In this paper, we present a new approach for inverse halftoning of error diffused halftones using a shearlet representation. We formulate inverse halftoning as a deconvolution problem using Kite et al.'s linear approximation model for error diffusion halftoning. Our method is based on a new M-channel implementation of the shearlet transform. By formulating the problem as a linear inverse problem and taking advantage of unique properties of an implementation of the shearlet transform, we project the halftoned image onto a shearlet representation. We then adaptively estimate a gray-scaled image from these shearlet-toned or shear-tone basis elements in a multi-scale and anisotropic fashion. Experiments show that, the performance of our method improves upon many of the state-of-the-art inverse halftoning routines, including a wavelet-based method and a method that shares some similarities to a shearlet-type decomposition known as the local polynomial approximation (LPA) technique.

Date Published: 4 September 2009
PDF: 10 pages
Proc. SPIE 7446, Wavelets XIII, 74460C (4 September 2009); doi: 10.1117/12.825640

Published in SPIE Proceedings Vol. 7446:
Wavelets XIII
Vivek K. Goyal; Manos Papadakis; Dimitri Van De Ville, Editor(s)