Prediction of the spectral reflectance of laser-generated color prints by combination of an optical model and learning methods

Abstract

. Prediction of the spectral reflectance of laser-generated color prints by combination of an optical model and learning methods. Journal of the Optical Society of America. A Optics, Image Science, and Vision, Optical Society of America, 2015, 32 (9) Recent color printing technologies based on the principle of revealing colors on pre-functionalized achromatic supports by laser irradiation offer advanced functionalities, especially for security applications. However, for such technologies the color prediction is challenging, compared to classic ink-transfer printing systems. The spectral properties of the coloring materials modified by the lasers are not precisely known and may strongly vary, depending on the laser settings, in a nonlinear manner. We show in this study, through the example of the Color Laser Marking technology based on laser-bleaching of a mixture of pigments, that the combination of an adapted optical reflectance model and learning methods to get the model's parameters enables predicting the spectral reflectance of any printable color with rather good accuracy. Even though the pigment mixture is formulated from three colored pigments, an analysis of the dimensionality of the spectral space generated by CLM printing, thanks to a Principal Component Analysis decomposition, shows that at least four spectral primaries are needed for accurate spectral reflectance predictions. A polynomial interpolation is then used to relate RGB laser intensities with virtual coordinates of new basis vectors. By studying the influence of the number of calibration patches on the prediction accuracy, we can conclude that a reasonable number of 130 patches are enough to achieve good accuracy in this application.

Study on spectral reflectance model for color printing dot

“…A reflection prediction model based on the Kubelka-Munk theory further improves the accuracy 6,7 . Besides the methods combining optical properties with adaptive learning successfully predicted the spectral reflectance of laser printers 8 . However, such prediction models can only give a single predicted value of reflectance and cannot present the micro-morphology of dots on different substrates.…”

Application of Art in Computer Graphic Design

“…Give more weight to sensitive wavelengths for key matching, and give less weight to insensitive wavelengths. Even though there are already two different types of weight factors, they are unable to capture the variations in colour perception at different wavelengths [11].…”

Spectral and Color Changes of Ag/TiO2 Photochromic Films Deposited on Diffusing Paper and Transparent Flexible Plastic Substrates

“…An example of inkless printing system based on a bleachable dye mixture incorporated into the support, then colored under laser irradiation, has been recently studied. 1 In the present paper, we investigate another inkless printing technique applicable to soft supports such as white paper and transparent PET, coated with TiO 2 /Ag/TiO 2 thin films.…”