Enhanced transform compatibility for standardized data compression

• US 6,393,156 B1
• Filed: 01/06/1999
• Issued: 05/21/2002
• Est. Priority Date: 01/07/1998
• Status: Expired due to Fees

• Current Assignee: Joel A. Rosiene, Truong Q. Nguyen
• Original Assignee: Joel A. Rosiene, Truong Q. Nguyen
• Inventors: Nguyen, Truong Q., Rosiene, Joel A.
• Primary Examiner(s): Mehta, Bhavesh
• Assistant Examiner(s): Bayat, Ali
• Application Number:
  US09/226,586
• Time in Patent Office: 1,231 Days
• Field of Search: 382/248, 382/249, 382/250, 358/432, 358/433, 375/240.26
• US Class Current: 382/248
• CPC Class Codes: G06T 9/007 Transform coding, e.g. discrete cosine transform

Abstract

In an apparatus and method for image/video enhancement, pre-processing and post-processing techniques are employed to effectively modify the transforms used in a fixed, standardized data compression coder. In this manner, alternative transforms, for example overlapping-basis-type transforms, are made to be applicable to, and compatible with, various data compression standards, thereby improving system performance.

Claims

1. In a data compression system employing a fixed transform, a method for pre-processing input data comprising:

modifying the input data by a cancellation transform which is the substantial inverse of the fixed transform to generate pre-processed data; and

applying the pre-processed data to the fixed transform to generate compressed data;

the compressed data being substantially unaffected by the fixed transform of the data compression system.

2. The method of claim 1 further comprising modifying the input data by an alternative transform.

3. The method of claim 2 wherein the alternative transform comprises a transform selected from the group consisting of:

Lapped Orthogonal Transform, Generalized Lapped Orthogonal Transform, Wavelet Transform, Wavelet-Packed Transform, and artifact-reduction transform.

4. The method of claim 1 further comprising decompressing the compressed data by applying the compressed data to a decompression transform which is the substantial inverse of the fixed transform.

5. The method of claim 4 further comprising applying the decompressed data to the fixed transform, to generate output data which is substantially unaffected by the fixed transform.

6. The method of claim 5 further comprising post-processing the output data by applying the output data to a substantial inverse of the alternative transform to generate post-processed data.

7. The method of claim 1 wherein the fixed transform comprises a Discrete Cosine-based transform (DCT).

8. The method of claim 1 wherein the input data and output data comprise signals selected from the following set of signals:

image data, video data, audio data, and multidimensional data.

9. The method of claim 8 wherein pre-processing is applied to all rows and columns of multidimensional data.

10. The method of claim 1 wherein the fixed transform is fixed in a standardized compression system selected from the following group of systems:

JPEG, MPEG-I, MPEG-II, H.261, H.263, H.263+, and H.324.

11. The method of claim 1 wherein pre-processing is applied to all images of a video sequence, or a subset thereof.

12. The method of claim 1 wherein the data compression system is of a type selected from the group of system types comprising floating point, fixed point, and integer-valued.

13. The method of claim 1 further comprising intensity-scaling the pre-processed data to match the dynamic range of the data compression system.

14. A method for modifying source data with an alternative transform in a data compression system employing a fixed transform compliant with predetermined data compression standards comprising:

modifying the source data with an alternative transform to generate input data;

modifying the input data with a cancellation transform which is the substantial inverse of the fixed transform to generate pre-processed data; and

applying the pre-processed data to the fixed transform to generate compressed data;

the compressed data being substantially unaffected by the fixed transform.

15. The method of claim 14 further comprising decompressing the compressed data by applying the compressed data to a decompression transform which is the substantial inverse of the fixed transform.

16. The method of claim 15 further comprising applying the decompressed data to the fixed transform, to generate output data which is substantially unaffected by the fixed transform.

17. The method of claim 16 further comprising post-processing the output data by applying the output data to a substantial inverse of the alternative transform to generate post-processed data.

18. In a data compression system employing an inverse of a fixed transform, a method for post-processing compressed data comprising:

applying the compressed data to the inverse of the fixed transform to generate decompressed data;

applying the decompressed data to a cancellation transform which is substantially the inverse of the fixed transform to generate post-processed data;

the post-processed data being substantially unaffected by the inverse of the fixed transform of the data compression system.

19. The method of claim 18 further comprising modifying the post-processed data by an inverse of an alternative transform to generate output data.

20. The method of claim 19 wherein the alternative transform comprises a transform selected from the group consisting of:

Lapped Orthogonal Transform, Generalized Lapped Orthogonal Transform, Wavelet Transform, Wavelet-Packed Transform, and artifact-reduction transform.

21. The method of claim 18 further comprising pre-processing input data to generate the compressed data by:

modifying the input data by the inverse of the fixed transform to generate pre-processed data; and

applying the pre-processed data to the cancellation transform to generate compressed data.

22. The method of claim 21 further comprising modifying the input data by the alternative transform.

23. The method of claim 18 wherein the fixed transform comprises a Discrete Cosine-based transform (DCT).

24. The method of claim 18 wherein the input data and output data comprise signals selected from the following set of signals:

image data, video data, audio data, and multidimensional data.

25. The method of claim 24 wherein pre-processing is applied to all rows and columns of multidimensional data.

26. The method of claim 18 wherein the fixed transform is fixed in a standardized compression system selected from the following group of systems:

JPEG, MPEG-I, MPEG-II, H.261, H.263, H.263+, and H.324.

27. A system for pre-processing input data by an alternative transform to generate compressed data in a data compression system employing a fixed transform comprising:

an alternative transform for modifying the input data to generate alternative data;

a first cancellation transform for modifying the alternative data by a first cancellation transform which is the substantial inverse of the fixed transform to generate pre-processed data; and

a data compressor including a fixed transform for processing the pre-processed data to generate compressed data;

the compressed data being substantially unaffected by the fixed transform of the data compression system.

28. The system of claim 27 wherein the alternative transform comprises a transform selected from the group consisting of:

Lapped Orthogonal Transform, Generalized Lapped Orthogonal Transform, Wavelet Transform, Wavelet-Packed Transform, and artifact-reduction transform.

29. The system of claim 27 further comprising a decompression transform which is the substantial inverse of the fixed transform for decompressing the compressed data.

30. The system of claim 29 further comprising a second cancellation transform substantially comprising the fixed transform for processing the decompressed data to generate output data which is substantially unaffected by the fixed transform.

31. The system of claim 30 further comprising a post-processor for applying the output data to a substantial inverse of the alternative transform to generate post-processed data.

32. The system of claim 27 wherein the fixed transform comprises a Discrete Cosine-based transform (DCT).

33. A system for post-processing compressed data in a data decompression system employing an inverse of a fixed transform comprising:

a fixed data decompressor for applying the compressed data to the inverse of the fixed transform to generate decompressed data;

a first cancellation transform which is substantially the fixed transform to generate post-processed data;

the post-processed data being substantially unaffected by the inverse of the fixed transform of the data compression system; and

an inverse alternative transform for modifying the post-processed data by an inverse of an alternative transform to generate output data.

34. The system of claim 33 wherein the alternative transform comprises a transform selected from the group consisting of:

Lapped Orthogonal Transform, Generalized Lapped Orthogonal Transform, Wavelet Transform, Wavelet-Packed Transform, and artifact-reduction transform.

35. The system of claim 33 further comprising a preprocessor for pre-processing input data by an alternative transform to generate compressed data in a data compression system employing a fixed transform comprising:

an alternative transform for modifying the input data to generate alternative data;

a second cancellation transform for modifying the alternative data by a second cancellation transform which is the substantial inverse of the fixed transform to generate pre-processed data; and

a data compressor including a fixed transform for processing the pre-processed data to generate compressed data;

the compressed data being substantially unaffected by the fixed transform of the data compression system.

36. The system of claim 33 wherein the fixed transform comprises a Discrete Cosine-based transform (DCT).