DECODING WITH EMBEDDED DENOISING

• US 20080285655A1
• Filed: 05/16/2008
• Published: 11/20/2008
• Est. Priority Date: 05/19/2006
• Status: Active Grant

• Current Assignee: Hong Kong University of Science and Technology
• Original Assignee: Hong Kong University of Science and Technology
• Inventors: Au, Oscar Chi Lim, Wong, Hon Wah, Guo, Liwei
• Granted Patent: US 8,831,111 B2
• Time in Patent Office: Days
• US Class Current: 375/240.16
• CPC Class Codes: H04N 19/44 Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder
• CPC Class Codes: H04N 19/51 Motion estimation or motion compensation
• CPC Class Codes: H04N 19/577 Motion compensation with bidirectional frame interpolation, i.e. using B-pictures
• CPC Class Codes: H04N 19/80 Details of filtering operations specially adapted for video compression, e.g. for pixel interpolation H04N19/635, H04N19/86 take precedence

Abstract

Methods and systems for denoising embedded digital video decoding. Prediction and residue block of a current frame are obtained from motion vector. Variance of residue block is calculated using prior reference blocks, and a causal temporal linear minimum square error estimator is used to calculate a filter coefficient. The residue block is modified using the filter coefficient, and an output digital bitstream of blocks of pixels of the current frame is produced using the modified residue block and prior denoised prediction value of prior frames.

Claims

1. A method for decoding digital signals, comprising the actions of:

receiving an input digital signal which is encoded;

estimating the noise and signal statistics of said digital signal and decoding said digital signal using motion compensation which references denoised reference blocks; and

accordingly outputting a decoded and denoised digital signal.

2. A method for decoding digital signals, comprising the actions of:

receiving an input digital signal which is encoded;

estimating the noise and signal statistics of said digital signal and decoding said digital signal, using two motion compensation operations;

wherein said two motion compensation operations use different respective reference frames which are differently denoised;

wherein said statistics is used to produce and output a decoded and denoised digital signal.

3. The method of claim 2, wherein said statistics includes a noise variance of said digital signal, which is estimated by averaging the noise variances of previously decoded reference signals.

4. The method of claim 3, wherein said action of decoding further comprising the actions of:

determining a prediction of said digital signal;

calculating a correction coefficient using said noise variance and signal statistics;

modifying said prediction using said correction coefficient to thereby produce and output a decoded and denoised digital signal.

5. The method of claim 4, wherein said prediction is determined by weighted averaging of multiple blocks of reference signals.

6. The method of claim 4, wherein said prediction is determined by using previously denoised reference signal.

7. The method of claim 4, wherein said prediction is determined by using both denoised and non-denoised reference signals.

8. The method for claim 4, wherein said correction coefficient is calculated by using a causal temporal linear minimum mean square error estimator (LMMSE).

9. The method for claim 8, wherein said action of modifying includes combined weighted linear modifications of said digital signal and weighted linear modification of said prediction using said correction coefficient.

10. A method for decoding digital video signals, comprising the actions of:

receiving an input bitstream of a video pixel which is encoded;

estimating signal and noise statistics of said video pixel, using two motion compensation operations;

wherein said two motion compensation operations use different respective reference frames which are differently denoised; and

decoding said video pixel wherein said statistics is used to produce and output a decoded and denoised digital video pixel.

11. The method of claim 10, wherein said statistics includes a noise variance of said video pixel, which is estimated by averaging the noise variances of previously decoded pixels in a reference frame.

12. The method of claim 11, wherein said action of decoding further comprising the actions of:

determining a prediction value of said pixel;

calculating a correction coefficient using said noise variance and said signal statistics; and

modifying said prediction using said correction coefficient, thereby to produce and output a decoded and denoised video pixel.

13. The method of claim 12, wherein said prediction is produced by weighted averaging blocks of pixels from different frames.

14. The method of claim 12, wherein said prediction is produced by using previously denoised pixel or block of denoised pixels of previous frame.

15. The method of claim 12, wherein said prediction is produced by using both denoised and non-denoised pixels in at least one reference frame.

16. The method of claim 12, wherein said correction coefficient is calculated by using a causal temporal linear minimum mean square error estimator (LMMSE).

17. The method for claim 16, wherein said action of modifying includes combined weighted linear modification of said video pixel and weighted linear modification of said prediction using said correction coefficient.

18-74. -74. (canceled)