Selection of the maximum dynamic range of transformed data and the data precision of transform matrices according to the bit depth of input data

Patent metadata

Field	Value
Publication number	US-2016353109-A1
Application number	US-201414778445-A
Country	US
Kind code	A1
Filing date	Apr 4, 2014
Priority date	Apr 8, 2013
Publication date	Dec 1, 2016
Grant date	—

Abstract

A method of encoding image data, including: frequency-transforming input image data to generate an array of frequency-transformed input image coefficients by a matrix-multiplication process, according to a maximum dynamic range of the transformed data and using transform matrices having a data precision; and selecting the maximum dynamic range and/or the data precision of the transform matrices according to the bit depth of the input image data.

First claim

1 - 43 . (canceled)

44 . A method of encoding image data, comprising:
frequency-transforming input image data to generate an array of frequency-transformed input image coefficients by a matrix-multiplication process, according to a maximum dynamic range of the transformed data and using transform matrices having a data precision; and selecting the maximum dynamic range and/or the data precision of the transform matrices according to the bit depth of the input image data.

45 . The method according to claim 44 , in which the selecting comprises:
setting the data precision of the transform matrices to a first offset number of bits less than the bit depth of the input image data; and setting the maximum dynamic range of the transformed data to a second offset number of bits greater than the bit depth of the input image data.

46 . The method according to claim 45 , wherein the first offset number of bits is equal to 2 and the second offset number of bits is equal to 6.

47 . The method according to claim 44 , further comprising:
deriving transform matrices at a required data precision from respective source transform matrices at a different data precision.

48 . A method of decoding image data, comprising:
frequency-transforming input frequency-transformed image data to generate an array of output image data by a matrix-multiplication process, according to a maximum dynamic range of the transformed data and using transform matrices having a data precision; and selecting the maximum dynamic range and/or the data precision of the transform matrices according to the bit depth of the output image data.

49 . The method according to claim 48 , wherein the selecting comprises:
setting the data precision of the transform matrices to a first offset number of bits less than the bit depth of the output image data; and setting the maximum dynamic range of the transformed data to a second offset number of bits greater than the bit depth of the output image data.

50 . The method according to claim 49 , wherein the first offset number of bits is equal to 2 and the second offset number of bits is equal to 6.

51 . The method according to claim 48 , further comprising:
deriving transform matrices at a required data precision from respective source transform matrices at a different data precision.

52 . A data encoding apparatus for encoding image data, the apparatus comprising:
a frequency transformer configured to frequency-transform input image data to generate an array of frequency-transformed input image coefficients by a matrix-multiplication process, according to a maximum dynamic range of the transformed data and using transform matrices having a data precision; and selector circuitry configured to select the maximum dynamic range and/or the data precision of the transform matrices according to the bit depth of the input image data.

53 . The data encoding apparatus according to claim 52 , wherein the selector circuitry is configured to:
set the data precision of the transform matrices to a first offset number of bits less than the bit depth of the input image data; and set the maximum dynamic range of the transformed data to a second offset number of bits greater than the bit depth of the input image data.

54 . The data encoding apparatus to claim 53 , wherein the first offset number of bits is equal to 2 and the second offset number of bits is equal to 6.

55 . The data encoding apparatus to claim 52 , further comprising a processor configured to:
derive transform matrices at a required data precision from respective source transform matrices at a different data precision.

56 . Image data decoding apparatus comprising:
a frequency transformed configured to frequency-transform input frequency-transformed image data to generate an array of output image data by a matrix-multiplication process, according to a maximum dynamic range of the transformed data and using transform matrices having a data precision; and selector circuitry configured to select the maximum dynamic range and/or the data precision of the transform matrices according to the bit depth of the output image data.

57 . The data decoding apparatus according to claim 56 , wherein the selector circuitry is configured to:
set the data precision of the transform matrices to a first offset number of bits less than the bit depth of the output image data; and set the maximum dynamic range of the transformed data to a second offset number of bits greater than the bit depth of the output image data.

58 . The data decoding apparatus to claim 57 , wherein the first offset number of bits is equal to 2 and the second offset number of bits is equal to 6.

59 . The data encoding apparatus to claim 56 , further comprising a processor configured to:
derive transform matrices at a required data precision from respective source transform matrices at a different data precision.

60 . A video data capture, transmission, display and/or storage apparatus comprising an apparatus according to claim 52 .

61 . A non-transitory computer readable medium including computer program instructions, which when executed by a computer causes the computer to perform the method of claim 48 .

Assignees

• Sony Corp

Inventors

• Berry David
• Gamei James Alexander
• Saunders Nicholas Ian
• Sharman Karl James

Classifications

• H03M7/40

  Conversion to or from variable length codes, e.g. Shannon-Fano code, Huffman code, Morse code · CPC title

• H04N19/136

  Incoming video signal characteristics or properties · CPC title

• H04N19/93

  Run-length coding · CPC title

• H04N19/44

  Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder · CPC title

• H03M7/3068

  Precoding preceding compression, e.g. Burrows-Wheeler transformation · CPC title