Method and apparatus for performing selective quantization by manipulation of refinement bits

• US 6,983,075 B2
• Filed: 03/06/2001
• Issued: 01/03/2006
• Est. Priority Date: 02/15/2001
• Status: Expired due to Fees

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Gormish, Michael J., Schwartz, Edward L., Boliek, Martin, Wu, Kok Gi
• Primary Examiner(s): Au, Amelia M.
• Assistant Examiner(s): SHERALI, ISHRAT I
• Application Number:
  US09/800,687
• Publication Number:
  US 20030210826A1
• Time in Patent Office: 1,764 Days
• Field of Search: 382/251, 382/253, 382/239, 382232-240, 382/243, 382/248, 382/176, 382/177, 375/240.03, 375/240.18, 375/240.23, 375/240.19, 375/240.11, 358/426.01, 358/426.16
• US Class Current: 382/251
• 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 performing selective quantization by manipulation of refinement bits is described. In one embodiment, the method comprises performing a refinement coding pass to bit-planes of a code block to create refinement bits and setting refinement bits to the more probable symbol (MPS).

Claims

1. A method comprising:

performing a refinement coding pass to bit-planes of a code block to create refinement bits, wherein the refinement bits are generated based on bits from coefficients that became significant in a significance propagation pass of a previous bit-plane;

identifying a target area of the refinement bits of the code block that is designated to maintain a predetermined quality of the target area; and

setting refinement bits to the more probable symbol (MPS) by setting the refinement bits of the code block that do not effect the predetermined quality of the target area to the MPS, while using actual values for the refinement bits that effect the predetermined quality of the target area, wherein the refinement bits set to the MPS are quantized as a result of setting refinement bits to the MPS,

wherein the target area comprises text in a background image, wherein the refinement bits that are set to MPS are those that do not effect the text of the background image for the last bitplane, while using the actual values for the refinement bits that effect the text of the background image.

2. The method defined in claim 1 wherein only a portion of the refinement bits in a code block are set to the MPS, and wherein the portion of the refinement bits set to the MPS is transmitted having a number of bits different than a number of bits of a remaining portion of the refinement bits.

3. The method defined in claim 1 wherein setting refinement bits to the MPS is performed to implement non-uniform quantization step sizes, wherein the refinement bits set to the MPS are quantized to a value different from values of the refinement bits without being set to the MPS within the code block.

10. The method defined in claim 1, wherein the refinement bits are set to the MPS to reduce distortion effects on a current frame due to a change of a rate distortion of the corresponding refinement bits of a previous frame.

11. The method defined in claim 1, wherein the refinement bits are set to the MPS to minimize distortion effects on a current frame due to a change of a rate distortion of the corresponding refinement bits of a previous frame.

4. An apparatus comprising:

means for performing a refinement coding pass to bit-planes of a code block to create refinement bits, wherein the refinement bits are generated based on bits from coefficients that became significant in a significance propagation pass of a previous bit-plane;

means for identifying a target area of the refinement bits of the code block that is designated to maintain a predetermined quality of the target area; and

means for setting refinement bits to the more probable symbol (MPS) including means for setting the refinement bits of the code block that do not effect the predetermined quality of the target area to the MPS, while using actual values for the refinement bits that effect the predetermined quality of the target area, wherein the refinement bits set to the MPS are quantized as a result of setting refinement bits to the MPS,

wherein the target area comprises text in a background image, wherein the refinement bits that are set to the MPS are those that do not effect the text of the background image for the last bitplane, while using the actual values for the refinement bits that effect the text of the background image.

5. The apparatus defined in claim 4 wherein only a portion of the refinement bits in a code block are set to the MPS, and wherein the portion of the refinement bits set to the MPS is transmitted having a number of bits different than a number of bits of a remaining portion of the refinement bits.

6. The apparatus defined in claim 4 wherein setting refinement bits to the MPS is performed to implement non-uniform quantization step sizes, wherein the refinement bits set to the MPS are quantized to a value different from values of the refinement bits without being set to the MPS within the code block.

12. The apparatus defined in claim 4, wherein the refinement bits are set to the MPS to reduce distortion effects on a current frame due to a change of a rate distortion of the corresponding refinement bits of a previous frame.

13. The apparatus defined in claim 4, wherein the refinement bits are set to the MPS to minimize distortion effects on a current frame due to a change of a rate distortion of the corresponding refinement bits of a previous frame.

7. An article of manufacture comprising at least one recordable media storing executable instructions thereon which, when executed by a processing device, cause the processing device to:

perform a refinement coding pass to bit-planes of a code block to create refinement bits, wherein the refinement bits are generated based on bits from coefficients that became significant in a significance propagation pass of a previous bit-plane,

identify a target area of the refinement bits of the code block that is designated to maintain a predetermined quality of the target area, and

set refinement bits to the more probable symbol (MPS) by setting the refinement bits of the code block that do not effect the predetermined quality of the target area to the MPS, while using actual values for the refinement bits that effect the predetermined quality of the target area, wherein the refinement bits set to the MPS are quantized as a result of setting refinement bits to the MPS,

wherein the target area comprises text in a background image, wherein the refinement bits that are set to MPS are those that do not effect the text of the background image for the last bitplane, while using the actual values for the refinement bits that effect the text of the background image.

8. The article of manufacture defined in claim 7 wherein only a portion of the refinement bits in a code block are set to the MPS, and wherein the portion of the refinement bits set to the MPS is transmitted having a number of bits different than a number of bits of a remaining portion of the refinement bits.

9. The article of manufacture defined in claim 7 wherein setting refinement bits to the MPS is performed to implement non-uniform quantization step sizes, wherein the refinement bits set to the MPS are quantized to a value different from values of the refinement bits without being set to the MPS within the code block.

14. The article of manufacture defined in claim 7, wherein the refinement bits are set to the MPS to reduce distortion effects on a current frame due to a change of a rate distortion of the corresponding refinement bits of a previous frame.

15. The article of manufacture defined in claim 7, wherein the refinement bits are set to the MPS to minimize distortion effects on a current frame due to a change of a rate distortion of the corresponding refinement bits of a previous frame.

16. A method, comprising:

identifying a target region of refinement bits of a code block generated from a magnitude refinement pass based on bits from significant coefficients of a significance propagation pass of a previous bit-plane; and

setting one or more refinement bits of the code block that do not significantly effect resolution of the target region to a more probable symbol (MPS), such that the one or more refinement bits are quantized with respect to other refinement bits that effect the resolution of the target region,

wherein the target region comprises text in a background image, wherein the refinement bits that are set to MPS are those that do not effect the text of the background image for the last bitplane, while using the actual values for the refinement bits that effect the text of the background image.

17. The method of claim 16, wherein the refinement bits that effect the resolution of the target region are set using actual values of the respective refinement bits.

18. The method of claim 16, wherein the refinement bits set to the MPS are quantized to a value different from values of the refinement bits without being set to the MPS within the code block.

19. The method of claim 16, wherein the portion of the refinement bits set to the MPS is transmitted having a number of bits different than a number of bits of a remaining portion of the refinement bits.

20. The method of claim 16, wherein the refinement bits are set to the MPS to reduce distortion effects on a current frame due to a change of a rate distortion of the corresponding refinement bits of a previous frame.

21. The method of claim 16, wherein the refinement bits are set to the MPS to minimize distortion effects on a current frame due to a change of a rate distortion of the corresponding refinement bits of a previous frame.

22. An article of manufacture comprising at least one recordable media storing executable instructions thereon which, when executed by a processing device, cause the processing device to:

identify a target region of refinement bits of a code block generated from a magnitude refinement pass based on bits from significant coefficients of a significance propagation pass of a previous bit-plane, and

set one or more refinement bits of the code block that do not significantly effect resolution of the target region to a more probable symbol (MPS), such that the one or more refinement bits are quantized with respect to other refinement bits that effect the resolution of the target region,

wherein the target region comprises text in a background image, wherein the refinement bits that are set to MPS are those that do not effect the text of the background image for the last bitplane, while using the actual values for the refinement bits that effect the text of the background image.

23. An apparatus, comprising:

means for identifying a target region of refinement bits of a code block generated from a magnitude refinement pass based on bits from significant coefficients of a significance propagation pass of a previous bit-plane; and

means for setting one or more refinement bits of the code block that do not significantly effect resolution of the target region to a more probable symbol (MPS), such that the one or more refinement bits are quantized with respect to other refinement bits that effect the resolution of the target region,

wherein the target region comprises text in a background image, wherein the refinement bits that are set to MPS are those that do not effect the text of the background image for the last bitplane, while using the actual values for the refinement bits that effect the text of the background image.