Decoding with storage of less bits for less important data

• US 7,139,434 B2
• Filed: 01/08/2003
• Issued: 11/21/2006
• Est. Priority Date: 09/21/1994
• Status: Expired due to Fees

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Schwartz, Edward L.
• Primary Examiner(s): Tran, Phuoc
• Application Number:
  US10/339,501
• Publication Number:
  US 20030138156A1
• Time in Patent Office: 1,413 Days
• Field of Search: 382/233, 382/235, 382/240, 382/248, 382/244, 341/60, 375/240.19
• US Class Current: 382/233
• CPC Class Codes: G06F 17/148 Wavelet transforms
• CPC Class Codes: G06K 15/02 using printers
• CPC Class Codes: G06K 15/1865 by compressing the rasterized print data
• CPC Class Codes: H03M 7/30 Compression speech analysis-synthesis for redundancy reduction G10L19/00; for image communication H04N; Expansion; Suppression of unnecessary data, e.g. redundancy reduction
• CPC Class Codes: H04N 19/10 using adaptive coding
• CPC Class Codes: H04N 19/102 characterised by the element, parameter or selection affected or controlled by the adaptive coding
• CPC Class Codes: H04N 19/115 Selection of the code volume for a coding unit prior to coding
• CPC Class Codes: H04N 19/12 Selection from among a plurality of transforms or standards, e.g. selection between discrete cosine transform [DCT] and sub-band transform or selection between H.263 and H.264
• CPC Class Codes: H04N 19/122 Selection of transform size, e.g. 8x8 or 2x4x8 DCT; Selection of sub-band transforms of varying structure or type
• CPC Class Codes: H04N 19/124 Quantisation
• 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 19/13 Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC]
• CPC Class Codes: H04N 19/14 Coding unit complexity, e.g. amount of activity or edge presence estimation H04N19/146 takes precedence
• CPC Class Codes: H04N 19/146 Data rate or code amount at the encoder output
• CPC Class Codes: H04N 19/15 by monitoring actual compressed data size at the memory before deciding storage at the transmission buffer
• CPC Class Codes: H04N 19/156 Availability of hardware or computational resources, e.g. encoding based on power-saving criteria
• CPC Class Codes: H04N 19/162 User input
• CPC Class Codes: H04N 19/167 Position within a video image, e.g. region of interest [ROI]
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/18 the unit being a set of transform coefficients
• CPC Class Codes: H04N 19/184 : the unit being bits, e.g. of the compressed video stream
• CPC Class Codes: H04N 19/186 : the unit being a colour or a chrominance component
• CPC Class Codes: H04N 19/1883 : the unit relating to sub-band structure, e.g. hierarchical level, directional tree, e.g. low-high [LH], high-low [HL], high-high [HH]
• 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 19/42 : 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 19/46 : 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 19/60 : using transform coding
• CPC Class Codes: H04N 19/61 : in combination with predictive coding
• CPC Class Codes: H04N 19/635 : characterised by filter definition or implementation details
• 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 19/98 : Adaptive-dynamic-range coding [ADRC]
• CPC Class Codes: H04N 21/6377 : directed to server one-way streaming services wherein the source is controlled by the destination H04L65/613
• CPC Class Codes: H04N 21/658 : Transmission by the client directed to the server

Abstract

A method and apparatus for performing compression and/or decompression is described. In one embodiment, the present invention comprises a system having a buffer, a wavelet transform unit, and a coder. The wavelet transform unit has an input coupled to the buffer to perform a wavelet transform on pixels stored therein and to generate coefficients at an output. The coder is coupled to the wavelet transform unit to code the transformed pixels received from the buffer.

Claims

1. A method for decoding information in a codestream, the method comprising:

generating contexts for bits in a compressed data stream;

performing binary entropy decoding of bits in the compressed data stream to generate an embedded codestream of wavelet coefficients ordered with more important data followed by less important data, including storing less important data coefficients with less bits than used to represent a coefficient that is to undergo application of a reversible inverse transform; and

transforming coefficients into image data using a reversible inverse wavelet filter.

2. The method of claim 1 wherein the less important data comprises data bitplanes of a set of transformed coefficients.

3. The method defined in claim 1 wherein storing less important data coefficients during binary entropy decoding comprises:

reading a first amount of less important data from memory; and

writing a second amount of less important data greater than the first amount of data while reading the first amount of less important data to compensate for transformed bitplanes with less data in the lower order bitplanes of the set of transformed coefficients.

4. The method defined in claim 3 wherein writing a second amount of less important data occurs in response to a write operation that is performed for each bit of each coefficient in the less important data.

5. The method defined in claim 3 wherein bits required to store the first amount of less important data increase as the number of biplanes being examined decreases.

6. An apparatus for decoding information in a codestream, the method comprising:

means for generating contexts for bits in a compressed data stream;

means for performing binary entropy decoding of bits in the compressed data stream to generate an embedded codestream of wavelet coefficients ordered with more important data followed by less important data, including means for storing less important data coefficients with less bits than used to represent a coefficient that is to undergo application of a reversible inverse transform; and

means for transforming coefficients into image data using a reversible inverse wavelet filter.

7. The apparatus of claim 6 wherein the less important data comprises data bitplanes of a set of transformed coefficients.

8. The apparatus defined in claim 6 wherein the means for storing less important data coefficients during binary entropy decoding comprises:

means for reading a first amount of less important data from memory; and

means for writing a second amount of less important data greater than the first amount of data while reading the first amount of less important data to compensate for transformed bitplanes with less data in the lower order bitplanes of the set of transformed coefficients.

9. The apparatus defined in claim 8 wherein the means for writing a second amount of less important data operates in response to a write operation that is performed for each bit of each coefficient in the less important data.

10. The apparatus defined in claim 8 wherein bits required to store the first amount of less important data increase as the number of biplanes being examined decreases.

11. An article of manufacture having one or more recordable media storing instructions thereon which, when executed by a system, cause the system to decode information in a codestream by:

generating contexts for bits in a compressed data stream;

performing binary entropy decoding of bits in the compressed data stream to generate an embedded codestream of wavelet coefficients ordered with more important data followed by less important data, including storing less important data coefficients with less bits than used to represent a coefficient that is to undergo application of a reversible inverse transform; and

transforming coefficients into image data using a reversible inverse wavelet filter.

12. A method comprising:

generating contexts for bits in a compressed data stream;

performing binary entropy decoding of bits in the compressed data stream to generate an embedded codestream of wavelet coefficients ordered with more important data followed by less important data, wherein performing binary entropy decoding comprises

reading a first amount of less important data from memory, the less important data being less important portions of data bitplanes of a set of transformed coefficients, and

writing a second amount of less important data greater than the first amount of less important data while reading the first amount of less important data to compensate for transformed bitplanes with less data in the lower order bitplanes of the set of transformed coefficients; and

transforming coefficients into image data using a reversible inverse wavelet filter.

13. The method defined in claim 12 further comprising storing the coefficients bits of the less important data in packed bytes having less bits than each number of bits used to represent coefficients.