以多角度影像量測建立印刷品上光色彩模式

Establishment the Color Model of Glossy Varnish on Printed Matter by Multi-Angle Image Measurement

江瑞璋(Raymond Chiang)；孫沛立(Pei-Li Sun)

上光 ； 介電質 ； 色彩 ； 多角度 ； 高斯分配曲線 ； Varnish ； dielectric ； color ； multi-angle ； gaussian distribution

中華印刷科技年報

2022（2022 / 05 / 01）

71 - 78

繁體中文

印刷品上光部份常會引起鏡面反射現象，如採用標準測色機構45°／0°儀器量測反光部份將會呈現較暗的不合理現象，與視覺觀看上光印刷品會有較亮的情形正好相反。因此本研究採用曲面形多角度光源以模擬環境光源，並對無上光和有上光的四色印刷品取像分析後，不但可以得到與視覺相符合的反光色彩，而且可歸納出反光部份與無上光印刷品的轉換關係，其結果可由無上光的四色印刷品依據歸納後不同係數的高斯分配曲線模擬出上光品的色彩，將有助於上光印刷品之色彩量測及預測。另外，經由高倍電子顯微鏡的輔助分析，可得到同軸光及環形光源對反光的影像，以及3D微結構的立體重建出因絲網拉墨而產生紋理現象。

The glossy varnish on prints often causes specular reflection. If a color instrument of standard measuring mechanism 45° /0° is used to measure the reflective part, it will appear darker, which is exactly the opposite of the brighter situation when viewing the varnished printed matter visually. Therefore, in this study, a multi-angle light source was used to simulate the ambient light source. After image analysis of unvarnished and varnished four-color prints, the color of the varnished print can be simulated according to the Gaussian distribution curve from the uncoated four-color print.

1. Dorsey, J.,Rushmeier, H.,Sillion, F.(2008).Digital Modeling of Material Appearance.Morgan Kaufmann.
2. Kruschwitz, J.(2018).Field guide to colorimetry and fundamental color modeling.SPIE Press.
3. Kumar, A.,Choudhury, R.(2014).Principles of Colour and Appearance Measurement.Elsevier.
4. Schaaf, Crystal B.,Gao, Feng,Strahler, Alan H.,Lucht, Wolfgang,Li, Xiaowen,Tsang, Trevor,Strugnell, Nicholas C.,Zhang, Xiaoyang,Jin, Yufang,Muller, Jan-Peter,Lewis, Philip,Barnsley, Michael,Hobson, Paul,Disney, Mathias,Roberts, Gareth,Dunderdale, Michael,Doll, Christopher,d’Entremont, Robert P.,Hu, Baoxin,Liang, Shunlin,Privette, Jeffrey L.,Roy, David(2002).First operational BRDF, albedo nadir reflectance products from MODIS.Remote Sensing of Environment,83,135-148.
5. Tominaga, S.(1991).Surface Identification using the Dichromatic Reflection Model.IEEE Transactions on Pattern Analysis and Machine Intelligence,13(7),658-670.
6. Tominaga, S.,Tanaka, N.(2000).Estimating Reflection Parameters from a Single Color, Image.IEEE Computer Graphics and Applications,20(5),58-66.