Simplification of local contrast compensation by using weighted look-up table

Patent metadata

Field	Value
Publication number	US-9245495-B2
Application number	US-201214129242-A
Country	US
Kind code	B2
Filing date	Dec 21, 2012
Priority date	Dec 29, 2011
Publication date	Jan 26, 2016
Grant date	Jan 26, 2016

Abstract

Systems, apparatus, articles, and methods are described including operations to generate a weighted look-up-table based at least in part on individual pixel input values within an active block region and on a plurality of contrast compensation functions. A second level compensation may be performed for a center pixel block of the active region based at least in part on the weighted look-up-table.

First claim

What is claimed:

1. A computer-implemented method, comprising:
associating a plurality of contrast compensation functions with a plurality of individual pixel blocks within an active block region portion of an image, wherein individual pixel bocks include one or more pixels associated with a one or more corresponding pixel input values;

generating a weighted look-up-table based at least in part on the individual pixel input values within the active block region and on the plurality of contrast compensation functions;
performing a second level compensation for a center pixel block of the active region based at least in part on the weighted look-up-table; and
determining a first one dimensional interpolation based at least in part on the weighted look-up-table, wherein the first one dimensional interpolation is associated with a first dimension of the image, wherein the first one dimensional interpolation is based at least in part on a first portion associated with a first half of a four corner coordinates and a second portion associated with a second half of the four corner coordinates;
wherein generating the weighted look-up-table further comprises determining intermediate pixel values associated with four non-center corner coordinates for individual pixel input values on a pixel block by pixel block basis, wherein the intermediate pixel values associated with the four corner coordinates are stored in the weighted look-up-table.

2. The method of claim 1 , wherein the plurality of contrast compensation functions comprises a piecewise linear function-type contrast compensation function.

3. The method of claim 1 , wherein the plurality of contrast compensation functions comprises a look-up-table-type contrast compensation function.

4. The method of claim 1 , wherein the intermediate pixel values are determined based a least in part on weighting of a position of the four corner coordinates and on the plurality of contrast compensation functions.

5. The method of claim 1 , wherein performing the second level compensation for the center pixel block of the active region further comprises:
determining a first one dimensional interpolation based at least in part on the weighted look-up-table, wherein the first one dimensional interpolation is associated with a first dimension of the image; and
determining an output pixel value for the center pixel block of the active region via a second one dimensional interpolation based at least in part on the determined first one dimensional interpolation, wherein the second one dimensional interpolation is associated with a second dimension of the image.

6. The method of claim 1 , wherein performing the second level compensation for the center pixel block of the active region further comprises:
determining a first one dimensional interpolation based at least in part on the weighted look-up-table, wherein the first one dimensional interpolation is associated with a first dimension of the image, wherein the first one dimensional interpolation is based at least in part on a first portion associated with a first half of the four corner coordinates and a second portion associated with a second half of the four corner coordinates; and
determining an output pixel value for the center pixel block of the active region via a second one dimensional interpolation based at least in part on the determined first one dimensional interpolation, wherein the second one dimensional interpolation is associated with a second dimension of the image.

7. The method of claim 1 , wherein the plurality of contrast compensation functions comprises a piecewise linear function-type contrast compensation function or a look-up-table-type contrast compensation function,
wherein generating the weighted look-up-table further comprises:
wherein the intermediate pixel values are determined based a least in part on weighting of a position of the four corner coordinates and on the plurality of contrast compensation functions,

wherein performing the second level compensation for the center pixel block of the active region further comprises:
determining a first one dimensional interpolation based at least in part on the weighted look-up-table, wherein the first one dimensional interpolation is associated with a first dimension of the image, wherein the first one dimensional interpolation is based at least in part on a first portion associated with a first half of the four corner coordinates and a second portion associated with a second half of the four corner coordinates; and
determining an output pixel value for the center pixel block of the active region via a second one dimensional interpolation based at least in part on the determined first one dimensional interpolation, wherein the second one dimensional interpolation is associated with a second dimension of the image.

8. A non-transitory computer-readable storage medium having stored therein a plurality of instructions cause an apparatus to execute a method comprising:
associating a plurality of contrast compensation functions with a plurality of individual pixel blocks within an active block region portion of an image, wherein individual pixel bocks include one or more pixels associated with one or more corresponding pixel input values;
generating a weighted look-up-table based at least in part on the individual pixel input values within the active block region and on the plurality of contrast compensation functions;
performing a second level compensation for a center pixel block of the active region based at least in part on the weighted look-up-table; and
determining a first one dimensional interpolation based at least in part on the weighted look-up-table, wherein the first one dimensional interpolation is associated with a first dimension of the image, wherein the first one dimensional interpolation is based at least in part on a first portion associated with a first half of a four corner coordinates and a second portion associated with a second half of the four corner coordinates;
wherein generating the weighted look-up-table further comprises determining intermediate pixel values associated with four non-center corner coordinates for individual pixel input values on a pixel block by pixel block basis, wherein the intermediate pixel values associated with the four corner coordinates are stored in the weighted look-up-table.

9. The computer-readable storage medium of claim 8 , wherein the plurality of contrast compensation functions comprises a piecewise linear function-type contrast compensation function.

10. The computer-readable storage medium of claim 8 , wherein the plurality of contrast compensation functions comprises a look-up-table-type contrast compensation function.

11. The computer-readable storage medium of claim 8 , wherein the intermediate pixel values are determined based at least in part on weighting of a position of the four corner coordinates and on the plurality of contrast compensation functions.

12. The computer-readable storage medium of claim 8 , wherein performing the second level compensation for the center pixel block of the active region further comprises:
determining a first one dimensional interpolation based at least in part on the weighted look-up-table, wherein the first one dimensional interpolation is associated with a first dimension of the image; and
determining an output pixel value for the center pixel block of the active region via a second one dimensional interpolation based at least in part on the determined first one dimensional interpolation, wherein the second one dimensional interpolation is associated with a second dimension of the image.

Assignees

• Gupta Niraj
• Pal Supratim
• Chappalli Mahesh B
• Chiu Yi-Jen
• Jiang Hong
• Intel Corp

Inventors

• Gupta Niraj
• Pal Supratim
• Chappalli Mahesh B
• Chiu Yi-Jen
• Jiang Hong

Classifications

• G09G2320/066

  for control of contrast · CPC title

• G09G2320/029

  by monitoring one or more pixels in the display panel, e.g. by monitoring a fixed reference pixel · CPC title

• G09G5/06

  using colour palettes, e.g. look-up tables · CPC title

• H04N5/57 Primary

  Control of contrast or brightness · CPC title

• H04N21/4318

  by altering the content in the rendering process, e.g. blanking, blurring or masking an image region (image enhancement or restoration in general G06T5/00) · CPC title