JPH0933349A - Color difference inspecting device for sheet material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color difference inspecting device in which the inspection data is graphed and whether the value of color difference is within an allowable range or not can be judged in real time. SOLUTION: This device is formed out of a first CPU 1 for controlling a carrying means 5 for a sheet material 15, an input part 5 of inspecting condition, a first display part 2 of inspecting condition, and a first output part 3 for outputting an initial condition, three color sensors 10, and a second CPU 7 for controlling the sensors 10 and also controlling a second display part 8 for displaying the detection result and a second output part 9 for outputting the detection result. The first CPU 1 and the second CPU 7 are mutually communicatable. In the second CPU 7, the color measurement data obtained by the sensors 10 is processed to determine the color difference value ΔE and brightness deviation value ΔL* with a standard color value, which are then graphed to judge whether these values are within a preset allowable range or not, and the result is displayed on the second display part 8 in real time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for inspecting a color difference of a sheet-like material, and more specifically, it uses a color sensor to inspect the color difference of a sheet-like material such as a woven fabric, a knit, a non-woven fabric or a film. Related to the device.

[0002]

2. Description of the Related Art Generally, in the process of dyeing industrial products such as cloths, films and plates, for example, woolen fabrics or cotton fabrics, color unevenness occurs due to uneven distribution of dyes, or partial coloring due to overheating or contamination with foreign matter occurs. Or stains that turn brown due to oil or the like.

Since such color unevenness, stains, etc. occur locally and suddenly, and are regarded as fatal defects in the appearance of industrial products, the inspector always visually inspects all products and all the products. The current situation is that they are inspecting.

Therefore, the labor required for the inspection is large, and in order to rationalize the labor, the following inspection methods have been conventionally known.

(1) A laser beam is scanned at a high speed in a direction perpendicular to a product (object to be inspected) conveyance direction,
Focusing on the point that the reflectance of the abnormal part changes with respect to the normal part, a method of detecting scratches, etc., (2) Scanning the surface of the product with a TV camera using an image sensor and extracting the image signal (3) A photoelectric colorimeter (color sensor) or spectrophotometer is placed above or below the product conveyed at the required speed to continuously measure the color of the surface of the object. How to measure color.

[0006]

However, the above-mentioned conventional inspection method can attain a prima facie purpose under conditions corresponding to the principle, but it is difficult to inspect the color difference of a sheet-like object online. Is not sufficient in terms of inspection efficiency.

That is, in the method using the luminous flux of the laser beam, since the laser beam is monochromatic light, it is possible to detect scratches that scatter the light and adhesion of foreign matter, but it is not possible to detect a color difference.

The method using an image sensor requires an image analysis device and requires data processing by software, so that the time required for detection is long and the equipment cost is high. Insufficient performance makes it impossible to perform inspections with an accuracy comparable to human eyes, and it is also not possible to meet the required speed of the process.

Further, in regard to a method using a color sensor or a spectrophotometer, a number of methods and devices have been proposed, but color difference inspection data obtained by measuring the color of a sheet-like object is graphed and detected. The color difference value that can be judged whether or not the value is within the allowable range,
The current situation is unprecedented. Especially in the case of a long inspection length such as a sheet-like object, it is not possible to instantly determine whether the cause of the color unevenness is the lightness unevenness or the hue unevenness generated in the previous process, and to distinguish the judgment result in real time. It is important in improving online inspection efficiency.

An object of the present invention is to graph the color difference inspection data obtained by measuring the color of a sheet-like object and determine whether or not the detected color difference values are within a permissible range. It is an object of the present invention to provide a color difference inspection device for a sheet-like material that uses a color sensor and that can be performed in real time.

[0011]

A color difference inspection apparatus for a sheet-like object of the present invention comprises a conveying means for causing a sheet-like object to be inspected to travel in a belt shape, the conveying means, an input section for inputting inspection conditions, and an inspection condition. A first display unit for displaying, and a first control unit for controlling the first output unit for outputting the initial condition, at least one color sensor for measuring the color of the sheet-like object surface, and the color sensor. The colorimetric data obtained by the control is processed to detect the color difference of the sheet-like material, and the second display section for displaying the detected color difference and the second output section for outputting the detected color difference are controlled. , A first control means and a second control means capable of mutually communicating with each other, wherein the second control means processes colorimetric data obtained by the color sensor to obtain a reference color value. Color difference value ΔE with
And the lightness deviation value ΔL ^* are obtained, and these ΔE and ΔL
^{The *} value is graphed, and it is determined whether or not each of the ΔE and ΔL ^* values is within the preset allowable range, and the result is displayed on the second display unit in real time, and the inspection is completed. The feature is that the graph and the determination result are sometimes printed out by the second output unit.

According to the color difference inspection apparatus of the present invention, the color difference ΔE
Since a graph showing the fluctuations of both the lightness deviation value ΔL ^* and the lightness deviation value ΔL ^* is displayed, it is possible to know whether the cause of the color unevenness is due to the difference in lightness or the difference in hue.
Since it is determined whether or not each of the E and ΔL ^* values is within the preset allowable range, it is possible to determine the color unevenness in real time. At the end of the inspection, these graphs are printed out at the end of the inspection, so that the inspection efficiency is remarkably improved.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIG.
This will be described with reference to FIGS.

FIG. 1 is a general flow chart showing a general inspection procedure in an online color difference inspection when a color sensor is used. That is, conditions such as the product name of the object to be inspected, the inspection date, and the inspection speed are input, and the reference value, that is, the reference color value for detecting the color difference is set. Turn on the power of the transport system to start the measurement.

The color measurement of the color sensor is carried out while identifying the measurement points because data is collected at certain intervals of the object to be inspected. If it is a measurement point, the color is measured to collect data and display it on the screen. When the measurement end point comes, the conveyance system power is turned off, the results are totaled, the required color difference variation graph is printed out, and the inspection ends.

FIG. 2 is a block diagram of the color difference inspection apparatus of the present invention. In FIG. 2, the color difference inspection device includes a first CPU (1) as a first control means and a second CPU (7) as a second control means.

The first CPU (1) has a conveying means (4), an input section (5) for inputting inspection conditions, a first display section (2) for displaying inspection conditions, a color difference judgment notifying device (18), and , A first output section (3) for outputting the initial condition is connected. Transport means
(4) is a conveyance motor for traveling the sheet-like object, drive motors for focusing the color sensor on the color measurement position,
It includes devices such as a meandering prevention device for sheet-like material, a wrinkle spreading device, and a tension control device (all not shown). The input unit (5) is a device for inputting inspection conditions, and includes a keyboard, bar code reader, voice input device,
It is composed of a switch input device for instructing monitoring / stop / forward / reverse of the transport system. The first display section (2) is a CRT for constantly monitoring the inspection conditions before / during / after the inspection, and the first output section (3) is a printer for printing out the initial conditions.

The second CPU (7) has a plurality of color sensors (10), a second display section (8) for displaying the detected color difference, and a second output section (9) for outputting the detected color difference. Are connected. Normally, a plurality of color sensors (10) are used, and in particular, in order to perform color difference inspection of a sheet-shaped material, it is desired to intensively check the color difference between the center and both ends in the width direction of the sheet-shaped material to detect the presence or absence of color unevenness. Therefore, it is most efficient to install the three color sensors side by side in the direction perpendicular to the sheet running direction. It is also easy to directly connect an input device (not shown) to the second CPU (7),
The CPU (7) has a communication line (16) with the first CPU (1).
Connected to the first CPU (1)
Since the input condition from (5) can be transmitted to the second CPU (7), the second CPU (7) does not need an input device. The second display unit (8) is a graphic display, and displays the data obtained by successive colorimetry in a graph. By displaying the graph, it is possible to know the variation of the color difference in real time during the inspection. In addition, the second display (8) is
For each of the values of E and ΔL ^* , the determination result of whether or not the value is within a preset allowable range is also displayed. This makes it possible to know not only the change in color difference but also the determination result as to whether or not the change in color difference is within a preset allowable range. The second output section (9) prints out the graph and the like displayed on the screen of the second display section (8) at the end of the measurement.

FIG. 3 shows a conceptual diagram of the system configuration of the color difference inspection apparatus of the present invention, and the block diagram will be described in more detail.

In FIG. 3, the first CPU (1), the first display section (2), the first output section (3), etc. are composed of, for example, a personal computer PC-9801 (manufactured by NEC). The first CPU (1) is provided with a built-in storage device of about 100 MB (megabyte) for recording inspection conditions, data and the like. Also, connect the input / output interface board and A / D conversion board to the input / output (I / O) terminal of the first CPU (1) to transfer the system (drive motor).
(4) and switch input signals are controlled.

Further, in order to use a plurality of color sensors (10), it is necessary to calibrate each color sensor (10). For this calibration, absolute value calibration (white plate calibration) and measurement object are used. There is a corresponding standard color calibration. In order to do this efficiently, the calibration plate (11) attached to the linear motor (13)
(12) to the position of each color sensor (10) until the horizontal arm (14)
It is configured to automatically move along. The first CPU (1) also controls the linear motor (13).

The input section (5) is provided with an inspection condition input device such as a keyboard or a bar code reader, and starts / stops / stops the transport system.
It is composed of a switch input device for controlling forward / backward movement.

Next, the second CPU (7) processes the color measurement by the plurality of color sensors (10) and the data obtained by the color measurement, and in real time, the second display section (graphic display) (8 ) Is displayed as a color difference variation graph. For this reason, it is necessary to perform color measurement (three color sensors) and data display (three data) simultaneously and sequentially, so that the second CPU (7) can perform multitask processing well known in the computer field. For example, a 68020 (manufactured by Motorola) processor system based on OS 9 (operating system) is used.

The first output section (3) prints out the inspection conditions and the detailed numerically analyzed data by the initial condition output section, if necessary. The second output section (9) prints out the color difference variation graph displayed on the second display section (8) when the measurement is completed.

The first CPU (1) includes a color difference determination notification device (1
8) is connected. In the color difference determination notification device (16), a green, yellow or red lamp is turned on according to the determination result. That is, for example, if the final determination result is "color difference", the red lamp is lit, if it is a warning, the yellow lamp is lit, and if there is no color difference, the green lamp is lit.

The first CPU (1) and the second CPU (7) are connected by, for example, an RS232C communication line (16), and transmission of inspection conditions, colorimetric commands, etc. (first CPU (1) → second CP
U (7)) and transmission of data obtained by the color sensor (second CPU (7) → first CPU (1)) are bidirectionally performed.

The second CPU (7) and three color sensors
(10) is also connected by the RS232 communication line (17), respectively, and command data and the like are bidirectionally transmitted.

Since the apparatus of the present invention is configured as described above, the color difference inspection of the sheet-like material can be easily performed on-line, and the color measurement, the data display and the result determination can be performed in real time, so that the inspection efficiency can be improved. Is improved.

Next, the function of the color difference inspection apparatus system of the present invention will be described with reference to the flow charts of FIGS. 4 and 5.
FIG. 5 is a continuation of FIG.

In the flow charts of FIGS. 4 and 5, the first CPU side (for example, PC-9801 control side) and the second CP side
The operation on the U side (for example, the 68020 control side) is shown separately. Since the first CPU and the second CPU are connected by the RS232C communication line, the first CPU in the flowchart
It is defined that the condition command or data at that time is transmitted from the side or the second CPU side in the direction of the dotted arrow.

Explaining the first CPU side, when the power is turned on, the initial state is set and the inspection condition etc is input. In order to eliminate input errors, barcode input is used as much as possible, and the inspection date, inspection time, and the like are automatically set by the first CPU. It is efficient to input a predetermined value for the inspection speed and to input the set speed only when necessary. If all these conditions are set, first
The condition set by the CPU is transmitted to the second CPU.

Next, it is checked whether or not white calibration is performed.
This is for calibrating the absolute value of the colorimetric value of the color sensor, and is a necessary operation for what is currently called a color sensor. As a general rule, it should be done before the measurement as much as possible, but in normal use, calibration several times a day is sufficient. This white calibration plate is fixed to the linear motor as shown in FIG. 3, and it is only necessary to move it to the position of the three color sensors. Similarly, the reference color calibration is necessary to reduce the error between devices of each color sensor so that a plurality of color sensors exhibit the same colorimetric value when measuring the same object. This operation has an optimum calibration method according to the color sensor used (for example,
As described in JP-A-62-142239), no specific method will be mentioned here.

Therefore, here, it is defined that the operation for eliminating (strictly minimizing) the inter-device error of a plurality of color sensors is the reference color calibration.

Since the reference color calibration is to measure the color of the reference sample as the measurement object, the colorimetric value obtained at this time is stored in the storage device as the reference color value. If the reference color calibration of the same measurement object has already been performed, the corresponding data is retrieved from the storage device and set. Here, CIE, L ^* a ^* b ^* color system (197
6), the reference color value is shown as (L _o ^* a _o ^* b _o ^* ). On the side of the first CPU, selection is made as to whether the reference color value is set by the reference color calibration or the data retrieval from the storage device.

When the reference color value setting confirmation signal is finally issued from the second CPU side, the condition setting up to the color measurement on the first CPU side is completed.

When it is confirmed that there is no abnormality in the transport system or peripheral equipment, and the inspection start signal is input by the switch, the transport system motor is turned on and the sheet-like object enters the traveling state, and at the same time, the second CPU side. A start command is transmitted to.

While the color sensor is actually measuring the color,
The operation on the first CPU side is mainly to check the detection of an abnormal signal in the transport system, or to receive the colorimetric data sent from the second CPU and store the data in the storage device. When an abnormal signal is detected, the transport system is stopped and waits.
If not, check if the measurement is complete. When the end signal is obtained, the transport system is stopped and the end signal is sent to the second CP.
The data is transmitted to U, the necessary data is processed, and the data is printed out to the first output unit.

As described above, the first CPU mainly controls the transport system during color measurement. During the inspection, the inspection conditions and the like are still displayed on the first display unit so that the inspector can always confirm the contents.

Next, the second CPU side will be described.
The initial state is set when the power is turned on. When the inspection condition is received from the first CPU, the presence / absence of a white calibration signal is next checked. If yes, white calibration is performed (actual operation depends on the color sensor used, and description thereof is omitted here). At this time, this system is equipped with a linear motor that moves the white calibration plate to the position of each color sensor, and calibration can be performed in order. When finished, the first CPU
To the end signal.

Next, it is checked whether or not the reference color is calibrated. If there is, the reference sample is moved by the linear motor and calibration is performed in order as in the case of white calibration. Then, at this point, a reference color value (L _o ^* a _o ^* b _o ^* ) for inspecting the color difference of the measured object is set on the second CPU side.
After that, the setting confirmation signal is transmitted to the first CPU, and the setting before measurement is completed. Next, the presence or absence of a measurement start signal is checked.

The operation of the second CPU after receiving the measurement start signal is to identify the colorimetric points of the sheet-like object, measure the colors of a plurality of color sensors simultaneously, and collect the colorimetric data. Then, it is displayed as a color difference variation graph on the second display section in real time. At this time, in the colorimetry of the present system, a method is adopted in which a plurality of data obtained at regular intervals are combined into one block of data. For example, data obtained by measuring 5 points at 1 m intervals is averaged, and the averaged colorimetric value is used as a representative point of 4-5 m after running. By doing this, in the case of a long inspection object such as a sheet-like object, data is actually taken in fine detail, and the necessary and sufficient number of data is displayed, and the number of data is compressed. There is also an advantage that it can be recorded.

In order to measure the length of the sheet material, a rotary encoder (not shown) is attached to the conveyance system motor,
It can be measured by counting the well-known number of pulses.

In the color difference variation graph, it is necessary for process control to know in real time whether the color unevenness is due to lightness (shading) or the hue is due to hue. Therefore, in the present invention, two color difference variation graphs of ΔE and ΔL ^* are displayed simultaneously. That is, it is possible to determine whether the color unevenness is the brightness unevenness or the hue unevenness based on the degree of variation of each of ΔE and ΔL ^* . That is, as shown in Table 1, it is possible to estimate the cause of the color unevenness defect based on the magnitude relationship between ΔE and ΔL ^* .

[0044]

[Table 1]

If the color difference unevenness tendency of the entire sheet-like material is understood by the above method, the color difference determination of the sheet-like material is simultaneously performed. Usually, the judgment is made after the inspection is completed, but for those having many hues such as fabric, the color difference judgment value greatly differs depending on the hue. Therefore, it is efficient to set a color difference allowable range in advance and to judge and display "color difference" for those exceeding the range so that the inspection efficiency is high.

FIG. 6 shows that the ΔE and Δ
FIG. 7 shows an example of a color difference variation graph in which two color difference variation graphs of L ^* and a color difference determination result are simultaneously shown.

That is, FIG. 6A is for the color difference value ΔE, and is the length position (unit m) VS.
7 is a graph showing a color difference value ΔE. In this graph, the horizontal solid line at the scale of ΔE = 2.0 represents the color difference allowable range in this case. Therefore, if the colorimetric ΔE value appears above this line (ΔE> 2.0), there is a color difference (marked by X), and the value is extremely close to this line (for example, ΔE
= 1.5-2.0), there is a color difference warning (△ mark), and when there is no color difference (for example, ΔE <1.5), it is displayed in real time like the ○ mark, so it is immediately judged. You can know the result. In addition, according to this result, in the color difference determination notification device, the green, yellow, or red lamp is turned on as described above.

FIG. 6B is for the lightness deviation value ΔL ^* , and is a graph showing the length position (unit m) VS. lightness deviation value ΔL ^* of the sheet-like material. In this graph, the horizontal solid lines at the scales of ΔL ^* = + 1.5 and −1.5 represent the color difference allowable range in this case. However, since the color difference determination result is determined based on both the lightness and the saturation (hue) as a whole, on the graph of ΔL ^* , ○, Δ,
No cross mark is shown. However, since the range of | ΔL ^* | is shown, it is possible to determine at a glance whether the cause of the color unevenness of the inspected object is due to the lightness or the hue.

FIG. 7 shows a woolen fabric having a length of 55 m and a width of 1.6 m, and a fabric speed of 35 m, which is obtained by the color difference inspecting apparatus having such a structure.
6 is an example of a color difference variation graph output when a color difference inspection is performed by traveling at a speed of / minute.

The upper graph in FIG. 7 is a graph showing the variation of the color difference value ΔE, that is, a graph showing the length position (unit m) VS. color difference value ΔE of the woolen fabric. The lower graph is a graph showing the variation of the lightness deviation value ΔL ^* , that is, a graph showing the length position (unit m) VS. lightness deviation value ΔL ^* of the woolen fabric. In these graphs, the data measured by the three color sensors are recorded at regular intervals. The line of $ mark (ΔE = 1.8) in the graph showing the color difference value ΔE is the color difference allowable range. Also, for each point that represents colorimetric data, ○, △,
The color difference determination result of the X mark (there is no X mark in this example) is displayed. By reading these fluctuations, it is possible to immediately determine whether the color difference defect is caused by the hue unevenness or the brightness unevenness, and at the same time, the color difference determination result can be known. The display of both graphs on the CRT can be accommodated in a necessary and sufficient size. In addition,
Numerical values and the like in the above graph are examples of conditions, color difference determination results, and the like that are output as necessary.

[0051]

As described above, according to the color difference inspection apparatus of the present invention, when performing the color difference inspection of the sheet-like material, the first and second control means control the transport system, the input system, and the plurality of colors. Simultaneous color measurement of sensors is possible, and ΔE
Since two kinds of color difference variation graphs of ΔL ^* and ΔL ^* are displayed in real time, it is possible to immediately perform qualitative color unevenness discrimination as to whether the color difference defect is caused by hue unevenness or brightness unevenness, and The judgment result can be known at the same time. Therefore, the apparatus of the present invention is an extremely efficient sheet-shaped material color difference inspection apparatus.

[Brief description of drawings]

FIG. 1 is a general flowchart showing a general inspection procedure in an online color difference inspection when a color sensor is used.

FIG. 2 is a configuration block diagram of a color difference inspection device of the present invention.

FIG. 3 is a conceptual diagram of a system configuration of a color difference inspection device of the present invention.

FIG. 4 is a flowchart for explaining the function of the color difference inspection device system of the present invention.

FIG. 5 is a flowchart for explaining the function of the color difference inspection apparatus system of the present invention. FIG. 4 is a continuation of FIG. 4.

FIG. 6 is an output example of a color difference variation graph by the color difference inspection apparatus of the present invention.

FIG. 7 is an output example of a color difference variation graph by the color difference inspection apparatus of the present invention.

[Explanation of symbols]

 (1) ... first control means (2) ... first display section (3) ... first output section (4) ... conveying means (5) ... input section (7) ... second control means (8) ... second Display unit (9) Second output unit (10) Color sensor (15) Sheet material (18) Color difference determination notification device

Claims (1)

[Claims] 1. A conveyance means (4) for causing a sheet-like material (15) to be inspected to travel in a strip shape, the conveyance means (4), an input section (5) for inputting inspection conditions, and a display for displaying inspection conditions. 1 display unit (2) and a first control unit (1) for controlling the first output unit (3) for outputting the initial condition, and at least one unit for measuring the color of the surface of the sheet (15). A color sensor (10) and a second display unit for processing the colorimetric data obtained by controlling the color sensor (10) to detect the color difference of the sheet material and displaying the detected color difference ( 8) and first control means for controlling the second output section (9) for outputting the detected color difference
(1) is a color difference inspection device composed of a second control means (7) capable of mutually communicating, and color measurement data obtained by the color sensor (10) in the second control means (7). Is processed to obtain a color difference value ΔE and a lightness deviation value ΔL ^* from the reference color value, the values of ΔE and ΔL ^* are graphed, and each of the values of ΔE and ΔL ^* falls within a preset allowable range. It is judged whether or not it is the value of, and displayed in real time on the second display part (8), and at the end of the inspection, these graphs and judgment results are printed out by the second output part (9). The sheet-like material color difference inspection device.