Method and apparatus for eliminating flicker by quantizing values based on previous quantization

• US 7,164,804 B2
• Filed: 03/15/2005
• Issued: 01/16/2007
• Est. Priority Date: 02/15/2001
• Status: Expired due to Fees

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Gormish, Michael J., Schwartz, Edward L., Boliek, Martin
• Primary Examiner(s): SHERALI, ISHRAT I
• Application Number:
  US11/081,281
• Publication Number:
  US 20050163388A1
• Time in Patent Office: 672 Days
• Field of Search: 382232-233, 382/248, 382250-251, 382/236, 382238-240, 382/268, 382274-275, 348/241, 348606-622, 375/240.03, 37524011-24016, 37524018-24021, 375/240.24
• US Class Current: 382/248
• CPC Class Codes: G11B 27/036 Insert-editing
• CPC Class Codes: H04N 19/10 using adaptive coding
• CPC Class Codes: H04N 19/115 Selection of the code volume for a coding unit prior to coding
• 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 19/124 Quantisation
• CPC Class Codes: H04N 19/126 Details of normalisation or weighting functions, e.g. normalisation matrices or variable uniform quantisers
• CPC Class Codes: H04N 19/129 Scanning of coding units, e.g. zig-zag scan of transform coefficients or flexible macroblock ordering [FMO]
• CPC Class Codes: H04N 19/146 Data rate or code amount at the encoder output
• CPC Class Codes: H04N 19/147 according to rate distortion criteria rate-distortion as a criterion for motion estimation H04N19/567
• CPC Class Codes: H04N 19/152 by measuring the fullness of the transmission buffer
• CPC Class Codes: H04N 19/154 Measured or subjectively estimated visual quality after decoding, e.g. measurement of distortion use of rate-distortion criteria H04N19/147
• CPC Class Codes: H04N 19/162 User input
• CPC Class Codes: H04N 19/17 the unit being an image region, e.g. an object
• CPC Class Codes: H04N 19/172 the region being a picture, frame or field
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/34 Scalability techniques involving progressive bit-plane based encoding of the enhancement layer, e.g. fine granular scalability [FGS]
• CPC Class Codes: H04N 19/36 Scalability techniques involving formatting the layers as a function of picture distortion after decoding, e.g. signal-to-noise [SNR] scalability
• CPC Class Codes: H04N 19/40 using video transcoding, i.e. partial or full decoding of a coded input stream followed by re-encoding of the decoded output stream
• 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 19/423 characterised by memory arrangements H04N19/433 takes precedence
• CPC Class Codes: H04N 19/426 : using memory downsizing methods
• CPC Class Codes: H04N 19/45 : performing compensation of the inverse transform mismatch, e.g. Inverse Discrete Cosine Transform [IDCT] mismatch
• 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 19/593 : involving spatial prediction techniques
• CPC Class Codes: H04N 19/61 : in combination with predictive coding
• CPC Class Codes: H04N 19/619 : the transform being operated outside the prediction loop
• CPC Class Codes: H04N 19/63 : using sub-band based transform, e.g. wavelets
• CPC Class Codes: H04N 19/635 : characterised by filter definition or implementation details
• CPC Class Codes: H04N 19/64 : characterised by ordering of coefficients or of bits for transmission
• CPC Class Codes: H04N 19/645 : by grouping of coefficients into blocks after the transform
• CPC Class Codes: H04N 19/647 : using significance based coding, e.g. Embedded Zerotrees of Wavelets [EZW] or Set Partitioning in Hierarchical Trees [SPIHT]
• CPC Class Codes: H04N 19/70 : characterised by syntax aspects related to video coding, e.g. related to compression standards
• CPC Class Codes: H04N 19/85 : using pre-processing or post-processing specially adapted for video compression
• CPC Class Codes: H04N 19/86 : involving reduction of coding artifacts, e.g. of blockiness

Abstract

A method and apparatus for eliminating flicker by quantizing values based on previous quantization is described. In one embodiment, the method comprises encoding a first coefficient value in a first frame of a motion sequence and subsequently setting a second coefficient in a second frame of the motion sequence and in the same position as the first coefficient to be within a predetermined closeness with the value of the first coefficient.

Claims

1. A computer implemented method comprising:

encoding a first coefficient value in a first region of a first frame of a motion sequence;

determining difference between the first coefficient and a second coefficient of a second region of a second frame corresponding to the first region of the motion sequence; and

modifying the second coefficient to be within a predetermined closeness with the value of the first coefficient;

wherein the second coefficient is modified based on a relationship between the first and second coefficients with respect to a predetermined threshold; and

wherein the predetermined threshold varies based on a subband in which at least one of the first and second regions locates.

2. The method of claim 1, wherein the second frame is a subsequent frame with respect to the first frame of the motion sequence.

3. The method of claim 1, wherein the first and second frames are successive frames of the motion sequence.

4. The method of claim 1, wherein the second coefficient is modified to be substantially identical to the first coefficient.

5. The method of claim 1, wherein the second coefficient is modified if the difference between the first and second coefficients satisfies one or more criteria.

6. The method of claim 1, wherein the second coefficient is modified if the difference between the first and second coefficients satisfies a predetermined threshold.

7. The method of claim 1, wherein the second coefficient is modified based on quantization of the first frame which produces the first coefficient.

8. The method of claim 1, further comprising setting at least a portion of remaining regions other than the second region of the second frame with coefficient values different than a corresponding portion of the first frame.

9. A computer-readable medium having instructions, which when executed by a computer, cause the computer to perform a method, the method comprising:

encoding a first coefficient value in a first region of a first frame of a motion sequence;

determining difference between the first coefficient and a second coefficient of a second region of a second frame corresponding to the first region of the motion sequence;

modifying the second coefficient to be within a predetermined closeness with the value of the first coefficient wherein the second coefficient is modified based on a relationship between the first and second coefficients with respect to a predetermined threshold; and

wherein the predetermined threshold varies based on a subband in which at least one of the first and second regions locates.

10. The computer-readable medium of claim 9, wherein the second frame is a subsequent frame with respect to the first frame of the motion sequence.

11. The computer-readable medium of claim 9, wherein the first and second frames are successive frames of the motion sequence.

12. The computer-readable medium of claim 9, wherein the second coefficient is modified to be substantially identical to the first coefficient.

13. The computer-readable medium of claim 9, wherein the second coefficient is modified if the difference between the first and second coefficients sad satisfies one or more criteria.

14. The computer-readable medium of claim 9, wherein the second coefficient is modified if the difference between the first and second coefficients satisfies a predetermined threshold.

15. The computer-readable medium of claim 9, wherein the second coefficient is modified based on quantization of the first frame which produces the first coefficient.

16. The computer-readable medium of claim 9, wherein the method further comprises setting at least a portion of remaining regions other than the second region of the second frame with coefficient values different than a corresponding portion of the first frame.

17. An apparatus, comprising:

means for encoding a first coefficient value in a first region of a first frame of a motion sequence;

means for determining difference between the first coefficient and a second coefficient of a second region of a second frame corresponding to the first region of the motion sequence;

wherein the second coefficient is modified based on a relationship between the first and second coefficients with respect to a predetermined threshold; and

wherein the predetermined threshold varies based on a subband in which at least one of the first and second regions locates

means for modifying the second coefficient to be within a predetermined closeness with the value of the first coefficient.