Removing harmonic distortion in tiled screens

When producing halftones with the screening technique, tiling is generally used to construct a screen of appropriate size with screens of small fixed size. Regular tiling and random tiling are two common tiling schemes used nowadays. The former scheme produces periodic screens which introduce harmonic distortion to the screening outputs while the latter may introduce blocking artifacts as the possible connections among adjacent blocks are too many for a training algorithm to train the small screens that are used for tiling. This paper addresses this issue and proposes a new tiling scheme that allows one to train small screens to construct large screens seamlessly. Simulation results show that a screen constructed with the proposed tiling screen bears blue noise characteristics, contains no blocking artifacts and little harmonic distortion.