Presented at the 1998 IEEE International Conference on Image Processing

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

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

Laboratory for Image and Video Engineering, Department of Electrical and Computer Engineering, Engineering Science Building, The University of Texas at Austin, Austin, TX 78712-1084 USA -

Paper - Talk - Software

Halftoning Research at UT Austin


We present an inverse halftoning algorithm for error diffused halftones. At each pixel, the algorithm applies a separable 7 x 7 FIR filter parameterized by the horizontal and vertical edge strengths computed from the local gradients. The algorithm requires entirely local operations, storage of 7 rows, and fewer than 300 arithmetic operations/pixel. The algorithm can be easily implemented in embedded software or hardware. We compare our algorithm with previously reported approaches to show that it delivers comparable PSNR and subjective quality at a fraction of the computation and memory requirements. A C implementation of the algorithm is available at

Last Updated 11/11/04.