IEEE Transactions on Image Processing, vol. 9, no. 9, pp. 1583-1592, Sep. 2000

A Fast, High Quality Inverse Halftoning Algorithm for Error Diffused Halftones

Thomas D. Kite, Niranjan Damera-Venkata, Brian L. Evans, and Alan C. Bovik

Department of Electrical and Computer Engineering, Engineering Science Building, The University of Texas at Austin, Austin, TX 78712-1084 USA
tomk@audioprecision.com - bevans@ece.utexas.edu - bovik@ece.utexas.edu

Software in C - Halftoning Toolbox for Matlab

Halftoning Research at UT Austin

Abstract

Halftones and other binary images are difficult to process with causing several degradation. Degradation is greatly reduced if the halftone is inverse halftoned (converted to grayscale) before scaling, sharpening, rotating, or other processing. For error diffused halftones, we present

a fast inverse halftoning algorithm, and
a new multiscale gradient estimator.

The inverse halftoning algorithm is based on anisotropic diffusion. It uses the new multiscale gradient estimator to vary the tradeoff between spatial resolution and grayscale resolution at each pixel to obtain a sharp image with a low perceived noise level. Because the algorithm requires fewer than 300 arithmetic operations per pixel and processes 7 x 7 neighborhoods of halftone pixels, it is well suited for implementation in VLSI and embedded software. We compare the implementation cost, peak signal-to-noise ratio, and visual quality with other inverse halftoning algorithms.

Last Updated 11/08/04.