Fixed-rate block-based image compression with inferred pixel values

• US 6,775,417 B2
• Filed: 01/17/2002
• Issued: 08/10/2004
• Est. Priority Date: 10/02/1997
• Status: Expired due to Term

• Current Assignee: ATI International SRL (Advanced Micro Devices, Inc.), ATI Technologies ULC (Advanced Micro Devices, Inc.), S3 Graphics Co., Ltd. (HTC Corporation)
• Original Assignee: S3 Graphics Co., Ltd. (HTC Corporation)
• Inventors: Hong, Zhou, Nayak, Krishna S., Iourcha, Konstantine I.
• Primary Examiner(s): Do, Anh Hong
• Application Number:
  US10/052,613
• Publication Number:
  US 20030053706A1
• Time in Patent Office: 936 Days
• Field of Search: 382/166, 382/162, 382/232, 382/253, 725/146, 345/549, 345/550, 358/539
• US Class Current: 382/253
• CPC Class Codes: G06T 9/00 Image coding bandwidth or redundancy reduction for static pictures H04N1/41; coding or decoding of static colour picture signals H04N1/64; methods or arrangements for coding, decoding, compressing or decompressing digital video signals H04N19/00
• CPC Class Codes: G06T 9/005 Statistical coding, e.g. Huffman, run length coding
• 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 19/12 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 19/124 Quantisation
• 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 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/186 the unit being a colour or a chrominance component
• CPC Class Codes: H04N 19/436 using parallelised computational arrangements
• CPC Class Codes: H04N 19/91 Entropy coding, e.g. variable length coding [VLC] or arithmetic coding
• CPC Class Codes: H04N 19/94 Vector quantisation

Abstract

An image processing system including an image encoder and image decoding system is provided. The image encoder system includes an image decomposer, a block encoder, and an encoded image composer. The image decomposer decomposes the image into blocks. The block encoder which includes a selection module, a codeword generation module and a construction module, processes the blocks. Specifically, the selection module computes a set of parameters from image data values of a set of image elements in the image block. The codeword generation module generates codewords which the construction module uses to derive a set of quantized image data values. The construction module then maps each of the image element'"'"'s original image data values to an index to one of the derived image data values. The image decoding system reverses this process to reorder decompressed image blocks in an output data file.

Claims

1. An image encoder engine for encoding an image, comprising:

an image decomposer for decomposing the image into a header and at least one image block, each image block having a set of image elements and each image element having an original image data value;

at least one block encoder for receiving each image block and for compressing each image block into an encoded image block by associating each original image data value of the image element with an index to a derived image data value in a set of quantized image date values; and

an encoded image composer coupled to the block encoder for ordering the encoded image blocks into a data file.

2. The image encoder engine of claim 1 further comprising a header converter coupled to the image decomposer for converting the header into a modified header.

3. The image encoder engine of claim 2 wherein the encoded image composer orders the encoded image block and the modified header into a data file.

4. The image encoder engine of claim 1 wherein the block encoder further comprises a selection module for computing a set of parameters from the image data values of the set of image elements.

5. The image encoder engine of claim 1 wherein the block encoder further comprises a codeword generation module for generating at least one codeword.

6. The image encoder engine of claim 1 wherein the block encoder further comprises a construction module for generating the set of quantized image data values including at least one codeword and at least one derived image data value.

7. The image encoder engine of claim 1 wherein the block encoder further comprises a block type module for selecting an identifiable block type for the image block.

8. An image decoder engine for decoding an encoded image data file, comprising:

an encoded image decomposer for decomposing the encoded image data file into a modified header and at least one compressed image block, each image block having at least one associated codeword and a plurality of image elements associated with an index value;

at least one block decoder coupled to the encoded image decomposer for decompressing the at least one compressed image block into at least one decompressed image block by generating a set of quantized image data values and mapping the index value to a quantized image data value from the set of quantized image data values; and

an image composer for ordering the at least one decompressed image blocks in an output data file.

9. The image decoder engine of claim 8 wherein the set of quanitized image data values include the at least one codeword and at least one image data value derived from the at least one codeword.

10. The image decoder engine of claim 8 further comprising a header converter coupled to the encoded image decomposer for converting the modified header into an output header.

11. The image decoder engine of claim 10 wherein the image composer orders the at least one decompressed image block and the output header into a data file.

12. The image decoder engine of claim 8 wherein the at least one block decoder further comprises a block type detector for selecting a block type for each of the at least one compressed image block.

13. The image decoder engine of claim 8 wherein the at least one block decoder further comprises a decoder for decompressing each of the at least one compressed image block based on a block type.

14. The image decoder engine of claim 8 wherein the at least one block decoder further comprises an output selector for outputting the at least one decompressed image block.

15. A method for fixed-rate block-based image compression of an original image, comprising the steps of:

decomposing the original image into a header and a plurality of image blocks each having a set of image elements with an original image data value;

computing at least one codeword from the original image data value for the set of image elements;

generating a set of quantized image data values including the at least one codeword and at least one image value derived from the at least one codeword; and

mapping the original image data value to one of the quantized image data values to produce an index value for each image element.

16. The method of claim 15 further comprising outputting an encoded image data file.

17. The method of claim 15 further comprising the step of converting the header into a modified header.

18. The method of claim 17 further comprising the step of composing the modified header and encoded image blocks into the encoded image data file.

19. A machine readable medium having embodied thereon a program being executable by a machine to perform method steps for fixed-rate block-based image compression of an original image, the method steps comprising:

decomposing the original image into a header and a plurality of image blocks each having a set of image elements with an original image data value;

computing at least one codeword from the original image data value for the set of image elements;

generating a set of quantized image data values including the at least one codeword and at least one image value derived from the at least one codeword; and

mapping the original image data value to one of the quantized image data values to produce an index value for each image element.

20. The machine readable medium of claim 19 further comprising the method of outputting an encoded image data file.

21. An image encoder system for encoding an original image, comprising:

means for decomposing the original image into a header and a plurality of image blocks each having a set of image elements with an original image data value;

means for computing at least one codeword from the original image data value for the set of image elements;

means for generating a set of quantized image data values including the at least one codeword and at least one image value derived from the at least one codeword; and

means for mapping the original image data value to one of the quantized image data values to produce an index value for each image element.

22. The image encoder system of claim 21 further comprising means for outputting an encoded image data file.

23. A method for fixed-rate block-based image decompression of an encoded image, comprising the steps of:

decomposing the encoded image of into a modified header and a plurality of encoded image blocks having at least one codeword and a plurality of image elements associated with an index value;

generating a set of quanitized image data values including the at least one codeword and at least one image value derived from the at least one codeword; and

mapping the index value for each image element to one of the quantized image data values.

24. The method of claim 23 further comprising outputting a decoded image data file.

25. The method of claim 23 further comprising the step of converting the modified header into an output header.

26. The method of claim 25 further comprising the step of composing the output header and decoded image blocks into the decoded image data file.

27. A machine readable medium having embodied thereon a program being executable by a machine to perform method steps for fixed-rate block-based image decompression of an encoded image, the method steps comprising:

decomposing the encoded image data file into a modified header and a plurality of encoded image blocks having at least one codeword and a plurality of image elements associated with an index value;

generating a set of quanitized image data values including the at least one codeword and at least one image value derived from the at least one codeword; and

mapping the index value for each image element to one of the quantized image data values.

28. The machine readable medium of claim 27 further comprising the method of outputting a decoded image data file.

29. An image decoder engine for decoding an encoded image data file, comprising means for decomposing the encoded image data file into a modified header and a plurality of encoded image blocks having at least one codeword and a plurality of image elements associated with an index value;

means for generating a set of quanitized image data values including the at least one codeword and at least one image value derived from the at least one codeword; and

means for mapping the index value for each image element to one of the quantized image data values.

30. The image decoder engine of claim 29 further comprising means for outputting a decoded image data file.