JPH0641862A - Method for testing color difference - Google Patents

Abstract

PURPOSE:To provide the highly efficient method for sheet-like products, so designed that simultaneous color measurement is made using plural color sensors to enable color measurement for the specified intervals on a sheet-like product at all times even in case its traveling speed is varied during its conveyance also give real-time test results. CONSTITUTION:In a color difference tester equipped with (A) a conveyance control section for a sheet-like product, (B) the 1st CPU 1 to control an input section 6 for test conditions, etc., display section 2 and output section 3, and (C) the 2nd CPU 7 to control the color measurement and display for plural color sensors 10, the input of rotary encoder 16 pulse rows are measured, and on reaching a specified number, color measurement is simultaneously made by the plural color sensors.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for inspecting a color difference of an object, and more particularly, a method for inspecting a color difference of a sheet-like material such as a woven fabric, a knit fabric, a non-woven fabric or a film mainly using a color sensor. Regarding

[0002]

2. Description of the Related Art Generally, industrial products such as cloth, film and board,
For example, in the process of dyeing woolen fabrics or cotton fabrics, color unevenness may occur due to uneven dispersion of dyes, partial coloring may occur due to overheating or contamination of foreign substances, or stains that turn brown due to oil or the like may occur. .
Such color unevenness, stains, etc. occur locally and suddenly, and are considered to be fatal defects in the appearance of industrial products.
The current situation is to inspect visually. Therefore, the labor required for inspection is large, and in order to rationalize it,
Conventionally, the following inspection methods are known. (1) Scanning the light flux of the laser beam at a high speed in a direction perpendicular to the product (measurement object) conveyance direction, and focusing on the point that the reflectance of the abnormal part changes with respect to the normal part, to detect scratches etc. To do. (2) A television camera using an image sensor scans the surface of the product, extracts an image signal and processes it to obtain a color unevenness signal. (3) A photoelectric colorimeter (color sensor) or a spectrophotometer is arranged above or below a product conveyed at a required speed,
The surface color of an object is continuously measured.

[0003]

However, in the above-mentioned conventional inspection method, although it is possible to attain a purpose for a condition corresponding to the principle, it is possible to check the color difference of the 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. In addition, the method using an image sensor requires an image analysis device and requires data processing by software, which increases the time required for detection and increases the equipment cost, and TV cameras have a poor color discrimination performance. It is not enough to perform inspections comparable to the human eye, and it is also not possible to meet the required speed of the process. Furthermore, many methods and devices have been proposed for the method of using a color sensor or a spectrophotometer.However, as a color difference test for a sheet-like material, in a multipoint color measurement method, the color sensor is caused to emit light at regular intervals. The method of color measurement is adopted.
With this method, when the inspection speed changes, the interval of the colorimetric data changes, so there is a problem that data comparison cannot be performed even on the same sheet-like object. Further, regarding the colorimetric method using a plurality of color sensors, there is no disclosure regarding improving the online inspection efficiency. Therefore, in the present invention, a plurality of color sensors are used to detect the color difference of a sheet-like material such as a fabric and a film, and a plurality of CPUs are used to control the transport system and the color measurement / display system. In a color difference inspection device with a control structure, the rotary encoder pulse input is counted, and when a preset number is reached, multiple color sensors are simultaneously measured to detect the color difference during the transportation of the measured object. It is an object of the present invention to provide a color difference inspection method with improved inspection efficiency that can display the color difference data in real time.

[0004]

In order to solve the above-mentioned problems, the present invention is an apparatus for inspecting on-line the color unevenness etc. of a sheet-like object such as a woven fabric or a film conveyed at a required speed. A transport unit that allows the sheet-like object to travel in a strip shape, an input unit that inputs the inspection conditions etc, a first display unit that displays the inspection conditions, a first output unit that outputs the results, and these transport units, input units, and the first A display unit, a first CPU for controlling the first output unit, and a plurality of color sensors located above or below the sheet-like object, connected to the color sensors, and connected to the first CPU via a communication line. Become second
The second CPU counts the rotary encoder pulse input, processes the colorimetric measurement of the controlled color sensor and the read data, detects the color difference of the sheet-like material and displays it, and outputs the result. And a second output section that operates.

[0005]

The colorimetric data of the sheet-like object is measured at the same timing, and the colorimetric data is always measured at constant intervals regardless of the traveling speed. Furthermore, because the control system using multiple CPUs is used, it is possible to easily control the transport system, inspection condition input, real-time screen display, output of results, etc., and obtain the information you want to know in an instant by inspection. The inspection efficiency can be significantly improved.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a general inspection procedure in an online color difference inspection when a color sensor is used.
It is a Flow Chart. That is, conditions such as the product name of the object to be measured, 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. The power of the transport system is turned on and the measurement is started. Since the color measurement of the color sensor collects data at certain fixed time intervals, the inspection can be performed while identifying the measurement points. If it is a measuring point, the color is measured to collect data and display it on the screen. When the measurement end point comes, the power of the conveying system is turned off, the results are totaled, and the necessary color difference variation graph is printed out. FIG. 2 shows a basic system configuration block diagram in which this procedure is applied to a color difference inspection device for a sheet-like material to improve inspection efficiency. First, this system has a plurality of CPUs. (First CPU and Second CPU) As a (peripheral) device connected to the first CPU, there is a carrying section (driving section),
This is a drive motor that moves a sheet-like object and a drive motor that focuses the color sensor on the color measurement position.
It also includes mechanical devices such as meandering prevention, wrinkle extension, and tension control (neither is shown). Next, there is an input unit, which is a device for inputting inspection conditions, and includes a keyboard, a bar code reader, a voice input device, and a switch input device for instructing start / stop / forward / backward movement of the transport system. Furthermore, the first display unit (CR) for constantly monitoring the inspection conditions before / after / after the inspection
T) and includes a first output unit (printer) that prints out inspection conditions and results. As a device connected to the second CPU, in order to perform color difference inspection of a plurality of color sensors, especially sheet-like objects, it is desired to intensively check the color difference between the center and both sides to detect the presence or absence of color unevenness. The most efficient arrangement method is to install three color sensors vertically to the. Next, it is easy to directly connect an input device (not shown) to the second CPU, but a communication line is connected to the second CPU between the first CPU and the input unit connected to the first CPU. Since the input condition can be transmitted to the second CPU, no input device is required for the second CPU. Further, it is important for the inspection to know the variation of the color difference in real time during the inspection. Therefore, the data obtained by successive color measurement is displayed in a graph.
It has a display unit (graphic display). And in order to control the timing of color measurement of multiple color sensors, the pulse output terminal of the rotary encoder is
It is connected to the input terminal of the second CPU. This rotary encoder is installed on a shaft such as a motor that runs a sheet-like object. It can be said that the most efficient inspection device configuration is that the graph etc displayed on the screen is printed out at the same time when the measurement is completed.

FIG. 3 shows a conceptual diagram of the system configuration of the present invention, and the block diagram will be described in more detail. 1st CP
The U, the first display unit, the first output unit, and the like are configured by, for example, a personal computer PC-9801 (manufactured by NEC). The first CPU is provided with a built-in storage device of about 100 MB (megabytes), and is configured to record inspection conditions, data and the like. Further, an input / output interface board and an A / D conversion board are connected to the input / output (I / O) terminals of the first CPU to control the carrier system (driving motor) and switch input signals. Further, in order to use a plurality of color sensors, it is necessary to calibrate each color sensor, and there are absolute value calibration (white plate calibration) and reference color calibration according to an object to be measured. In order to do this efficiently, the calibration plate installed in the linear motor is automatically moved to the position of each color sensor. This linear motor is also controlled by the first CPU (PC-9
801) is in charge. The input unit is composed of an inspection condition input device such as a keyboard and a bar code reader, and a switch input device for controlling start / stop / forward / reverse command of the transport system. Next, the second CPU controls color measurement by a plurality of color sensors, processes the data obtained by the color measurement, and displays the color difference variation graph on the second display unit (graphic display) in real time. There is. For this reason, it is necessary to perform color measurement (three color sensors) and data display (three colors) simultaneously and sequentially. Therefore, the second CPU configuration is well-known in the computer field, for example, OS9 which can perform multi-task processing. A 68020 (Motorola) processor system based on (operating system) is used. That is, the pulse output of the rotary encoder is connected to the input terminal of the second CPU, and the traveling distance of the sheet-like object is measured by counting the number of pulses. For example, when 30 pulses are output by one rotation of the rotary encoder, how much traveling distance it corresponds to depends on the diameter of the transport roller driven by the motor of the transport system installed. That is, when traveling about 30 cm per revolution, one interval of the pulse train of the rotary encoder reaches 1 cm. The first output unit prints out inspection conditions and detailed numerically analyzed data as necessary. The second output unit prints out the color difference variation graph displayed on the second display unit when the measurement is completed. The first CPU and the second CPU are connected by, for example, an RS232C communication line, and transmission of inspection conditions, colorimetric commands and the like (first CPU → second CPU), transmission of data obtained by the color sensor (second CPU → first CPU) ) Etc. are performed in both directions. The second CPU and three color sensors are also R
It is configured to be connected by the S232C communication line and to transmit command data and the like bidirectionally. With the above configuration, color difference inspection can be performed more quickly, and color measurement data of multiple color sensors can be controlled by rotary encoder pulses, so that color measurement data can be obtained even when the transport speed changes. Can be at regular intervals. Furthermore, it is a device that can improve inspection efficiency such as color measurement and data display in real time.

Next, the function of the present invention will be described with reference to the flowcharts of FIGS. Note that C and D in the flowchart of FIG. 4 are connected to C and D of FIG. In the flowcharts of FIGS. 4 and 5, the operations on the first CPU side (for example, PC-9801 control side) and the second CPU side (for example, 68020 control side) are shown separately. 1st C
Since the PU and the second CPU are connected by the RS232C communication line, it is defined that the condition command and data at that time are transmitted from the first CPU side or the second CPU side in the flowchart 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 erroneous input, the barcode is input as much as possible, and the inspection date and inspection time are automatically set by the first CPU. Further, it is efficient to input a predetermined value as the inspection speed and input the set speed only when necessary. If all of these conditions are set, the conditions set by the first CPU are transmitted to the second CPU. Next, check whether to perform white calibration. This is to calibrate the absolute value of the colorimetric value of the color sensor, which is a necessary operation for what is called the current color sensor. As a general rule, it should be done before color 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.
All you have to do is move to the position. Similarly, the reference color calibration is necessary to reduce the inter-device error of each color sensor so that a plurality of color sensors show the same colorimetric value when the same object is colorimetrically measured. Since this operation has an optimum calibration method according to the color sensor used, a specific method will not be mentioned. (There is, for example, Japanese Patent Laid-Open No. 62-142239). Therefore, here, the operation for eliminating (strictly minimizing) the error between a plurality of color sensors is defined as 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 has already been performed, the corresponding data is retrieved from the storage device and set. Here, CIE L * a * b
* Using the color system (1976), the standard color value is (L0 * a0 *
b0 *). 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 second CPU side finally outputs a reference color value setting confirmation signal, the first CPU
The condition setting up to color measurement on the PU side is completed. After confirming that there is no abnormality in the transport system or peripheral equipment, when the inspection start signal is input by the switch, the transport system motor turns on and the sheet-like object enters the running state, and at the same time the color measurement starts on the second CPU side. Command is transmitted. While the color sensor is actually measuring the color, the operation on the first CPU side mainly checks the detection of the abnormal signal of the transport system or receives the color measurement data sent from the second CPU and stores the data in the storage device. The action of doing. When an abnormal signal is detected, the transportation system is stopped and stands by. If not, check if the measurement is complete. When the end signal is obtained, the carrier system is stopped, the end signal is transmitted to the second CPU, and the necessary data is processed to the first CPU.
Print out to the output section. As described above, the first CPU
Mainly controls the transport system during color measurement. During the inspection, the inspection conditions etc. are still displayed on the first display section so that the inspector can always confirm the contents.

The second CPU side will be described. When the power is turned on, the initial state is set. When the inspection condition is received from the first CPU, the presence or absence of a white calibration signal is checked next.
If yes, perform white calibration. (The actual operation depends on the color sensor used, and the description is omitted.) 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 is performed in order. Can be done. When finished, it sends an end signal to the first CPU. Next, the presence or absence of reference color calibration is checked. When there is, the reference sample is moved by the linear motor and calibration is performed in order as in the case of white. At this point, the reference color value (L0 * a0 * b0 *) for inspecting the color difference of the measured object is set on the second CPU side. After this, a setting confirmation signal is sent to the first CPU to complete the setting before measurement.
Next, the presence or absence of the measurement start signal is checked. The operation of the second CPU after receiving the measurement start signal is mainly to identify the colorimetric points of the sheet-like object, measure the colors of a plurality of color sensors at the same time, collect the colorimetric data, and That is to display it in real time as a color difference variation graph on the second display unit. First, the sheet length is measured with a rotary encoder pulse. When the number of pulses set in advance, for example N = 100, is 100 and the number of input pulses is a colorimetric point, a colorimetric command is issued to three color sensors. If one pulse corresponds to 1 cm, the measurement is made every 100 cm. At this time, in the color measurement of this 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 to 5 m. By doing this, in the case of a long inspection object such as a sheet-like object, data is actually taken in detail and in detail, the necessary and sufficient number of data is displayed, and the data is compressed and recorded. There is also an advantage that it can be done. When the sheet-shaped object reaches the set length, it is confirmed that the colorimetry has been completed, and the color difference variation graph displayed on the second display section is immediately output to the second output section (printer). With such a structure, the inspection efficiency is remarkably improved.

FIG. 6 is an example of a color difference variation graph output by the woolen fabric color difference inspection device having such a configuration. A woolen fabric with a length of 55 m and a width of 1.6 m is applied at a cloth speed of 35 m /
It is an inspection result when the vehicle is run in minutes. The horizontal axis represents the length (unit: m) and the vertical axis represents the color difference value ΔE, and the data measured by the three color sensors are recorded at regular intervals. The graph below is also plotted with the vertical axis representing the color difference on the lightness axis (L * axis). The above numerical values and the like are examples of conditions, color difference determination results, and the like that are output as necessary.

[0011]

As described above, according to the present invention, when a color difference inspection of a sheet-like object is performed, a plurality of CPUs are used to control the transport system, the input system, etc. and count the number of rotary encoder pulses. Simultaneous color measurement of the color sensors of the above, and each CPU controlling data collection and color difference variation graph display, so that even if the traveling speed changes during conveyance, the sheets are always measured at fixed intervals. Color can be made and color difference (color unevenness, stain et
c) The inspection results were obtained, and it became possible to use it as an extremely efficient sheet color difference inspection device.

[Brief description of drawings]

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

FIG. 2 shows a basic system configuration block diagram of a sheet-shaped material color difference inspection apparatus according to the present invention.

FIG. 3 shows a conceptual diagram of a system configuration.

FIG. 4 shows an operation flowchart of a sheet-shaped material color difference inspection device including two CPUs as an embodiment of the present invention.

FIG. 5 shows an operation flowchart of a sheet-shaped material color difference inspection device including two CPUs as one embodiment of the present invention (continuation of FIG. 4).

FIG. 6 is an output example of a color difference variation graph.

[Explanation of symbols]

1: 1st CPU, 2: 1st display part, 3: 1st output part,
4: Transport drive motor, 5: Transport system drive control input section (switch), 6: Inspection condition input section (keyboard),
7: 2nd CPU, 8: 2nd display part, 9: 2nd output part, 1
0: color sensor, 11: white calibration plate, 12: reference sample of measurement object, 13: linear motor, 14: guide rail, 15: sheet-like object, 16: rotary encoder

Claims (1)

[Claims] 1. A first CPU that controls a transport unit for running a sheet-like object in a band, an input unit for inputting inspection conditions, a first display unit for displaying inspection conditions, and a first output unit for outputting results. And a plurality of color sensors located above or below the sheet-like material, and connected to the color sensors,
And a second CU connected to the first CPU via a communication line
A color difference inspection including a second display unit that processes the color measurement of the color sensor and the read data by P to detect and display the color difference of the sheet-like object, and the second output unit that outputs the graph result. In the device, a color difference inspecting device including a device having a second output unit is connected to the second CPU, and the number of pulses input from the rotary encoder is counted, and when the preset number is reached, the second CPU measures the number. A color difference inspection method characterized by recognizing color points and performing simultaneous color measurement of a plurality of color sensors.