基于iCAM的印刷品在线颜色复制质量的检测与评价

Online Detection and Evaluation of Print Color Reproduction Quality Based on iCAM

目的为了提高印刷品在线检测中颜色复制质量评价的准确性,构建基于iCAM图貌模型的印刷品在线检测色差计算模型。方法将印刷品在线检测系统中CCD相机拍摄的待检测样张按照墨区进行分区,基于iCAM图貌模型和IPT均匀颜色空间建立在线色差检测模型,并计算样张各个墨区的色差;设计视觉心理学实验评价样张各墨区颜色的复制质量;采用STRESS值评价基于iCAM的色差检测模型计算出的色差与视觉感受色差的一致性,并与基于CIELAB的色差进行比较,验证该模型的在线色差预测精度。结果基于iCAM的色差模型计算结果具有较高的视觉一致性,更符合视觉评价结果,且与传统色差模型相比,具有更高的在线色差检测精度。结论基于iCAM的印刷品在线检测色差计算模型考虑了人眼视觉的空间特性及色适应,适用于复杂观察条件,能提高印刷品在线检测中的色差检测精度,可用于实际生产中印刷品在线颜色复制质量的检测与评价。

The work aims to improve the accuracy of color reproduction quality assessment in online detection, and construct color difference calculation model of online print detection based on iCAM model. The images of printing samples obtained by CCD camera in the online detection system were divided according to the ink zones. Online color difference detection model was established based on iCAM model and IPT uniform color space, and then the color difference of every ink zone was calculated. Visual psychophysical experiment was designed to evaluate the color reproduction quality of every ink zone. STRESS value was used to evaluate the consistency between the color difference calculated by iCAM color difference detection model and the visual perception color difference. The color difference was also compared with the one calculated by CIELAB model, in order to verify the online color difference prediction accuracy of the model based on iCAM. The color difference model calculations based on iCAM had higher visual consistency, more in line with the visual evaluation results, and it had higher accuracy of online color difference detection compared with the traditional color difference model. Online detection color difference calculation model based on iCAM takes into account the spatial characteristics of human vision and chromatic adaptation, suitabled for complex observation conditions. It can improve the accuracy of online color difference detection; therefore, it can be used for online detection and evaluation of print color reproduction quality in actual printing production.