Presented at the 1999 IEEE Int. Conf. on Image Processing

Fast Rehalftoning and Interpolated Halftoning Algorithms with Flat Low-Frequency Response

Thomas D. Kite (1), Brian L. Evans (2), and Alan C. Bovik (2)

(1) Audio Precision, P. O. Box 2209, Beaverton, OR 97075-2209 USA

(2) Department of Electrical and Computer Engineering, Engineering Science Building, The University of Texas at Austin, Austin, TX 78712-1084 USA -

Paper - Presentation

Halftoning Toolbox for Matlab - Halftoning Research at UT Austin

We present fast, raster image processing algorithms for rehalftoning error diffused halftones and producing interpolated error diffused halftones. Rehalftoning converts a halftone created by one method into one created by another method. In interpolated halftoning, interpolation increases the image size before halftoning, e.g. for printing. Both rehalftoning and interpolated halftoning introduce blur and noise in the output image. To compensate for the blur, we use modified error diffusion which has a variable gain parameter to control the sharpness. We derive optimal formulas for the sharpness control parameter to to make the overall frequency response flat. The high-frequency noise is masked by error diffusion. The proposed algorithms yield halftones of high fidelity at a low computational cost.

Last Updated 11/08/04.