JPH0815025A - Color difference inspection method - Google Patents

Abstract

PURPOSE:To further promote process management and analysis by displaying a plurality of graphs of changes in color difference of colorimetric data with color sensors, color difference values from a reference color value and deviation values of brightness in real time to be printed out when a measurement is ended. CONSTITUTION:A power of conveying a textile 11 is turned ON with the start of operation to start a measurement. Pulses entering a CPU3 from a rotary encoder 13 are counted and a running range is calculated to identify a color measuring point and when the color measuring point is identified, a colorimetry is performed. A plurality of colorimetric data are grouped at a fixed interval to make one block of data and collected to be shown on a display section 4. A graph of changes in color difference has a running range plotted on an axis of abscissa and color difference values and a color difference of a brightness axis on an axis of ordinate, which enables the learning in real time of whether uneven color is attributed to brightness or to hue. This allows the obtaining of information effective for process management and analysis along with quality control of products.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting the color difference of an object, and more particularly to a method for inspecting the color difference of mainly textiles using a color sensor.

[0002]

2. Description of the Related Art Generally, in the process of dyeing industrial products such as cloth, film and board, for example, wool fabric or cotton fabric, color unevenness occurs due to non-uniform dispersion of dye, or partial coloring due to overheating or foreign matter mixing. Or stains that are colored brown by oil or the like. Such color unevenness, stains, etc. occur locally and suddenly, and are considered to be fatal defects in the appearance of industrial products. It is the current situation. For this reason, the labor required for the inspection is large, and the following inspection methods are conventionally known in order to rationalize the labor. (1) Scans the luminous flux of the laser beam at a high speed in a direction perpendicular to the transport direction of the product (measured object), and focuses on the point where the reflectance of the abnormal part changes from that of the normal part to detect scratches, etc. I do. (2) A television camera using an image sensor scans the surface of a product, extracts and processes an image signal, and obtains a color unevenness signal. (3) A photoelectric colorimeter (color sensor) or a spectrophotometer is arranged above or below the product conveyed at a required speed, and the color of the surface of the object is continuously measured.

[0003]

However, in the above-mentioned conventional inspection method, although it is possible to achieve a purpose for the condition corresponding to the principle, it is possible to inspect the color difference of the fabric online. Not efficient enough. 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 a flaw that scatters light and to attach a foreign substance, but cannot detect a color difference. In addition, the method using an image sensor uses an image analysis device and requires data processing by software, which increases the time required for detection, increases equipment costs, and causes television cameras to have insufficient color discrimination performance. Therefore, it is not possible to perform an inspection comparable to the human eye, and it is not possible to meet the required speed of the process. Further, many methods and devices have been proposed for the method of using a color sensor or a spectrophotometer, but as a general color difference inspection, a graph showing a variation of a color difference ΔE with a reference color value is used. Often. This has the advantage of being able to immediately determine the color difference from the standard product in terms of quality control.
However, in the case of long objects such as fabrics, the inspection length is long and the cause of the color unevenness is to instantly determine whether the unevenness of lightness or the unevenness of hue that occurs in the dyeing or processing process in the previous process is used for process control or This is important for the analysis.

[0004]

In order to solve the above-mentioned problems, the present invention is a method for on-line inspection of color unevenness of a long object such as a woven fabric which is conveyed at a required speed. Conveying section for running a strip in a strip shape Keyboard for inputting inspection conditions, input section for inputting start / stop, display section for displaying inspection condition or result graph, output section for outputting results, and conveyance of these Section, an input section, a display section, an output section, and a plurality of color sensors located above or below the elongated object, and a long object surface between the color sensor and the elongated object. There is a calibration mechanism that automatically calibrates the color sensor by one or more calibration objects that move in parallel with the reference color value, and two variations of a color difference ΔE with a reference color value and a lightness deviation value ΔL *. By displaying the graph, color unevenness It aims to provide a color difference inspection device that immediately determines whether the cause is due to lightness or hue and is useful not only for product quality control but also process control and analysis.

[0005]

By displaying the variation graphs of both the color difference ΔE and the lightness deviation value ΔL, it is possible to determine in real time whether the cause of color unevenness is due to the difference in lightness or the difference in hue. The CRT display can be displayed in a sufficiently large size, and the efficiency is improved because it is printed out at the end of the inspection. An embodiment of the present invention is shown in FIG.
-It will be explained with reference to FIG.

[0006]

1 is a schematic diagram of a basic system configuration of a color difference inspection apparatus using a plurality of color sensors proposed in the present invention. The CPU, display unit, output unit, etc. of the system are, for example, a personal computer PC-9801 (N
Made by EC). As a peripheral device connected to the CPU, there is a carrying unit (driving unit), and a linear motor that moves a carrying motor for driving a long object and a driving motor for focusing a color sensor to a color measurement position to move a calibration plate. It also includes mechanical devices such as motors, anti-meander, wrinkle-rolling, tension control (neither shown).
A rotary encoder is installed on the transport roller or the transport motor shaft in order to control the color measurement timing of the plurality of color sensors. These are C
It is controlled by connecting an input / output interface board and an A / D conversion board to the input / output (I / O) terminal of the PU. Further, the input unit is a device for inputting inspection conditions, and includes a keyboard, a bar code reader, a voice input device, and a start / start of a transport system.
It is composed of a switch input device for instructing stop / forward / reverse. A plurality (three in FIG. 1) of color sensors are installed perpendicular to the traveling direction of the long object. This is because, in the case of textiles and the like, the color difference between the left and right, that is, the medium rareness is accurately detected. The color sensor is connected to the CPU and controlled by a communication line such as RS-232C. The CPU is provided with a storage device of about 100 MB so that inspection conditions, data and the like can be recorded.

FIG. 2 shows an operation flowchart of the color difference inspection apparatus according to the present invention, and the details of the function will be described. First, conditions such as the product name of the object to be measured, the inspection date, and the inspection speed are input. Then, a reference value for performing the color difference inspection, that is, a reference color value is set. When the start signal is input, the carrier power is turned on and the measurement is started. When the measurement is started, it is checked whether it is the measurement inspection length. If it is not completed, whether the colorimetric point is reached or not is recognized by counting the pulses input from the rotary encoder to measure the traveling distance. If it is a color measurement point, color measurement is performed, data is collected and displayed on the CRT. At this time, in the embodiment of this system,
A method is used in which a plurality of data are collected at regular intervals for colorimetry to form one block of data. For example, 5 at 1m intervals
The point-color-measured data is averaged, and the average color-measured value is used as a representative point of 4 to 5 m. By doing this, in the case of a long object such as a woven fabric, data is actually taken in fine detail, and the necessary and sufficient number of data can be displayed, and the data can be compressed and recorded. There is also a merit to say.

The color difference variation graph can know in real time whether the color unevenness is due to the lightness (shading) or the hue, and provides effective information for process control and analysis as well as product quality control. Therefore, in the present invention, ΔE and Δ
Two L * color difference variation graphs are displayed simultaneously. That is, it is possible to determine whether the unevenness of lightness or the unevenness of hue can be discriminated by the degree of variation of each of ΔE and ΔL *. Table 1 shows △ E and △ L
It is possible to estimate the cause of the uneven color defect based on the magnitude relationship of.

[0009]

[Table 1]

When the inspection length comes and the measurement ends, the conveyance power is turned off, the results are totaled, and a color difference variation graph is printed out.

FIG. 3 is an example of a color difference variation graph output by the woolen fabric color difference inspection device having such a configuration. A woolen cloth 55 m long and 1.6 m wide is woven at a cloth speed of 35 m /
This 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 constant distance intervals. In the graph below, the vertical axis is similarly plotted for the color difference on the lightness axis (L * axis). Numerical values in the graph are examples of conditions, color difference determination results, and the like that are output as necessary.

[0012]

As described above, according to the present invention, when a color difference inspection is performed on a long object, especially a woven fabric, a plurality of color sensors are simultaneously measured for color difference ΔE from a reference color value. Since two kinds of color difference variation graphs of the lightness deviation value ΔL * are displayed in real time, it can be used as an extremely efficient color difference inspection device that can immediately perform qualitative determination of color unevenness due to lightness or unevenness due to hue. It has become possible.

[Brief description of drawings]

FIG. 1 shows a schematic diagram of a basic system configuration of a color difference inspection apparatus according to the present invention.

FIG. 2 is an operation flowchart of an online color difference inspection device using a color sensor.

[Fig. 3] Output example of color difference variation graph

[Explanation of symbols]

1 input unit, 2: keyboard, 3: CPU, 4: display unit,
5: output unit, 6: linear motor, 7: reference cloth calibration plate,
8: White calibration plate, 9: Color sensor, 10: Guide rail, 11: Fabric, 12X axis stage, 13: Rotary encoder

Claims (1)

[Claims] 1. A transport unit for running a long object in a strip shape,
An input unit for inputting inspection conditions, a display unit for displaying inspection conditions and results, and an output unit for outputting results, a CPU for overall control of these, and a CPU connected to this CPU and positioned above or below a long object. A color difference inspection device comprising a plurality of color sensors and a calibration mechanism section for calibrating the color sensors by one or more calibration objects that move between the color sensors and the elongated object parallel to the elongated object surface. In the color difference inspection method used, a plurality of color difference variation graphs of the color difference value ΔE between the colorimetric data obtained by the color sensor and the reference color value and the deviation value ΔL * of the brightness are displayed on the display unit in real time. Then, at the end of the measurement, the color difference inspection method is characterized in that these graphs are printed out to the output section.