1. Key Lab of Modern Optical Technologies of Ministry of Education, School of Optoelectronic Science and Engineering, Soochow University, Suzhou 215006, China
2. Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province, School of Optoelectronic Science and Engineering, Soochow University, Suzhou 215006, China
3. School of Computer Science and Technology, Soochow University, Suzhou 215008, China
Abstract：Variations in lighting conditions, differences in printing materials, deviations in-camera color filter arrays, or color responses easily affect the colorimetric measurements of cameras when detecting printed colors. Hyperspectral imagers can obtain the intrinsic reflectance curves of objects and coordinate with the chromaticity algorithm to effectively improve the accuracy of chromaticity measurement and can obtain the chromaticity value under various lighting environment conditions. To meet the demands of detecting color differences in printed matter, a tristimulus influence analysis model for each index of imaging chromaticity measurement system was proposed based on the mixed reflectance of printed matter. Key indices of this imaging colorimetric measurement system include signal-to-noise ratio, spectral resolution, smile, keystone, etc. To reduce the effects of non-uniformity, noise, and radiation standard transfer, uniformly distributed standard diffuse reflectance boards are used to directly establish the physical relationship between object reflectance and instrument detector pixel responses instead of traditional relative and absolute radiometric calibrations of imaging spectrometers. A push-broom type wide-format colorimetric imaging device (PBCID) has been developed based on Offner-type spectrometer components, and correction processing is avoided due to its low smile and keystone. According to the analysis model and CIEDE2000 color difference formula, the color difference caused by each device index is less than 0.3. Comparing the color measurement results of the PBCID and the reference instrument CM-700d on a 24-color standard card, spectral and chromatic accuracy can meet the requirements of discerning fine print color differences. After reflectance calibration, the spectral radiance response within the slit field of view of PBCID is uniform, and the measurement chromaticity uniformity is good, with a maximum color difference of 1.02. The average color difference of each color patch measured by the PBCID under different lighting sources is 1.56, indicating that the PBCID's color measurements are not affected by the light source. The analytical model for instrument indices' impact on chromatic measurements and the calibration process based on the reflectance boards provide a design basis and technical foundation for developing online wide-format imaging colorimetric instruments.
Key words：Printed matter color; Push-broom colorimetric imaging; Tristimulus value impact analysis model; Color difference; Reflectance calibration; Smile and keystone
陈静雪，魏愉城，周建康，朱嘉诚，沈为民. 用于印刷品的宽幅面高光谱颜色测量系统研究[J]. 光谱学与光谱分析, 2025, 45(02): 312-321.
CHEN Jing-xue, WEI Yu-cheng, ZHOU Jian-kang, ZHU Jia-cheng, SHEN Wei-min. Research on Wide Format Hyperspectral Color Measurement System for Printed Matter. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2025, 45(02): 312-321.
[1] Panák O, Drková M, Kailová N, et al. Measurement, 2018, 127: 554.
[2] Kinoshita J, Yamamoto K, Kuroda K. Optical Review, 2018, 25(1): 123.
[3] Luo S, Hong Z, Zheng Z, et al. SID Symposium Digest of Technical Papers, 2021, 52(S2): 266.
[4] Van Roy J, Keresztes J C, Wouters N, et al. Postharvest Biology and Technology, 2017, 129: 79.
[5] Khan M H, Saleem Z, Ahmad M, et al. Applied Sciences, 2020, 10(17): 5955.
[6] Wang S, Das A K, Pang J, et al. Food Chemistry, 2022, 382: 132343.
[7] Zhang J, Zhang X, Wu J, et al. Coloration Technology, 2021, 137(2): 166.
[8] Qiu K, Chen W, Zhou H, et al. Color Research & Application, 2021, 46(6): 1205.
[9] Ji Y, Li J, Zhou J, et al. Applied Optics, 2015, 54(3): 517.
[10] Guanter L, Segl K, Sang B, et al. Optics Express, 2009, 17(14): 11594.
[11] O'Shea R E, Laney S R, Lee Z. Applied Optics, 2020, 59(7): B18.
[12] Mouroulis P, Green R O, Chrien T G. Applied Optics, 2000, 39(13): 2210.
[13] Förster E, Cumme S, Kraus M, et al. Applied Optics, 2023, 62(19): 5170.
[14] Burt P J, Adelson E H. ACM Transactions on Graphics, 1983, 2(4): 217.
