A Model for Halftone Color Prediction from Microstructure

摘要

In this work, we take a microstructure model based approach to the problem of color prediction of halftones created using an inkjet printer. We assume absorption and scattering of light through the colorant layers and model the subsurface light scattering in the substrate by a Gaussian point spread function. We restrict our analysis to transparent substrates. To model the absorption and scattering of light through the colorant layers, we employ the Kubelka-Munk color mixing model. To model the scattering in the substrate and to predict the spectral distribution, we use a wavelength dependent version of the reflection prediction model developed by Ruckdeschel and Hauser. Using spectral distributions and ink weight measurements for transparencies completely and homogenously coated with colorants, we compute the absorption and scattering spectra of the colorants using the Kubelka-Munk theory. We train our model using measured spectral distributions and synthesized microstructure images of primary (created using only one colorant) ramps printed on transparent media. For each patch in the primary ramp, we synthesize a high-resolution halftone microstructure image from the halftone bitmap assuming dot profiles with Gaussian roll-offs, from which we compute a high-resolution transmission image using the Kubelka-Munk theory and the absorption and scattering spectra of the colorants. We then convolve this transmission image with the Gaussian point spread function of the transparent substrate to predict the average spectral distribution of the halftone. We use our model to predict the spectral distribution of a secondary (created using two colorants) ramp printed on the same media.