H - Electricity – 04 – N
Patent
H - Electricity
04
N
350/33
H04N 7/34 (2006.01) G06T 9/00 (2006.01)
Patent
CA 1325672
APPARATUS AND METHOD OF ATTENUATING DISTORTION INTRODUCED BY PREDICTIVE CODING IMAGE COMPRESSION ABSTRACT OF THE DISCLOSURE The present invention relates to a predictive coding method and related apparatus which (a) computes a value D repres- enting the difference between an original graylevel value for a current pixel and a predicted value for the current pixel; (b) associates each successive range of D values to a re- spective quantization level, each quantization level QN hav- ing a respective QN value representing the range corresponding thereto; (c) sets a respective QERR value to D for the current pixel, when the QN value is zero; (d) re-maps m QERR values to n (n ? m) MERR values; (e) assigns to the value MERR=0 those QERR values in which ¦QERR¦?(+Q1VALUE)/2 sums the MERR values for successive pixels in a QN=Q0 region; and (f) adjusts the QN value from the value of Q0 by the value of Q1 for a pixel at which the summed value reaches a predefined threshold. QN values, ad- justed as appropriate, are subjected to entropy coding com- pression and decompression. In the decompression process, pixel values are reconstructed. According to the invention, the reconstructed values are subjected to a vertical filter in which a pixel having a reconstructed value I0 is filtered to have a value I'0=I0+[(I-1-I0)C-+(I+1-I0)C+] wherein C+ and C- are respective predefined clamping values, and wherein I-1 and I+1 are the respective reconstructed values of pixels adjacently below and adjacently above the current pixel.
562726
Gonzales Cesar A.
Pennebaker William B.
International Business Machines Corporation
Na
LandOfFree
Apparatus and method of attenuating distortion introduced by... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus and method of attenuating distortion introduced by..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus and method of attenuating distortion introduced by... will most certainly appreciate the feedback.
Profile ID: LFCA-PAI-O-1187744