Method and apparatus for clipping coefficient values after application of each wavelet transform

• US 20030206661A1
• Filed: 03/06/2001
• Published: 11/06/2003
• Est. Priority Date: 02/15/2001
• Status: Active Grant

• Current Assignee: Edward L. Schwartz, Kok G.I. Wu, Martin Boliek, Michael J. Gormish
• Original Assignee: Edward L. Schwartz, Kok G.I. Wu, Martin Boliek, Michael J. Gormish
• Inventors: Gormish, Michael J., Schwartz, Edward L., Boliek, Martin, Wu, Kok Gi
• Granted Patent: US 6,898,325 B2
• Time in Patent Office: Days
• US Class Current: 382/248
• CPC Class Codes: G11B 27/036 Insert-editing
• CPC Class Codes: H04N 19/10 using adaptive coding
• CPC Class Codes: H04N 19/115 Selection of the code volume for a coding unit prior to coding
• CPC Class Codes: H04N 19/117 Filters, e.g. for pre-processing or post-processing sub-band filter banks H04N19/635
• CPC Class Codes: H04N 19/124 Quantisation
• CPC Class Codes: H04N 19/126 Details of normalisation or weighting functions, e.g. normalisation matrices or variable uniform quantisers
• CPC Class Codes: H04N 19/129 Scanning of coding units, e.g. zig-zag scan of transform coefficients or flexible macroblock ordering [FMO]
• CPC Class Codes: H04N 19/146 Data rate or code amount at the encoder output
• CPC Class Codes: H04N 19/147 according to rate distortion criteria rate-distortion as a criterion for motion estimation H04N19/567
• CPC Class Codes: H04N 19/152 by measuring the fullness of the transmission buffer
• CPC Class Codes: H04N 19/154 Measured or subjectively estimated visual quality after decoding, e.g. measurement of distortion use of rate-distortion criteria H04N19/147
• CPC Class Codes: H04N 19/162 User input
• CPC Class Codes: H04N 19/17 the unit being an image region, e.g. an object
• CPC Class Codes: H04N 19/172 the region being a picture, frame or field
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/34 Scalability techniques involving progressive bit-plane based encoding of the enhancement layer, e.g. fine granular scalability [FGS]
• CPC Class Codes: H04N 19/36 Scalability techniques involving formatting the layers as a function of picture distortion after decoding, e.g. signal-to-noise [SNR] scalability
• CPC Class Codes: H04N 19/40 using video transcoding, i.e. partial or full decoding of a coded input stream followed by re-encoding of the decoded output stream
• CPC Class Codes: H04N 19/42 characterised by implementation details or hardware specially adapted for video compression or decompression, e.g. dedicated software implementation H04N19/635 takes precedence
• CPC Class Codes: H04N 19/423 characterised by memory arrangements H04N19/433 takes precedence
• CPC Class Codes: H04N 19/426 : using memory downsizing methods
• CPC Class Codes: H04N 19/45 : performing compensation of the inverse transform mismatch, e.g. Inverse Discrete Cosine Transform [IDCT] mismatch
• CPC Class Codes: H04N 19/46 : Embedding additional information in the video signal during the compression process H04N19/517, H04N19/68, H04N19/70 take precedence
• CPC Class Codes: H04N 19/593 : involving spatial prediction techniques
• CPC Class Codes: H04N 19/61 : in combination with predictive coding
• CPC Class Codes: H04N 19/619 : the transform being operated outside the prediction loop
• CPC Class Codes: H04N 19/63 : using sub-band based transform, e.g. wavelets
• CPC Class Codes: H04N 19/635 : characterised by filter definition or implementation details
• CPC Class Codes: H04N 19/64 : characterised by ordering of coefficients or of bits for transmission
• CPC Class Codes: H04N 19/645 : by grouping of coefficients into blocks after the transform
• CPC Class Codes: H04N 19/647 : using significance based coding, e.g. Embedded Zerotrees of Wavelets [EZW] or Set Partitioning in Hierarchical Trees [SPIHT]
• CPC Class Codes: H04N 19/70 : characterised by syntax aspects related to video coding, e.g. related to compression standards
• CPC Class Codes: H04N 19/85 : using pre-processing or post-processing specially adapted for video compression
• CPC Class Codes: H04N 19/86 : involving reduction of coding artifacts, e.g. of blockiness

Abstract

A method and apparatus for clipping coefficient values after application of each wavelet transform is described. In one embodiment, the method comprises applying an inverse wavelet transform to data repeatedly for a plurality of decomposition levels, and clipping, after each application of the inverse wavelet transform, any value generated as a result of application of the inverse wavelet transform that exceeds a predetermined range associated with that decomposition level subband of the inverse wavelet transform.

Claims

1. A method comprising:

applying an inverse wavelet transform to data repeatedly for a plurality of decomposition levels; and

clipping, after each application of the inverse wavelet transform, any value generated as a result of application of the inverse wavelet transform that exceeds a predetermined range associated with that decomposition level subband of the inverse wavelet transform.

2. The method defined in claim 1 wherein the inverse wavelet transform comprises a 5,3 wavelet transform filter.

3. The method defined in claim 1 wherein the inverse wavelet transform comprises a 9,7 wavelet transform filter.

4. An article of manufacture comprising one or more recordable media having executable instructions stored thereon which, when executed by a machine, cause the machine to:

apply an inverse wavelet transform to data repeatedly for a plurality of decomposition levels; and

clip, after each application of the inverse wavelet transform, any value generated as a result of application of the inverse wavelet transform that exceeds a predetermined range associated with that decomposition level, subband and inverse wavelet transform.

5. The article of manufacture defined in claim 4 wherein the inverse wavelet transform comprises a 5,3 wavelet transform filter.

6. The article of manufacture defined in claim 4 wherein the inverse wavelet transform comprises a 9,7 wavelet transform filter.

7. An apparatus comprising:

means for applying an inverse wavelet transform to data repeatedly for a plurality of decomposition levels; and

means for clipping, after each application of the inverse wavelet transform, any value generated as a result of application of the inverse wavelet transform that exceeds a predetermined range associated with that decomposition level, subband and inverse wavelet transform.

8. The apparatus defined in claim 7 wherein the inverse wavelet transform comprises a 5,3 wavelet transform filter.

9. The apparatus defined in claim 7 wherein the inverse wavelet transform comprises a 9,7 wavelet transform filter.

10. A method comprising:

applying a forward wavelet transform to input data in a 4;

x;

x format to generate encoded data, where x is not equal to 4; and

quantizing level 1 coefficients in high-low (HL) and high-high (HH) subbands to zero, such that the encoded data resembles 4;

4;

4 formatted data.

11. The method defined in claim 10 further comprising quantizing level 1 coefficients in a low-high (LH) subband to zero.

12. The method defined in claim 11 wherein the input data is 4:

1;

1 formatted data.

13. The method defined in claim 10 wherein the input data is 4:

2;

2 formatted data.

16. The apparatus defined in claim 11 wherein the input data is 4:

1;

1 formatted data.

17. The apparatus defined in claim 10 wherein the input data is 4:

2;

2 formatted data.

14. An apparatus comprising:

means for applying a forward wavelet transform to input data in a 4;

x;

x format to generate encoded data, where x is not equal to 4; and

means for quantizing level 1 coefficients in high-low (HL) and high-high (HH) subbands to zero, such that the encoded data resembles 4;

4;

4 formatted data.

15. The apparatus defined in claim 14 further comprising means for quantizing level 1 coefficients in a low-high (LH) subband to zero.

18. An article of manufacture comprising one or more recordable media having executable instructions stored thereon which, when executed by a machine, cause the machine to:

apply a forward wavelet transform to input data in a 4;

x;

x format to generate encoded data, where x is not equal to 4; and

quantize level 1 coefficients in high-low (HL) and high-high (HH) subbands to zero, such that the encoded data resembles 4;

4;

4 formatted data.

19. The article of manufacture defined in claim 18 further comprising quantizing level 1 coefficients in a low-high (LH) subband to zero.

20. The article of manufacture defined in claim 19 wherein the input data is 4:

1;

1 formatted data.

21. The article of manufacture defined in claim 18 wherein the input data is 4:

2;

2 formatted data.