Template selection for LUT inverse halftoning and application to color halftones

In a previous paper we have proposed a method for inverse halftoning of monochrome images. It is a look up table (LUT) based method, obtained from the histogram gathered from a few sample halftone images and corresponding original images. The method is extremely fast (no filtering is required) and the image quality achieved is comparable to the best methods known for inverse halftoning. The method does not depend on the specific properties of halftoning method, and can be applied to any halftoning method. In this paper, we discuss how to choose the template recursively for the LUT. Afterwards, we propose an LUT based inverse halftoning method for color halftones. Color inverse halftoning can be done independently for each color plane or the correlation between the planes can be exploited. We also show how to choose the template for color inverse halftoning.