Details:
Summary:
An iterative context dependent color halftoning algorithm is presented in this paper. Unlike the normal approach of halftoning a color image, in which the color separations of the original image are halftoned independently, the original color image is halftoned in a context dependent manner. The method is based on a monochromatic halftoning method that was presented earlier. The number of dots to be placed in each color separation of the final halftone image or in different parts of it is decided in advance. There is no dot in the initial halftoned image. In each iteration a new dot is placed at some particular position. The position of this dot depends on where the previous dots were placed. The final halftoned image is obtained after the predetermined numbers of dots have been placed in the color separations of the halftoned image. The strategy to reduce color noise and gain control over color gamut is to prevent dot-on-dot printing as much as possible. The color shifts that might occur because of this dot-off-dot printing strategy have to be compensated before halftoning. This transformation is dependent on some data for the printer with which the halftoned color image is supposed to be printed. The experiments verify that the color noise is notably smaller in the images that are halftoned by the proposed method compared to the images halftoned using the normal approach of halftoning color images.