JP2950536B2 - Colorimetric system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate inspection system for inspecting a plate-like body such as a building board, and more particularly, to a plate-coloring system for measuring the color of a building board or the like.

[0002]

2. Description of the Related Art Conventionally, in a final step of an inspection line or a production line, a running building board is imaged from directly above using a TV camera, and acquired image data is input to a personal computer for data processing. There has been proposed a "board inspection system" for inspecting the surface shape and the like of a building board. On the other hand, using a photoelectric colorimeter or a spectrocolorimeter, a colorimetric system that measures the color of an object to be measured and converts it to numerical values for evaluation
Has been developed and is being implemented in the field of color management of dyed articles, paint boards, and the like.

A colorimetry system strictly defines colorimetry conditions and accurately measures the color of an object under the conditions. This is based on the premise that measurement is performed on a single colored plane, and the measurement area is usually within a range where a circle having a diameter of about 25 mm can be measured even if it is large. further,
The measurement is performed with an integrating sphere or the like in a contact state so as to receive the total reflection light from the measurement object.

[0004]

Therefore, although an imaging system using a TV camera lacks accuracy in terms of color evaluation, it is highly applicable as a system incorporated in a line because it is non-contact. In contrast, conventional colorimetric systems that use photoelectric colorimeters or spectrophotometers, while guaranteeing accuracy in terms of color evaluation, are contact measurements and cannot be incorporated into lines. Have difficulty. In particular, it is extremely difficult to apply to a building board having an uneven surface shape. The present invention has been made in view of such circumstances, and an object of the present invention is to provide a plate-shaped colorimetric system that can be incorporated into a line.

[0005]

A colorimetric system according to the present invention is a colorimetric system for measuring the color of a plate-like object, comprising: a plurality of electronic cameras for imaging the plate-like object; Signal processing means for obtaining a color frequency distribution of pixels .

[0006]

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an overall side view of a colorimetric system according to the present embodiment. The plate-like body, for example, the building board 1 is conveyed on a conveyer arranged continuously. The carry-in conveyor 2
There is a first conveyor 4 in the measurement booth 3, a third conveyor 5 and an unloading conveyor 6 outside the measurement booth 3. The first conveyor 3 and the third conveyor 5
, A second conveyor 11 for the measuring unit 10 is provided, and a table lifter 7 for vertically moving the reference white plate 8 is provided below the measuring unit 10. On the table lifter 7, a white plate mounting table 9 on which a reference white plate 8 serving as a reference for color measurement rides is provided. The measurement booth 3 has an entrance shutter 3I and an exit shutter 3E to prevent light from entering the booth 3 from outside during measurement. The measurement booth 3 has an inner wall, a ceiling,
And the floor is painted black. The building board 1 to be measured is
From the loading standby position P1 to the measurement standby position P
2. It progresses to measurement points MP1, MP2, MP3, measurement completion position P3, and unloading completion position P4.

Next, the measuring section 10 will be described in detail with reference to FIG. A measuring box B whose lower surface is close to the measuring unit 10 where the building board 1 conveyed on the second conveyor 11 stops for color measurement, to such an extent that the running of the building board 1 is not hindered.
Is provided. Inside the upper surface BU of the measurement box B, for example, a D ₆₅ standard light source 21 which is a xenon lamp with a color temperature correction filter is incorporated, and illuminates the building board 1 from a direction perpendicular to the building board 1. . The measurement box B has a predetermined range covered, and the inner wall surface is painted black. CCD cameras 20A, 20B, and 2 for capturing still images are provided on four side surfaces BE of the measurement box B, respectively.
0C and 20D are provided. All of these CCD cameras 20A to 20D are arranged so as to be inclined at an angle of approximately 45 ° with the plane of the building board 1 to be measured.
The light receiving distances from the measurement points are equal. Also, to prevent light from leaking to the outside,
Only the distal ends of the CCD cameras 20A to 20D enter the measurement box B and receive the reflected light.

On the other hand, below the measurement box B, a reference white plate 8 having a white color as a color reference for color measurement is arranged. The reference white plate 8 includes CCD cameras 20A to 20A.
A plate slightly larger than the imaging area of D, which has a flat surface shape or the same surface shape as the building board 1, and which is made by, for example, painting and finishing MgO with a predetermined coating film is used. The reference white plate 8 is mounted on a white plate mounting table 9 and is moved up and down by a table lifter 7. This elevating operation is performed by, for example, the electric hydraulic cylinder 22.

Next, a time chart of the measurement will be described with reference to FIG. First, the entrance shutter 3I and the exit shutter 3E of the measurement booth 3 are opened, and all of the five conveyors 2, 4, 5, 6, and 11 are operated at the same speed. The reference plate 1 is transported from the carry-in standby position P1 to the measurement standby position P2. At this time, the carry-in conveyor 2 and the first conveyor 4 contribute to the conveyance of the reference plate 1. In the steady operation state,
At the same time, the building board 1 for which the color measurement has already been completed is carried out of the measurement booth 3 from the measurement completion position P3 to the carry-out completion position P4 by the third conveyor 5 and the carry-out conveyor 6. The reference plate 1 enters the measurement booth 3 and the measurement standby position P2
, Five conveyors 2, 4, 5, 6, 1
1 is stopped, and the entrance shutter 3I and the exit shutter 3E are closed. When the shutters 3I and 3E are closed, the inside of the measurement booth 3 is shielded from the outside to form a dark room. In order to measure each of the front part, the central part and the rear part of the reference plate 1, the first transport conveyor 4, the second transport conveyor 11 and the third transport conveyor 5 are intermittently operated at the same speed and intermittently. During this time, the reference plate 1 has the measurement point MP
Stop at each position in the order of 1, MP2, MP3, and measurement (1), (2), (3) is performed at each position. That is, CCD
The comparison reference image data from four directions corresponding to the cameras 20A to 20D is obtained. When the imaging at each position is completed, the reference plate 1 reaches the measurement completion position P3, and the entrance shutter 3
The reference plate 1 is conveyed to the unloading completion position P4 by operating the five conveyors 2, 4, 5, 6, and 11 at the same speed by opening the shutter I and the exit shutter 3E. In this case, the third conveyor 5 and the unloading conveyor 6 contribute to the conveyance of the reference plate 1.
As described above, at this time, the inspection board 1, which is a building board to be measured next, is carried into the measurement booth 3 from the carry-in standby position P1 to the measurement standby position P2.

Next, the process shifts to the measurement of the test plate 1, and the test plate 1 is moved to the measurement points MP1 and MP1 according to the same time chart.
By transporting the test plate 1 to MP2 and MP3, the front, center, and rear portions of the inspection plate 1 are imaged. FIG. 4 is a block diagram showing the basic configuration of the present invention. CCD camera 2
The image signals captured in 0A to 20D are sent to the main controller 30. The main controller 30 includes a timer 30A and each of the CCD cameras 20A to 20A.
The image signal captured in 0D is processed and the data is stored in the image memory 31. A keyboard 32 for inputting necessary data and a display 33 for displaying necessary data are connected to the main controller 30. The transport conveyors 2, 4, 5, 6, 11, the entrance and exit shutters 3I and 3E, and the table lifter 7 are respectively provided with a transport conveyor controller 34 and a shutter controller 3 connected to the main controller 30.
5 and the table lifter controller 36. Further, the main controller 30 is connected to a standard light source controller 37 that detects a change in the spectral energy distribution of the standard light source 21, performs a correction calculation, and uses it for color evaluation.

FIG. 5 is a diagram showing a configuration of recording data in the image memory 31 shown in FIG. CCD camera 20
The calibration data from A is R component, G component,
It is stored in the area 51 for each B component. This data area has a storage capacity of, for example, 500 pixels × 800 pixels. Next, the sampling data from the CCD camera 20A is stored in the areas 52, 53, and 54 for the front, center, and rear portions of the reference plate 1 for each of the R, G, and B components. Further, the sampling data of the inspection plate 1 is R component, G
The front part, the center part, and the rear part are stored in the areas 55, 56, and 57 for each component and B component. This CCD camera 2
CCD camera 20B, 20A as well as 0A data storage.
The measurement results for C and 20D are stored in the corresponding areas. The measurement data stored in the data area 51 is updated for each calibration, and the data area 5 is updated.
The measurement data stored in 2 to 54 is updated each time the type of the test plate 1 is changed and the measurement of the reference plate 1 is performed. The measurement data stored in the data areas 55 to 57 is It is updated for every measurement.

FIG. 6 shows the main controller 3 shown in FIG.
7 is a flowchart illustrating a control operation of a zero. First, it is determined whether or not the system power is ON (step S1). If NO, the process waits until the system power is turned ON. If YES, initial settings such as data including settings for receiving measurement data from the CCD cameras 20A to 20D are performed (step S2).

In step S3, the CCD camera 20
A to 20D calibration is performed. That is, the entrance shutter 3I and the exit shutter 3 of the measurement booth 3
E is closed, the reference white plate 8 is raised by the table lifter 7, and the intermediate position between the crest and the valley bottom in the thickness direction thereof (determined in advance from the design value) is determined based on the transport back surface position of the reference plate 1. With the white plate 8 positioned, the CCD camera 20A
20D, an image of the reference white plate 8 is taken, a white reference level in each direction is measured, sampling data from the CCD cameras 20A to 20D is received, and the data is sequentially transferred and recorded in the image memory 31. When this measurement is completed, the reference white plate 8 is lowered.

This calibration is performed before the start of the measurement. After that, since the characteristics of the CCD cameras 20A to 20D may change depending on the temperature, the calibration is frequently performed at the beginning of the measurement when the temperature rises. It is good to do it and to do it gradually. Also, as shown in FIG. 6, in the colorimetric procedure, the timing at which the type of the inspection plate 1 is changed is appropriate, but it is not always necessary to perform this at this timing and may be performed at other times. .

In step S4, the colorimetry of the reference plate 1 (described in detail in FIG. 7) is performed. In step S5, the colorimetry of the inspection plate 1 is performed. In step S6, data processing for color evaluation (described in detail in FIG. 8) is performed. Then, in step S7, the color evaluation result is displayed on the display 33. In step S8,
It is determined whether or not the colorimetry of the same type of inspection plate 1 has been completed, and if the colorimetry of the same type of inspection plate 1 is still continued, the process returns to step S5 and the colorimetry of the next inspection plate 1 is performed. If the color measurement of the type of the inspection plate 1 is completed with YES,
Proceeding to step S9, it is determined whether or not to terminate the measurement itself. If the determination is NO, the color of the next type of test plate 1 is measured, the process returns to step S3, and if the measurement is terminated, the determination is YES. After finishing the measurement (step S10),
End the flow. In these controls, control data is exchanged between the main controller 30 and the controllers 34, 35, 36, and 37, and color measurement timing control is performed according to the time chart described with reference to FIG.

FIG. 7 shows the “color measurement (S
4) is a flowchart showing the content of "4)." First, in step S100, the reference plate 1 is moved to the measurement standby position P
It is determined whether or not 2 has been reached. If NO, the control waits until the reference plate 1 reaches the measurement standby position P2.
If YES, the entrance shutter 3 in step S101.
I and the exit shutter 3E are closed. Next, the reference plate 1
It is determined whether has reached the measurement point MP1 (step S102). If NO, the control waits until the reference plate 1 reaches the measurement point MP1. If YES, the process proceeds to step S103, where each of the CCD cameras 20A-
The measurement (1) of the front part of the reference plate 1 is performed by 20D. Next, in step S104, the CCD cameras 20A-2A
The sampling data from 0D is received and the image memory 31
Record the reception.

Next, it is determined whether the reference plate 1 has reached the measurement point MP2 (step S105). N
If it is O, it waits until the reference plate 1 reaches the measurement point MP2. If YES, the process proceeds to step S106, and the measurement (2) of the central portion of the reference plate 1 is performed by each of the CCD cameras 20A to 20D. Next, in step S107, the sampling data from the CCD cameras 20A to 20D is received and received and recorded in the image memory 31. Next, it is determined whether the reference plate 1 has reached the measurement point MP3 (step S108). If NO, the control waits until the reference plate 1 reaches the measurement point MP3. YE
If S, the process proceeds to step S109, and measurement (3) of the rear part of the reference plate 1 is performed by each of the CCD cameras 20A to 20D. Next, in step S110, the CCD camera 2
The sampling data from 0A to 20D is received and received and recorded in the image memory 31.

Next, in step S111, it is determined whether the reference plate 1 has reached the measurement completion position P3. If NO, the control waits until the reference plate 1 reaches the measurement completion position P3. If YES, the entrance shutter 3I and the exit shutter 3E are opened in step S112,
The reference plate 1 is carried out of the measurement booth 3, and the "color measurement of the reference plate 1 (S4)" ends. The “colorimetry of the inspection plate 1 (S5)” shown in FIG. 6 may be controlled according to the same flow as the “colorimetry of the reference plate 1 (S4)”.

FIG. 8 is a flow chart showing the contents of the "data processing for color evaluation (S6)" shown in FIG.
First, in step S200, the CCD camera 20A
The respective white level references are determined from the calibration data for every 20D. At this time, the correction calculation value obtained based on the fluctuation of the spectral energy distribution of the standard light source 21 detected by the standard light source controller 37 is added.
Next, in step S201, the CCD camera 20
A first measurement window in one screen captured by A to 20D is set. This measurement window is for setting the position and size of the measurement range. In step S202, a frequency distribution is obtained for each of the R, G, and B data of all pixels in the measurement window for the reference plate 1 for each of the CCD cameras 20A to 20D. This gives R,
The distribution in the measurement window is checked for each of the components G and B. At this time, R, G, and B components use relative values of R, G, and B of each pixel with respect to the white level reference obtained by the calibration in step S200. This result is recorded in step S203 (reference plate 1).
Is assumed to be A). In step S204,
A frequency distribution is obtained for each of the R, G, and B data of all the pixels in the measurement window for the inspection plate 1 for each of the CCD cameras 20A to 20D in the same manner as in step S202.
In step S205, this result is recorded (the frequency distribution of the inspection plate 1 is B).

Next, in step S206, the measurement window is changed. The measurement windows are sequentially changed by setting a predetermined function. In step S207, frequency distributions (A) and (B) are obtained for each of the R, G, and B data for each of the reference plate 1 and the inspection plate 1 for each of the CCD cameras 20A to 20D within the changed measurement window. . In step S208, it is determined whether to change to the next measurement window. YES
If NO, the process returns to step S206. If NO, the process proceeds to step S209. For each measurement window, R, G, and R are determined based on the frequency distribution (A) of the reference plate 1 and the frequency distribution (B) of the inspection plate 1. The color distribution evaluation for each B is performed. For example, frequency distribution
(A) is compared with the frequency distribution (B). If both are dispersed in the same way, the product is acceptable, but if there is a difference in the distribution and the difference is larger than a predetermined value, the product is passed. It will be determined that there is a defect.

Further, an average of each of the R, G, and B data of all the pixels in the imaging screens of the CCD cameras 20A to 20D is calculated to determine one comprehensive colorimetric data unique to each inspection plate 1. Finally, in step S210, the evaluation result and the comprehensive colorimetric data obtained in step S209 are processed into display data, and “data processing for color evaluation (S
6). As described above, the preferred embodiments of the present invention have been described. However, the present invention is not limited to these embodiments, and various improvements and design changes can be made without departing from the gist of the present invention. It is.

For example, an electronic camera such as a CCD camera may capture moving images, and the number and position of the electronic cameras may be changed according to the properties and characteristics of the plate. When the plate is a building board, the pattern is often horizontal, so in this case, at least two electronic cameras can be arranged in front of and behind the building board to capture images from above and below the pattern. desirable.

Further, the measurement positions of the plate-like body are the front part, the center part and the rear part, but the measurement positions can be appropriately changed depending on the surface shape and size. further,
Instead of obtaining the frequency distribution of each of the R, G, and B components, the frequency distribution of a set of R, G, and B components may be obtained. Also, one piece of data unique to each test board 1 is determined as comprehensive colorimetric data. However, in the case of the test board 1 coated with a plurality of paints of different colors, the color distribution is concentrated. May be determined. Further, in this specification, color measurement means not only measurement of hue but also measurement of lightness. For this reason, it is assumed that the color signals from the electronic camera include those capable of recognizing brightness.

[0025]

As described above, according to the present invention, the color frequency distribution of pixels from a plurality of electronic cameras is obtained, thereby eliminating the bias inherent in each camera and more reliably measuring the color of the plate-like body. An assessment can be made. Moreover, in the case where the plate-shaped object to be measured is long or has an uneven surface shape, it is particularly effective to apply the present invention, and from a multilateral viewpoint without stopping the production line. Comprehensive colorimetric evaluation can be performed.

[Brief description of the drawings]

FIG. 1 is an overall side view of an embodiment of the present invention.

FIG. 2 is a perspective view of a measuring unit according to the present invention.

FIG. 3 is a time chart showing the operation of each unit of the present invention.

FIG. 4 is a block diagram of a basic configuration of the present invention.

FIG. 5 is a diagram showing a recording data configuration in an image memory of the present invention.

FIG. 6 is a flowchart showing a control operation of the main controller of the present invention.

FIG. 7 is a flowchart of color measurement control according to the present invention.

FIG. 8 is a flowchart of data processing for color evaluation according to the present invention.

[Explanation of symbols]

B Measurement box 1 Building board (reference board, inspection board) 2 Loading conveyor 3 Measurement booth 3I Inlet shutter 3E Exit shutter 4 First transport conveyor 5 Third transport conveyor 6 Unloading conveyor 7 Table lifter 8 Reference white board 9 White board mounting Table 10 Measurement unit 11 Second transport conveyor 20A, 20B, 20C, 20D CCD camera 21 Standard light source 22 Electric hydraulic cylinder 30 Main controller 31 Image memory 32 Keyboard 33 Display 34 Transport conveyor controller 35 Shutter controller 36 Table lifter controller 51 , 52, 53, 54, 55, 56, 57 Sampling data storage area

Claims (1)

(57) [Claims] In a colorimetric system for measuring the color of a plate, a plurality of electronic cameras for imaging the plate and signal processing means for obtaining a color frequency distribution of pixels from the plurality of electronic cameras are provided. A colorimetric system comprising: