In 1931, CIE (Committee on International Standards for Illumination) established a series of color space standards for representing the visible spectrum. The basic CIE color space standard is CIE_XYZ, which is based on the standard observer's visual abilities, meaning that it reflects the standard range of colors visible to the human eye. Based on CIE_XYZ, there are standard color spaces such as CIE_xyY, CIE_Lab, and CIE Lch.

At present, the most commonly used color space in the industry is the CIE Lab color space. In the CIE Lab color space, the L value represents the lightness of the color, the a value represents the green-red value of the color, and the b value represents the blue-yellow value of the color. It does not make much practical sense to judge a certain color simply by a set of Lab values, but when we compare two colors, we can judge the difference between them by the Lab difference of these two colors.

For example: a customer provided us with a standard color sample with a measured Lab value of 60/30/20, while the final product we actually produced measured a Lab value of 62/31/18, and the calculated Lab difference was +2/+1 respectively. /-2, we can know that the L value of the product is higher than the standard, that is, it is brighter, the a value is higher than the standard, that is, it is reddish, and the b value is lower than the standard, that is, it is bluish. By comparing the Lab value of the product and the standard color sample, we can You can easily know the color status of the current product.

In addition, through the two sets of Lab values, we can calculate the color difference between the two colors. If the color difference is greater than 1, our eyes can distinguish it. Therefore, we can set a certain tolerance range in advance. During quality control, the color difference between the measured sample and the standard color is within the tolerance range, which is a qualified product, and if it exceeds the range, it is an unqualified product. By using the Lab color space, our production control is digitized.

Analysis principle:

Automatically compare the color difference between the sample and the tested product, and output three sets of CIE_Lab data and four sets of color difference data of ΔE, ΔL, Δa, and Δb after colorimetry. The size of the ΔE total color difference, ΔL, is large, indicating white, small ΔL, black, Δa, red, small Δa, green, Δb, yellow, and Δb, blue.