Supercell dither masks with constrained blue noise interpolation

Abstract

When halftoning images using dither halftoning algorithms, traditional clustered dot dither algorithms trade off cluster cell size versus the number of gray levels. Supercell clustered dot dither algorithms are used to obtain a small cluster cell size while allowing a large number of gray levels to be rendered. However, commonly used supercell clustered dot dither algorithms have unpleasant patterns at certain gray levels. We present an algorithm to use constrained blue noise to correct such unpleasant patterns. We also illustrate how this algorithm can generate nonlinear dither masks which can compensate for dot gain without the use of a separate tone reproduction curve.