Methods and Systems for Filter Characterization

• US 20070160134A1
• Filed: 09/27/2006
• Published: 07/12/2007
• Est. Priority Date: 01/10/2006
• Status: Abandoned Application

• Current Assignee: Sharp Laboratories of America Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Laboratories of America Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Segall, Christopher A.
• Application Number:
  US11/535,800
• Publication Number:
  US 20070160134A1
• Time in Patent Office: Days
• US Class Current: 375/240.100
• CPC Class Codes: H04N 19/117 Filters, e.g. for pre-processing or post-processing sub-band filter banks H04N19/635
• CPC Class Codes: H04N 19/136 Incoming video signal characteristics or properties
• CPC Class Codes: H04N 19/33 in the spatial domain
• 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 19/59 involving spatial sub-sampling or interpolation, e.g. alteration of picture size or resolution
• CPC Class Codes: H04N 19/80 Details of filtering operations specially adapted for video compression, e.g. for pixel interpolation H04N19/635, H04N19/86 take precedence

Abstract

Embodiments of the present invention comprise methods and systems for down-sampling and up-sampling an image. Some embodiments comprise methods and systems for sampling images for spatial scalability.

Claims

1. A method for signaling a filter selection from an encoder to a decoder, said method comprising:

a) storing a plurality of filter definitions at an encoder and a decoder;

b) determining filter characteristics for a sampling task;

c) selecting a weighted combination of filters defined in said filter definitions, wherein said weighted combination meets said filter characteristics; and

d) transmitting filter weighting factors from said encoder to said decoder, wherein said weighting factors communicate said weighted combination.

2. A method as described in claim 1 wherein said filter definitions comprise tap values for a family of filters.

3. A method as described in claim 1 wherein said determining filter characteristics comprises analysis of input image characteristics.

4. A method as described in claim 1 wherein said sampling task comprises up-sampling and said determining filter characteristics comprises analysis of the down-sampling process and down-sampling filter data.

5. A method as described in claim 1 wherein said determining filter characteristics comprises a rate/distortion analysis.

6. A method as described in claim 1 wherein said filtering task comprises re-sampling and said determining filter characteristics comprises analysis of a reconstructed base layer image.

7. A method as described in claim 1 wherein said selecting a weighted combination of filters comprises evaluation of error rates for various combinations of weighting factors.

8. A method for selecting and signaling an up-sampling filter selection from an encoder to a decoder, said method comprising:

a) storing a plurality of up-sampling filter definitions at an encoder and a decoder;

b) determining down-sampling filter characteristics;

c) selecting a weighted combination of filters that are defined in said filter definitions, wherein said weighted combination defines an up-sampling filter; and

d) transmitting filter weighting factors from said encoder to said decoder, wherein said weighting factors communicate said weighted combination.

9. A method as described in claim 8 wherein said plurality of up-sampling filter definitions comprise definitions for filters with varying quantities of tap values.

10. A method as described in claim 8 wherein said up-sampling filter definitions comprise definitions for filters with multiple phases.

11. A method for filtering an image at a decoder, said method comprising:

a) storing a plurality of filter definitions at a decoder;

b) receiving an image;

c) receiving filter weighting factors at said decoder, wherein said weighting factors communicate a weighted combination of filters defined in said filter definitions; and

d) filtering said image using said weighted combination of filters.

12. A method as described in claim 11 wherein said plurality of filter definitions comprise definitions for filters with varying quantities of tap values.

13. A method as described in claim 11 wherein said filter definitions comprise definitions for filters with multiple phases.

14. A method as described in claim 11 wherein said filter definitions comprise tap values for a family of filters.

15. A method as described in claim 11 wherein said weighting factors have been determined using methods comprising image analysis of said image.

16. A method as described in claim 11 wherein said weighting factors have been determined using methods comprising analysis of the down-sampling operator and down-sampling filter data.

17. A method as described in claim 11 wherein said weighting factors have been determined using methods comprising a rate/distortion analysis.

18. A method as described in claim 11 wherein said weighting factors have been determined using methods comprising analysis of a reconstructed base layer frame.

19. A method as described in claim 11 wherein said weighting factors have been determined using methods comprising evaluation of error rates for various combinations of weighting factors.

20. A method as described in claim 11 wherein said image is a base layer image that has been down-sampled from a higher resolution image and said weighting factors have been determined using methods comprising analysis of a down-sampling filter used to create said base layer.