System, method and article of manufacture for decompressing digital camera sensor data

• US 6,850,647 B1
• Filed: 07/26/2000
• Issued: 02/01/2005
• Est. Priority Date: 07/30/1999
• Status: Expired due to Fees

• Current Assignee: DBEZ Firenze LLC (SoftBank Group Corp.)
• Original Assignee: G&H Nevada-Tek
• Inventors: Gough, Michael L., Miner, Paul
• Primary Examiner(s): Mehta, Bhavesh M.
• Assistant Examiner(s): SUKHAPHADHANA, CHRISTOPHER T
• Application Number:
  US09/626,012
• Time in Patent Office: 1,651 Days
• Field of Search: 382/246, 382/233, 382/239, 341/67, 341/65, 341/106, 375/240.23, 348/231.1, 358/3.23, 358/426.13, 358/426.14
• US Class Current: 382/233
• 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: 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 19/156 Availability of hardware or computational resources, e.g. encoding based on power-saving criteria
• 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 19/42 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 19/436 using parallelised computational arrangements
• CPC Class Codes: H04N 19/44 Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder
• 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 19/60 using transform coding
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/91 Entropy coding, e.g. variable length coding [VLC] or arithmetic coding

Abstract

The present invention includes a system, method, and article of manufacture for decompressing a bit stream of compressed data representing a plurality of image blocks. This includes a two-step method of processing both a DC code and a plurality of AC codes. With respect to the processing of the AC codes, a plurality of bits of compressed input data relating to the AC codes are first retrieved from the bit stream. A first decoding operation is then executed based on the obtained compressed input data in order to generate first output data. It is then determined whether sufficient space is available for the first output data. If it is determined that there is sufficient space for the first output data, the first output data is outputted. On the other hand, if it is determined that there is insufficient space for the first output data, an alternate second decoding operation is executed in order to generate second output data. In order to carry out the foregoing decoding operations, a data structure is provided in a look-up table for being employed by the AC decoder during use. Such data structure includes a plurality of data segments each having a payload and a pointer. The payload includes a plurality of bits in one of a plurality of coding schemes. Further, the pointer corresponds to a routine which is capable of processing the coding scheme of the payload associated with the pointer. The first decoding operation first includes the step of performing a look-up in the look-up table based on the obtained compressed input data. The pointer is then retrieved from one of the data segments that corresponds to the obtained compressed input data. Next, the routine corresponding to the retrieved pointer is executed. The payload is then processed in the executed routine in order to generate the first output data. The foregoing routine that processes the payload of the data segment in order to generate the first output data may take many forms.

Claims

1. A method for decompressing a bit stream of compressed data representing a plurality of image portions, comprising:

obtaining a plurality of bits of compressed input data from a bit stream;

executing a first AC decoding operation based on the obtained plurality of bits of compressed input data in order to generate first output data as a recommendation;

emitting the first output data if it is determined that the recommendation should be accepted; and

executing a second AC decoding operation in order to generate second output data if it is determined the recommendation should not be accepted.

2. The method as set forth in claim 1, wherein the first decoding operation includes:

performing a look-up in a look-up table based on the obtained compressed input data, wherein the look-up table includes a plurality of data segments each having a payload including a plurality of bits in one of a plurality of coding schemes and a pointer corresponding to a routine which is capable of processing the coding scheme of the payload associated with the pointer;

retrieving the pointer from one of the data segments that corresponds to the obtained compressed input data;

executing the routine corresponding to the retrieved pointer; and

processing the payload in the executed routine in order to generate the first output data.

3. The method as set forth in claim 2, wherein the execution of the routine includes:

extracting data from the payload of the data segment;

formatting the extracted data;

outputting the formatted data; and

adding a number of coefficient components to a block position.

4. A method for decompressing a bit stream of compressed data representing a plurality of image portions, comprising:

obtaining a plurality of bits of compressed input data from a bit stream;

executing a first decoding operation based on the obtained compressed input data in order to generate first output data;

determining whether sufficient space is available for the first output data;

emitting the first output data if it is determined that there is sufficient space for the first output data; and

executing a second decoding operation in order to generate second output data if it is determined that there is insufficient space for the first output data;

wherein the second decoding operation includes;

performing a look-up in a look-up table based on the obtained compressed input data, wherein the look-up table includes a plurality of data segments each including the second output data therein;

zeroing out at least one bit of the compressed input data and performing another look-up if the look-up is unsuccessful;

retrieving the second output data from one of the data segments that corresponds to the obtained compressed input data; and

determining whether a current position is at an end of an image portion.

5. The method as set forth in claim 4, wherein upon being determined that the current position is not at the end of an image portion, the method further includes:

emitting zeros as specified by the second output data;

consuming a command component of the compressed input data;

retrieving a coefficient component of the compressed input data;

consuming the coefficient component of the compressed input data;

converting the coefficient component of the compressed input data to a signed integer;

emitting the coefficient component of the compressed input data if the coefficient component is of an appropriate size; and

determining whether a current position is at an end of an image portion.

6. The method as set forth in claim 5, wherein upon being determined that the current position is at the end of an image portion, the method further includes:

performing an inverse zigzag operation on the second output data;

merging an alternate buffer with a zigzag buffer;

performing an inverse quantization operation on the second output data;

performing an inverse DCT operation on the second output data; and

emitting the second output data.

7. The method as set forth in claim 4, wherein upon being determined that the current position is at the end of an image portion, the method further includes:

emitting zeros;

performing an inverse zigzag operation on the second output data;

merging an alternate buffer with a zigzag buffer;

performing an inverse quantization operation on the second output data;

performing an inverse DCT operation on the second output data; and

emitting the second output data.

8. A computer program embodied on a computer readable medium for decompressing a bit stream of compressed data representing a plurality of image portions, the computer program comprising:

a code segment for obtaining a plurality of bits of compressed input data from a bit stream;

a code segment for executing a first AC decoding operation based on the obtained plurality of bits of compressed input data in order to generate first output data as a recommendation;

a code segment for emitting the first output data if it is determined that the recommendation should be accepted; and

a code segment for executing a second AC decoding operation in order to generate second output data if it is determined that the recommendation should not be accepted.

9. The computer program as set forth in claim 8, wherein the first decoding operation is carried out by:

a code segment for performing a look-up in a look-up table based on the obtained compressed input data, wherein the look-up table includes a plurality of data segments each having a payload including a plurality of bits in one of a plurality of coding schemes and a pointer corresponding to a routine which is capable of processing the coding scheme of the payload associated with the pointer;

a code segment for retrieving the pointer from one of the data segments that corresponds to the obtained compressed input data;

a code segment for executing the routine corresponding to the retrieved pointer; and

a code segment for processing the payload in the executed routine in order to generate the first output data.

10. The computer program as set forth in claim 9, wherein the routine is carried out by:

a code segment for extracting data from the payload of the data segment;

a code segment for formatting the extracted data;

a code segment for outputting the formatted data; and

a code segment for adding a number of coefficient components to a block position.

11. A computer program embodied on a computer readable medium for decompressing a bit stream of compressed data representing a plurality of image portions, the computer program comprising:

a code segment for obtaining a plurality of bits of compressed input data from a bit stream;

a code segment for executing a first decoding operation based on the obtained compressed input data in order to generate first output data;

a code segment for determining whether sufficient space is available for the first output data;

a code segment for emitting the first output data if it is determined that there is sufficient space for the first output data; and

a code segment for executing a second decoding operation in order to generate second output data if it is determined that there is insufficient space for the first output data;

wherein the second decoding operation is carried out by;

a code segment for performing a look-up in a look-up table based on the obtained compressed input data, wherein the look-up table includes a plurality of data segments each including the second output data therein;

a code segment for zeroing out at least one bit of the compressed input data and performing another look-up if the look-up is unsuccessful;

a code segment for retrieving the second output data from one of the data segments that corresponds to the obtained compressed input data; and

a code segment for determining whether a current position is at an end of an image portion.

12. The computer program as set forth in claim 11, wherein upon being determined that the current position is not at the end of an image portion, the computer program further executes:

a code segment for emitting zeros as specified by the second output data;

a code segment for consuming a command component of the compressed input data;

a code segment for retrieving a coefficient component of the compressed input data;

a code segment for consuming the coefficient component of the compressed input data;

a code segment for converting the coefficient component of the compressed input data to a signed integer;

a code segment for emitting the coefficient component of the compressed input data if the coefficient component is of an appropriate size; and

a code segment for determining whether a current position is at an end of an image portion.

13. The computer program as set forth in claim 12, wherein upon being determined that the current position is at the end of an image portion, the computer program further executes:

a code segment for performing an inverse zigzag operation on the second output data;

a code segment for merging an alternate buffer with a zigzag buffer;

a code segment for performing an inverse quantization operation on the second output data;

a code segment for performing an inverse DCT operation on the second output data; and

a code segment for emitting the second output data.

14. The computer program as set forth in claim 11, wherein upon being determined that the current position is at the end of an image portion, the computer program further executes:

a code segment for emitting zeros;

a code segment for performing an inverse zigzag operation on the second output data;

a code segment for merging an alternate buffer with a zigzag buffer;

a code segment for performing an inverse quantization operation on the second output data;

a code segment for performing an inverse DCT operation on the second output data; and

a code segment for emitting the second output data.

15. A method for decompressing a bit stream of compressed data representing a plurality of image portions, comprising:

obtaining a plurality of bits of compressed input data from a bit stream;

performing a look-up in a look-up table based on the obtained compressed input data, wherein the look-up table includes a plurality of data segments each having a payload including a plurality of bits in one of a plurality of coding schemes and a pointer corresponding to a routine which is capable of precessing the coding scheme of the payload associated with the pointer;

retrieving the pointer from one of the data segments that corresponds to the obtained compressed input data;

executing the routine corresponding to the retrieved pointer, wherein the execution of the routine includes;

extracting a pointer from the data segment;

looking up an n-byte output;

emitting the n-byte output; and

adding the n-byte output to a block position; and

processing the payload in the executed routine in order to generate output data.

16. A method for decompressing a bit stream of compressed data representing a plurality of image portions, comprising:

obtaining a plurality of bits of compressed input data from a bit stream,

performing a look-up in a look-up table based on the obtained compressed input data, wherein the look-up table includes a plurality of data segments each having a payload including a plurality of bits in one of a plurality of coding schemes and a pointer corresponding to a routine which is capable of processing the coding scheme of the payload associated with the pointer;

retrieving the pointer from one of the data segments that corresponds to the obtained compressed input data;

executing the routine corresponding to the retrieved pointer; and

processing the payload in the executed routine in order to generate output data,

wherein the execution of the routine includes;

extracting two components of data from the payload of the data segment;

injecting a constant adjacent to the components of the data from the payload;

injecting a number of zeros between the components of the data from the payload; and

adding the components of the data from the payload, the constant, and the zeros to a block position.

17. The method as set forth in claim 16, wherein the constant is injected between the components.

18. The method as set forth in claim 16, wherein the constant is injected in front of the components.

19. The method as set forth in claim 16 wherein the constant is injected to the rear of the components.

20. A method for decompressing a bit stream of compressed data representing a plurality of image portions, comprising:

obtaining a plurality of bits of compressed input data from a bit stream;

performing a look-up in a look-up table based on the obtained compressed input data, wherein the look-up table includes a plurality of data segments each having a payload including a plurality of bits in one of a plurality of coding schemes and a pointer corresponding to a routine which is capable of processing the coding scheme of the payload associated with the pointer;

retrieving the pointer from one of the data segments that corresponds to the obtained compressed input data;

executing the routine corresponding to the retrieved pointer; and

processing the payload in the executed routine in order to generate output data,

wherein the execution of the routine includes;

extracting an auxiliary pointer from the payload of the data segment that corresponds to one of a plurality of auxiliary data segments in an auxiliary look-up table;

obtaining n bits; and

performing a look-up table jump.

21. A computer program embodied on a computer readable medium for decompressing a bit stream of compressed data representing a plurality of image portions, the computer program comprising:

a code segment for obtaining a plurality of bits of compressed input data from a bit stream;

a code segment for performing a look-up in a look-up table based on the obtained compressed input data, wherein the look-up table includes a plurality of data segments each having a payload including a plurality of bits in one of a plurality of coding schemes and a pointer corresponding to a routine which is capable of processing the coding scheme of the payload associated with the pointer;

a code segment for retrieving the pointer from one of the data segments that corresponds to the obtained compressed input data;

a code segment for executing the routine corresponding to the retrieved pointer,

wherein the routine is carried out by;

a code segment for extracting a pointer from the data segment;

a code segment for looking up an n-byte output;

a code segment for emitting the n-byte output; and

a code segment for adding the n-byte output to a block position; and

a code segment for processing the payload in the executed routine in order to generate the output data.

22. A computer program embodied on a computer readable medium for decompressing a bit stream of compressed data representing a plurality of image portions, the computer program comprising:

a code segment for obtaining a plurality of bits of compressed input data from a bit stream;

a code segment for performing a look-up in a look-up table based on the obtained compressed input data, wherein the look-up table includes a plurality of data segments each having a payload including a plurality of bits in one of a plurality of coding schemes and a pointer corresponding to a routine which is capable of processing the coding scheme of the payload associated with the pointer;

a code segment for retrieving the pointer from one of the data segments that corresponds to the obtained compressed input data;

a code segment for executing the routine corresponding to the retrieved pointer; and

a code segment for processing the payload in the executed routine in order to generate the output data, wherein the routine is carried out by;

a code segment for extracting two components of data from the payload of the data segment;

a code segment for injecting a constant adjacent to the components of the data from the payload;

a code segment for injecting a number of zeros between the components of the data from the payload; and

a code segment for adding the components of the data from the payload, the constant, and the zeros to a block position.

23. The computer program as set forth in claim 22 wherein the constant is injected between the components.

24. The computer program as set forth in claim 22, wherein the constant is injected in front of the components.

25. The computer program as set forth in claim 22 wherein the constant is injected to the rear of the components.

26. A computer program embodied on a computer readable medium for decompressing a bit stream of compressed data representing a plurality of image portions, the computer program comprising:

a code segment for obtaining a plurality of bits of compressed input data from a bit stream;

a code segment for performing a look-up in a look-up table based on the obtained compressed input data, wherein the look-up table includes a plurality of data segments each having a payload including a plurality of bits in one of a plurality of coding schemes and a pointer corresponding to a routine which is capable of processing the coding scheme of the payload associated with the pointer;

a code segment for retrieving the pointer from one of the data segments that corresponds to the obtained compressed input data;

a code segment for executing the routine corresponding to the retrieved pointer; and

a code segment for processing the payload in the executed routine in order to by generate the output data, wherein the routine is carried out by;

a code segment for extracting an auxiliary pointer from the payload of the data segment that corresponds to one of a plurality of auxiliary data segments in an auxiliary lookup table;

a code segment for obtaining n bits; and

a code segment for performing a look-up table jump.

27. A method for decompressing a bit stream of compressed data representing a plurality of image portions, comprising:

obtaining a plurality of bits of compressed input data from a bit stream;

performing a look-up in a look-up table based on the obtained compressed input data, wherein the look-up table includes a plurality of data segments each including output data therein;

zeroing out at least one bit of the compressed input data and performing another lookup if the look-up is unsuccessful;

retrieving the output data from one of the data segments that corresponds to the obtained compressed input data; and

determining whether a current position is at an end of an image portion.

28. The method as set forth in claim 27 wherein upon being determined that the current position is not at the end of an image portion, the method further includes:

emitting zeros as specified by the output data;

consuming a command component of the compressed input data;

retrieving a coefficient component of the compressed input data;

consuming the coefficient component of the compressed input data;

converting the coefficient component of the compressed input data to a signed integer;

emitting the coefficient component of the compressed input data if the coefficient component is of an appropriate size; and

determining whether a current position is at an end of an image portion.

29. The method as set forth in claim 27 wherein upon being determined that the current position is at the end of an image portion, the method further includes:

emitting zeros;

performing an inverse zigzag operation on the output data;

merging an alternate buffer with a zigzag buffer;

performing an inverse quantization operation on the output data;

performing an inverse DCT operation on the output data; and

emitting the output data.

30. The method as set forth in claim 27, wherein upon being determined that the current position is at the end of an image portion, the method further includes:

performing an inverse zigzag operation on the output data;

merging an alternate buffer with a zigzag buffer;

performing an inverse quantization operation on the output data;

performing an inverse DCT operation on the output data; and

emitting the output data.

31. A computer program embodied on a computer readable medium for decompressing a bit stream of compressed data representing a plurality of image portions, the computer program comprising:

a code segment for obtaining a plurality of bits of compressed input data from a bit stream;

a code segment for performing a look-up in a look-up table based on the obtained compressed input data, wherein the look-up table includes a plurality of data segments each including output data therein;

a code segment for zeroing out at least one bit of the compressed input data and performing another look-up if the look-up is unsuccessful;

a code segment for retrieving the output data from one of the data segments that corresponds to the obtained compressed input data; and

a code segment for determining whether a current position is at an end of an image portion.

32. The computer program as set forth in claim 31 wherein upon being determined that the current position is not at the end of an image portion, the computer program further executes:

a code segment for emitting zeros as specified by the output data;

a code segment for consuming a command component of the compressed input data;

a code segment for retrieving a coefficient component of the compressed input data;

a code segment for consuming the coefficient component of the compressed input data;

a code segment for converting the coefficient component of the compressed input data to a signed integer;

a code segment for emitting the coefficient component of the compressed input data if the coefficient component is of an appropriate size; and

a code segment for determining whether a current position is at an end of an image portion.

33. The computer program as set forth in claim 31, wherein upon being determined that the current position is at the end of an image portion, the computer program further executes:

a code segment for emitting zeros;

a code segment for performing an inverse zigzag operation on the output data;

a code segment for merging an alternate buffer with a zigzag buffer;

a code segment for performing an inverse quantization operation on the output data;

a code segment for performing an inverse DCT operation on the output data; and

a code segment for emitting the output data.

34. The computer program as set forth in claim 33 wherein upon being determined that the current position is at the end of an image portion, the computer program further executes:

a code segment for performing an inverse zigzag operation on the output data;

a code segment for merging an alternate buffer with a zigzag buffer;

a code segment for performing an inverse quantization operation on the output data;

a code segment for performing an inverse DCT operation on the output data; and

a code segment for emitting the output data.

35. A method for decompressing a bit stream of compressed data representing a plurality of image portions, comprising:

extracting a plurality of coefficient components from a bit stream;

executing an inverse quantization operation on at least some of the coefficient components;

executing an inverse DCT operation on at least some of the coefficient components; and

inserting zeros between the coefficient components after executing the inverse quantization operation and the inverse DCT operation.

36. The method as set forth in claim 35, wherein the inverse DCT operation is executed only on the coefficient components that are eligible.

37. A computer program embodied on a computer readable medium for decompressing a bit stream of compressed data representing a plurality of image portions, comprising:

a code segment for extracting a plurality of coefficient components from a bit stream;

a code segment for executing an inverse quantization operation on at least some of the coefficient components;

a code segment for executing an inverse DCT operation on at least some of the coefficient components; and

a code segment for inserting zeros between the coefficient components after executing the inverse quantization operation and the inverse DCT operation.

38. The computer program as set forth in claim 37 wherein the inverse DCT operation is executed only on the coefficient components that are eligible.