Disk read technique

• US 7,167,589 B2
• Filed: 01/08/2003
• Issued: 01/23/2007
• 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:
  US10/339,138
• Publication Number:
  US 20030138155A1
• Time in Patent Office: 1,476 Days
• Field of Search: 382/233, 382/240, 382/248
• 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 comprising:

performing a disk read to obtain coefficients stored on a disk;

decoding coefficients read from the disk while other coefficients are read from the disk;

performing an inverse wavelet transform on decoded coefficients while reading other coefficients from disk and decoding still other coefficients; and

sending transformed image data resulting from performing the inverse wavelet transform.

2. The method defined in claim 1 wherein the transformed image data is sent to a printer.

3. The method defined in claim 1 wherein the transformed image data is sent to a display for display thereon.

4. The method defined in claim 1 wherein the codestream includes at least one header and a plurality of coding units, at least two of the coding units being ordered to include more important data earlier in the codestream than less important data.

5. The method defined in claim 4 wherein the more important data is coded in coefficient order.

6. The method defined in claim 4 wherein the size of the more important data enables the more important data to be read from disk as a single transfer.

7. The method defined in claim 4 wherein the less important data is buffered, embedded and written to disk.

8. The method defined in claim 4 wherein the amount of less important data written to disk is based on the transfer rate of the disk.

9. The method defined in claim 1 wherein decoding coefficients read from the disk performing an inverse wavelet transform on decoded coefficients are performed by a decompressor.

10. The method defined in claim 9 wherein a decompressor operates on bands of a page, one band at a time, using memory space allocated for the band of a page in an output image as workspace to perform the decoding of coefficients and apply the inverse wavelet transform.

11. The method defined in claim 10 wherein each of the bands is divided into coding units.

12. An apparatus comprising:

means for performing a disk read to obtain coefficients stored on a disk;

means for decoding coefficients read from the disk while other coefficients are read from the disk;

means for performing an inverse wavelet transform on decoded coefficients while reading other coefficients from disk and decoding still other coefficients; and

means for sending transformed image data resulting from performing the inverse wavelet transform.

13. The apparatus defined in claim 12 wherein the transformed image data is sent to a printer.

14. The apparatus defined in claim 12 wherein the transformed image data is sent to a display for display thereon.

15. The apparatus defined in claim 12 wherein the codestream includes at least one header and a plurality of coding units, at least two of the coding units being ordered to include more important data earlier in the codestream than less important data.

16. The apparatus defined in claim 15 wherein the more important data is coded in coefficient order.

17. The apparatus defined in claim 15 wherein the size of the more important data enables the more important data to be read from disk as a single transfer.

18. The apparatus defined in claim 15 wherein the less important data is buffered, embedded and written to disk.

19. The apparatus defined in claim 15 wherein the amount of less important data written to disk is based on the transfer rate of the disk.

20. The apparatus defined in claim 12 wherein decoding coefficients read from the disk performing an inverse wavelet transform on decoded coefficients are performed by a decompressor.

21. The apparatus defined in claim 20 wherein the decompressor operates on bands of a page, one band at a time, using memory space allocated for the band of a page in an output image as workspace to perform the decoding and apply the inverse wavelet transform.

22. The apparatus defined in claim 21 wherein each of the bands is divided into coding units.

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

performing a disk read to obtain coefficients stored on a disk;

decoding coefficients read from the disk while other coefficients are read from the disk;

performing an inverse wavelet transform on decoded coefficients while reading other coefficients from disk and decoding still other coefficients; and

sending transformed image data resulting from performing the inverse wavelet transform.

24. The article of manufacture defined in claim 23 wherein the codestream includes at least one header and a plurality of coding units, at least two of the coding units being ordered to include more important data earlier in the codestream than less important data.

25. The article of manufacture defined in claim 23 wherein decoding coefficients read from the disk and performing an inverse wavelet transform on decoded coefficients are performed by a decompressor.

26. The article of manufacture defined in claim 25 wherein the decompressor operates on bands of a page, one band at a time, using memory space allocated for the band of a page in an output image as workspace to perform the decoding and apply the inverse wavelet transform.

27. The article of manufacture defined in claim 26 wherein each of the bands is divided into coding units.