Region-based information compaction as for digital images

• US 6,118,820 A
• Filed: 03/30/1998
• Issued: 09/12/2000
• Est. Priority Date: 01/16/1998
• Status: Expired due to Term

• Current Assignee: DigiMedia Tech, LLC (IP Investments Group LLC)
• Original Assignee: Sarnoff Corporation (SRI International, Inc.)
• Inventors: Reitmeier, Glenn Arthur, Tinker, Michael
• Primary Examiner(s): LEE, RICHARD J
• Application Number:
  US09/050,304
• Time in Patent Office: 897 Days
• Field of Search: 348/390, 348/391, 348/396, 348/400-402, 348/405, 348/407, 348/409-413, 348/415, 348/416, 348/420, 348/421, 348/699, 382/232, 382/236, 382/238, 382/251
• US Class Current: 375/240.16
• CPC Class Codes: H04N 19/103 Selection of coding mode or of prediction mode
• CPC Class Codes: H04N 19/186 the unit being a colour or a chrominance component
• CPC Class Codes: H04N 19/20 using video object coding
• CPC Class Codes: H04N 19/30 using hierarchical techniques, e.g. scalability H04N19/63 takes precedence
• CPC Class Codes: H04N 19/98 Adaptive-dynamic-range coding [ADRC]

Abstract

A method and concomitant apparatus for preserving the dynamic range of a relatively high dynamic range information stream, illustratively a high resolution video signal, subjected to a relatively low dynamic range encoding and/or transport process(es). The invention subjects the relatively high dynamic range information stream to a segmentation and remapping process whereby each segment is remapped to the relatively low dynamic range appropriate to the encoding and/or transport process(es) utilized. An auxiliary information stream includes segment and associated remapping information such that the initial, relatively high dynamic range information stream may be recovered in a post-encoding (i.e. decoding) or post-transport (i.e., receiving) process.

Claims

1. A method for encoding an information stream comprising a plurality of information frames, each of said information frames comprising a plurality of information elements, each information element associated with at least one information element parameter, each information element parameter having a value between a lower limit and an upper limit, said upper and lower limits defining a dynamic range of said information element parameter, said method comprising the steps of:

defining, for each information frame, a plurality of information regions, each information region being associated with one or more respective information elements;

identifying, for each information region, a maximal value and a minimal value of at least one information element parameter associated with said information elements of said region;

remapping, for each information region, the at least one information element parameter of each information element of the region according to the identified maximal and minimal valve parameters associated with the respective region;

encoding each remapped information region to produce an encoded information stream; and

associating said identified maximal and minimal values with each remapped information region to produce a map identification stream, wherein said map identification stream includes information sufficient to substantially recover said identified maximal and minimal valve parameters associated with said remapped information element parameter for each information region.

2. The method of claim 1, wherein said information stream comprises a video information stream, said information element comprises a picture element, and said at least one information element parameter comprise one or more of a luminance parameter and a chrominance parameter.

3. The method of claim 2, wherein said encoding step comprises compression encoding each information frame of said information stream.

4. The method of claim 3 further comprising the step of transport encoding said encoded information stream and said associated map identification stream to form a transport stream for subsequent transmission to a receiver.

5. The method of claim 4, further comprising the steps of:

transport decoding and demultiplexing, at a receiver, said transport stream to recover said encoded information stream and said associated map identification stream;

compression decoding received encoded information stream to recover remapped information regions; and

inverse remapping, for each information region, each remapped information element parameter of each information element of the region according to the identified maximal and minimal level parameters associated with the respective region to recover said information stream.

6. The method of claim 3 wherein each information region is defined with respect to one of a picture, frame, field, slice, macroblock, block, pixel location, and motion vector.

7. The method of claim 1, wherein said step of remapping comprises one of a non-linear remapping step and a linear remapping step.

8. The method of claim 1, wherein said step of encoding reduces the dynamic range of at least one of said at least one information element parameter.

9. In an information processing system including an information processor that reduces a dynamic range of a relatively high dynamic range information element within an information stream processed therein, a method for substantially preserving the dynamic range of said relatively high dynamic range information element comprising the steps of:

segmenting said information stream into a plurality of information regions;

determining the value of each occurrence of said relatively high dynamic range information element within each of said plurality of information regions;

generating statistical indicia of a range of the value determined for each occurrence of said relatively high dynamic range information element within each of said plurality of information regions;

remapping, in accordance with the respective generated statistical indicia and the dynamic range of said information processor tending to reduce the dynamic range, the value of each occurrence of said relatively high dynamic range information element within each of said plurality of information regions to produce a remapped information stream;

processing, according to said information processor tending to reduce the dynamic range;

said remapped information stream to produce a dynamic range reduced information stream comprising a plurality of information regions including respective dynamic range reduced information elements;

inverse remapping, in accordance with respective generated statistical indicia, the value of each occurrence of said dynamic range reduced information elements within each of said information regions of said dynamic range reduced information stream, to produce a dynamic range restored information stream.

10. The method of claim 9, wherein said information processor comprises at least one of a compression encoding process and a transport multiplexing process.

11. The method of claim 10, wherein each information region is defined with respect to one of a picture, frame, field, slice, macroblock, block, pixel location, and motion vector.

12. The method of claim 9, wherein at least one of said remapping, processing and inverse remapping steps includes the step of imparting a transfer function characteristic to, respectively, remapped, processed and inverse remapped information.

13. The method of claim 12 wherein said transfer function characteristic comprises at least one of a gamma correction characteristic, a companding characteristic, a statistical redistribution characteristic, a simple linear characteristic, an arbitrary polynomial characteristic and a pre-determined function characteristic.

14. The method of claim 9, wherein said statistical indicia comprises at least one of a range measurement and a statistical distribution.

15. Apparatus for processing an information stream comprising a plurality of information frames, said apparatus comprising:

a regional map and scale unit, coupled to receive said information stream, for segmenting a received information frame into one or more information regions, and for remapping one or more relatively high dynamic range information parameters associated with each information region according to respective intra-region information parameter maxima and minima to produce a remapped information stream and an associated map region identification stream, said one or more remapped information parameters having a relatively low dynamic range, said map region identification stream includes information sufficient to substantially recover respective intra-region information parameter maxima and minima associated with said one or more relatively high dynamic range information parameters for each information region; and

a compression encoder, coupled to said regional map and scale unit, for compression encoding said remapped information stream to produce a compression encoded information stream.

16. The apparatus of claim 15, further comprising:

a transport encoder, coupled to said regional map and scale unit and said compression encoder, for transport encoding said compression encoded information stream and said map region identification stream to produce a transport stream.

17. The apparatus of claim 16, further comprising:

a transport decoder, coupled to receive said transport stream, for transport decoding said transport stream to recover said compression encoded information stream and said associated map region identification stream;

a compression decoder, coupled to said transport decoder, for compression decoding said compression encoded information stream from said transport decoder to recover said remapped information stream; and

an inverse regional map and scale unit, coupled to said compression decoder and said transport decoder, for inverse remapping said recovered remapped information stream according to said associated map region identification stream to substantially recover said information stream.

18. The apparatus of claim 16, wherein:

said information stream and comprises at least a video information stream;

said compression encoder comprises a compression encoder using intra-frame coding techniques and inter-frame coding techniques;

.

19. The apparatus of claim 15, wherein:

said regional map and scale unit imparts a transfer characteristic to said remapped information stream comprising at least one of a gamma correction characteristic, a companding characteristic, a statistical redistribution characteristic, a simple linear characteristic, an arbitrary polynomial characteristic and a pre-determined function characteristic.

20. The apparatus of claim 15, wherein each information region is defined with respect to one of a picture, frame, field, slice, macroblock, block, pixel location, and motion vector.