| US 7,590,298 B2 | ||
| Decompression with reduced ringing artifacts | ||
| Zhigang Fan, Webster, N.Y. (US); Ricardo de Queiroz, Brasilia (Brazil); Reiner Eschbach, Webster, N.Y. (US); and Shen-Ge Wang, Fairport, N.Y. (US) | ||
| Assigned to Xerox Corporation, Norwalk, Conn. (US) | ||
| Filed on Apr. 12, 2006, as Appl. No. 11/402,602. | ||
| Prior Publication US 2007/0242891 A1, Oct. 18, 2007 | ||
| Int. Cl. G06K 9/46 (2006.01) | ||
| U.S. Cl. 382—240 [382/233; 382/232] | 20 Claims |
| 1. A method of reducing artifacts introduced by a data compression procedure into digital image data to be printed, the method
comprising:
(a) receiving compressed digital image data;
(b) performing decompression of the digital image data;
(c) filtering the decompressed digital image data with a smoothing filter;
(d) applying a wavelet transform to the filtered digital image data to obtain transform coefficients;
(e) making an adjustment to the transform coefficients in the wavelet domain to guarantee that the wavelets of the resulting
image will generate the same compressed code; and
(f) recovering the image by applying an inverse wavelet transform to the adjusted transform coefficients.
|