizing the video signal VD3 is performed (step 174, video signal VD4 in FIG. 8). The video signal VD4 reproduced on the screen is shown in FIG.
[D]. Here, the reproduction screen shown in FIG. 9 [C] is a case where the smoothness is good, and the reproduction screen shown in FIG. 9 [D] is a case where the smoothness is bad.

When the binarized video signal VD4 is obtained, a thinning process is performed next (step 175). This process is a process in which, of the dark portions of the bright and dark striped pattern reproduced on the screen, only the pixels of the dark portions displayed first by scan scanning are left and the other portions are bright portions (FIG. 8 video signal VD5). ). Therefore,
As shown in FIG. 9 [E] or [F], the bright and dark striped pattern reproduced on the screen is a striped pattern in which only the pixels in the bright portion are vertically connected. Here, the reproduction screen shown in FIG. 9 [E] is a case where the smoothness is good, and the reproduction screen shown in FIG. 9 [F] is a case where the smoothness is bad.

When the thinning process is performed, a process of determining the direction of the thinned line and coding the line direction is performed (step 176). This processing is performed according to the pattern shown in FIG. That is, the pixels on the screen are divided into blocks of adjacent four pixels, and a code is attached to each block according to the line direction (pattern) of this block. In this embodiment, a value of 50 is assigned as a code when the line direction of the block is downward-leftward, a value of 100 when the line direction is vertical, and a value of 150 when the line direction is downward-rightward. Note that blocks other than the line direction shown in FIG. 10 are assigned a value of zero. After the coding, the smoothness OP of the coating film is determined (calculated) according to the following equation.

OP = P1 / P2 Here, P1 is the number of normal blocks whose line direction is vertical, and P2 is the number of blocks whose line direction is lower left or lower right.

Therefore, the larger the value of the determined smoothness (hereinafter, also referred to as the determined smoothness) OP, the better the smoothness, and the smoothness OP
Is smaller, the smoothness becomes worse. Where the eleventh
The graph shown in the figure shows the judgment smoothness OP according to the present example of nine coating film standard plates in which sensory evaluation of the degree of yuzu skin was performed. From this graph, it can be seen that the smaller the smoothness OP is, the worse the sensory smoothness is, and furthermore, it has a predetermined relationship.

The above-described determination smoothness OP is, as shown in FIG.
Each of the parts (points P1 to P14) of the vehicle body 2 is obtained, and the determination smoothness OP is ranked. The obtained smoothness information is stored in an external input / output circuit.
8f to the personal computer 7 (FIG. 6, step 18).
0). Thereafter, the process returns to step 140 described above. still,
When determining the judgment smoothness OP of each inspection position (points P1 to P14) of the vehicle body 2, the TV camera 6
Are moved to predetermined positions.

When the CPU 7a of the personal computer 7 inputs the smoothness information such as the judgment smoothness OP via the external input / output circuit 7d (step 130 in FIG. 5), the CPU 7a converts the information into the inspection date, vehicle type, paint color and serial number. Is output to the painting process via the external input / output circuit 7d together with the information of step (d) (step 190). Thereafter, the processing returns to step 100 described above.

According to the coating film smoothness automatic inspection apparatus of the present embodiment described in detail above, the coating film smoothness of the vehicle body 2 having poor position accuracy on the conveyor 1 moving at a predetermined speed is automatically and damaged. It has an excellent effect that the inspection can be performed without any trouble. Further, since the position of the TV camera 6 is moved and the input light amount of the TV camera 6 is adjusted according to the type of the vehicle body 2 and the paint color of the object to be inspected, an excellent effect that inspection reliability and versatility are high. To play. Furthermore, as a result, it is possible to further improve the reliability of the coating by adjusting various conditions of the coating in the coating process, for example, the pressure of the compressor and the content of the thinner, and to further stabilize the uniformity of the coating film. It has an excellent effect that it can be Further, in the present embodiment, since the smoothness of the coating film is determined from the direction of the thinned striped pattern, there is an effect that it can be easily configured using a generally used image processing apparatus. I have.

The coating film smoothness automatic inspection apparatus of the present invention is not limited to the above-described embodiment at all, and can be implemented in various modes without departing from the gist of the present invention. For example, in this embodiment, the smoothness OP is determined based on the ratio between the number of normal blocks and the number of abnormal blocks in the line direction. ), And the smoothness OP may be determined from the variation. Also, since the personal computer 7 has the smoothness that the vehicle body 2 should originally have, the personal computer 7 may be configured to compare this smoothness with the determination smoothness OP and output the comparison result.

According to the coating film smoothness automatic inspection apparatus of the present invention, an excellent effect that the coating film smoothness of a comparative inspection object on a production line can be inspected automatically and without damaging the coating film. Have. Further, since the imaging means is moved to a predetermined position in accordance with the type of the object to be inspected, an excellent effect that inspection reliability and versatility are high is achieved.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a basic configuration of an automatic coating film smoothness inspection apparatus of the present invention, FIG. 2 is an overall schematic diagram showing an automatic coating film smoothness inspection apparatus of one embodiment of the present invention, and FIG. Is a partial view showing a stripe pattern projection device 4, an image pickup tube (TV camera) 6, etc.
FIG. 4 shows a personal computer 7 and an image processing device 8
FIG. 5 is a flowchart showing processing of a "PC main routine", FIG. 6 is a flowchart showing processing of an "image processing main routine", and FIG. 7 is a flowchart of a "smoothness determination processing routine". FIG. 8 is a flowchart showing the processing, FIG. 8 is a timing chart showing a video signal in each processing of the image processing apparatus 8, and FIG.
[B], [C], [D], [E], and [F] are explanatory diagrams showing images reproduced in the respective processes performed by the image processing device 8, and FIG. 10 is a diagram showing pixel line directions and codes thereof. FIG. 11 is a graph showing the relationship between the sensory citron texture and the determination smoothness OP, FIG. 12 is an explanatory diagram illustrating an inspection position of the smoothness of the vehicle body 2, and FIG. 1 is a schematic view showing an example of a coating film smoothness automatic inspection device of FIG. M1 ... Type identification means M2 ... Light / dark pattern projection means M3 ... Imaging means M4 ... Movement means M5 ... Thinning processing means M6 ... Smoothness determination means 1 ... Conveyer 2 ... Vehicle body 3 ... Recognition sensor 4. Stripe pattern projection device 6. Image pickup tube (TV camera) 7. Personal computer 8. Image processing device 9. Portal robot 10. Robot control panel

 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-61-204509 (JP, A) JP-A-61-249251 (JP, A) JP-A-63-18210 (JP, A)

Claims (1)

(57) [Claims] 1. A type identifying means for identifying the type of a painted object to be inspected on a conveyor, a light and dark stripe pattern projecting means for irradiating a predetermined light and dark stripe pattern to the inspected object, and the light and dark stripe pattern An imaging unit that captures an image of a bright and dark striped pattern projected on the surface of the inspection object by a projection unit as a light intensity level signal; and the imaging unit is predetermined according to a type of the inspection object identified by the type identification unit. Moving means for moving the image to a predetermined position, and comparing the intensity level signal of the light output by the imaging means moved by the moving means with a predetermined reference value to convert a light and dark stripe pattern imaged into a binary value. A thinning means for thinning the bright or dark portions of the light and dark stripes of the binary signal to a predetermined line width; and forming the thinned light and dark stripes adjacent to each other on the screen. Pixel block After dividing the block into units and classifying the block based on the arrangement of light and shade in the block, a predetermined calculation process is performed, and the smoothness of the coating film of the inspection object is determined based on the calculation result. And a means for automatically inspecting the smoothness of a coating film.