基于照相测色的镭射纸印品颜色检测方法研究

Color Detection Method of Printed Laser Paper via Imaging-based Color Measurement

中文关键词:  镭射纸印品  颜色检测  光谱重建  凸包算法  照相测量

英文关键词:printed laser paper  color detection  spectral reconstruction  convex hull algorithm  imaging-based measurement

中文摘要:

      目的 应用于精美包装的镭射纸表面具有光学微纳周期性结构，会对光产生散射、衍射和干涉等物理作用，难以采用分光光度计等传统颜色测量仪器对其颜色信息进行客观、准确及可重复测量。针对镭射纸印品颜色检测误差大、印品颜色稳定性控制难的问题，提出一种基于照相测量的镭射纸印品颜色稳定性检测方法。方法 首先对样本进行视觉标定，选定标准印品的可接受色差宽容度样本集;其次使用均匀漫射照明拍照系统拍摄标准印品及样本集的数字图像，并使用光谱重建方法重建样本的光谱反射率，依据色度学理论计算拍摄样本颜色数据;再使用凸包算法构建合格印品的可接受色差宽容度色域体及对应的椭球和椭圆;最后拍摄任意待测试印品的数字图像，并获取其颜色数据，通过色域体和待测印品的位置关系来判断待测印品的色相是否合格。结果 实验结果表明，所提方法能够实现镭射纸印品颜色的准确鉴别，对合格样品的检测精度能够达到100%，对不合格样品的检测精度能够达到90%以上。结论 可以实现视觉感知一致的镭射纸颜色稳定性检测，为镭射纸印品颜色的品控提供了解决方案。

英文摘要:

      Laser paper used for exquisite packaging has physical effects such as scattering, diffraction, and interference on its surface due to its optical microstructure, so that its color information is difficult to be measured objectively, accurately and repeatedly with traditional color measuring instruments such as spectrophotometer. spectrophotometers. To solve the problems of large color detection error and difficult control of color stability of printed laser paper, the work aims to propose an image-based color stability detection method of printed laser paper. Firstly, the samples were visually calibrated, and the acceptable color difference tolerance sample set of standard prints was selected. Secondly, the digital images of the standard prints and the selected samples were captured in a uniform illuminated imaging system, and the spectral reflectance of the samples was reconstructed by the spectral reconstruction method, and the color data of the captured sample were calculated according to chromaticity theory. Then, the convex hull algorithm was used to construct the color gamut of the acceptable color difference tolerance and the corresponding ellipsoid and ellipse. Finally, the digital image of any sample to be tested was captured, and its color data were calculated. Whether the color gamut of the print to be tested was qualified or not was judged by the positional relationship between the color gamut and the print to be tested. The experimental results showed that the method proposed could accurately identify the color of printed laser paper, with a detection accuracy of 100% for qualified samples and more than 90% for unqualified samples. It can achieve the stability detection of printed laser paper with consistent visual perception, providing a solution for the color control of printed laser paper.