Picture element processor for a memory management system

• US 5,844,608 A
• Filed: 12/12/1996
• Issued: 12/01/1998
• Est. Priority Date: 12/12/1996
• Status: Expired due to Term

• Current Assignee: Thomson Licensing Dtv
• Original Assignee: Thomson Consumer Electronics Incorporated (Vantiva SA)
• Inventors: Yu, Haoping, Kranawetter, Greg Alan, Lam, Wai-man
• Primary Examiner(s): BRITTON, HOWARD W
• Application Number:
  US08/764,454
• Time in Patent Office: 719 Days
• Field of Search: 348/390, 348/409, 348/416, 348/420, 348/421, 348/845
• US Class Current: 375/240.01
• 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 19/423 characterised by memory arrangements H04N19/433 takes precedence
• CPC Class Codes: H04N 19/428 Recompression, e.g. by spatial or temporal decimation
• 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 19/91 Entropy coding, e.g. variable length coding [VLC] or arithmetic coding

Abstract

A television receiver includes an MPEG decoder for providing decoded pixel blocks. Decoded pixels are recompressed prior to storage in frame memory. In the recompression process a reference first pixel is compressed as a function of a pixel block parameter. A reconstructed reference pixel value is used in a prediction network when reconstructing remaining pixels of the pixel block prior to display. A first pixel processor accurately compresses a reference pixel which prevents the propagation of a prediction error throughout the reconstructed block.

Claims

1. A system for processing a data stream of compressed image representative pixel data blocks comprising:

a first decompressor (62,

     64) for decompressing said pixel blocks to produce decompressed data;

a compressor (12) for recompressing said decompressed data into recompressed data as a function of a predetermined pixel block parameter; and

a memory (14) for storing said recompressed data.

2. A system according to claim 1, wherein:

said block parameter is selected from at least one of the parameters including the minimum pixel value, the maximum pixel value, a reference pixel value, a range of pixel values, the mean block pixel value, and the median block pixel value.

3. A system according to claim 2, wherein:

said compressor (12) and said second decompressor (16) exhibit mutually inverse operating characteristics.

4. A system according to claim 1, further comprising:

a second decompressor (16) for decompressing recompressed data from said memory as a function of said block parameter; and

an output network (54,

     56) including a display processor (54) for processing data decompressed by said second decompressor (16).

5. A system according to claim 4, further comprising:

a third decompressor (50) for decompressing said recompressed data; and

a motion compensation system (70) for providing motion compensated data in response to decompressed data from said third decompressor.

6. A system according to claim 1, wherein:

said compressor recompresses a reference pixel of a data block as a function of said block parameter, and wherein

said system further includes a pixel prediction network (18) responsive to said reference pixel to facilitate predictive processing of other pixels of said pixel block.

7. A system according to claim 6, wherein:

said block parameter is the minimum pixel value.

8. A system according to claim 6, wherein:

said compressor (12) and said second decompressor (16) exhibit mutually inverse operating characteristics.

9. In a system for processing a data stream of image information including MPEG compressed pixel blocks constituting an image frame, said pixel blocks each having a block parameter, a processor comprising:

a first decompressor (62,

     64) for decompressing said data stream into decompressed pixel block data;

a compression network (12) for recompressing said decompressed pixel data into recompressed data as a function of said block parameter;

a pixel prediction network (18) responsive to a reference pixel to facilitate predictive processing of other pixels of said data block; and

a frame memory (14) for storing said recompressed data.

10. A system according to claim 9, wherein:

said block parameter is the minimum pixel value.

11. A system according to claim 9, said compression network (12) further comprising:

a first data reduction network (30) for processing said reference pixel; and

a second data reduction network (28) for processing other pixels of the pixel block.

12. A system according to claim 11, wherein:

said block parameter is selected from at least one of the parameters including the minimum pixel value, the maximum pixel value, a reference pixel value, a range of pixel values, the mean block pixel value, and the median block pixel value.

13. A system according to claim 11, wherein:

said first data reduction network (30) and said second data reduction network (28) are quantizers.

14. A system according to claim 13, wherein:

said compressor (12) and said second decompressor (16) exhibit mutually inverse operating characteristics.

15. A system according to claim 9, further comprising:

a second decompressor (16) for decompressing recompressed data from said frame memory (14) as a function of said block parameter; and

an output network (54,

     56) including a display processor (54) for processing data decompressed by said second decompressor (16).

16. A system according to claim 15, further comprising:

a third decompressor (50) for decompressing said recompressed data; and

a motion compensation system (70) for providing motion compensated data in response to decompressed data from said third decompressor.

17. A system according to claim 15, wherein:

said second decompressor (16) decompresses a reference pixel of a data block as a function of said block parameter, and wherein said system further includes

a second pixel prediction network (24) responsive to said reference pixel to facilitate predictive processing of other pixels of said data block during decompression.

18. A system according to claim 17, said second decompressor (16) further comprising:

a first data reconstruction network (38) for processing said reference pixel; and

a second data reconstruction network (36) for processing other pixels of the pixel block.