Systems and methods for tone curve generation, selection and application

• US 8,120,570 B2
• Filed: 08/27/2007
• Issued: 02/21/2012
• Est. Priority Date: 12/02/2004
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Laboratories of America Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Kerofsky, Louis J.
• Primary Examiner(s): Wu, Xiao M.
• Assistant Examiner(s): Sonners, Scott E
• Application Number:
  US11/845,651
• Publication Number:
  US 20070291048A1
• Time in Patent Office: 1,639 Days
• Field of Search: 345/102
• US Class Current: 345/102
• CPC Class Codes: G09G 2320/0238 Improving the black level
• CPC Class Codes: G09G 2320/0271 Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2320/0653 Controlling or limiting the speed of brightness adjustment of the illumination source
• CPC Class Codes: G09G 2320/066 for control of contrast
• CPC Class Codes: G09G 2320/0673 for control of gamma adjustment, e.g. selecting another gamma curve
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/2003 Display of colours specific for liquid crystal displays G09G3/3607
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336

Abstract

Embodiments of the present invention comprise systems and methods for calculating and selecting tone curves for image enhancement.

Claims

1. A method for adjusting image characteristics on a display device having a processor, said method comprising:

a) generating a panel tone curve and generating a plurality of candidate tone curves, wherein each of said candidate tone curves comprises a black level transition region corresponding to a different backlight brightness level for each candidate tone curve and an identified common region that is substantially similar in each candidate tone curve and said panel tone curve;

b) said processor analyzing an image to determine an image characteristic;

c) said processor selecting a candidate tone curve from said plurality of candidate tone curves, wherein said selecting is based on said image characteristic; and

d) said processor applying said selected candidate tone curve to said image thereby creating an adjusted image.

2. A method as described in claim 1 wherein each of said plurality of candidate tone curves also comprises a brightness round-off curve.

3. A method as described in claim 1 wherein said selecting a selected target candidate tone curve is also based on a performance goal.

4. A method as described in claim 1 where said processor selects said candidate tone curve by comparing said image characteristic represented in said panel tone curve to said image characteristic represented in respective ones of said plurality of candidate tone curves.

5. A method as described in claim 1 wherein said image characteristic is an image dynamic range.

6. A method as described in claim 1 further comprising generating a plurality of enhanced candidate tone curves, wherein each of said enhanced candidate tone curves comprises a black level transition region corresponding to a different backlight brightness level for each enhanced candidate tone curve and an enhanced common region that is substantially similar in each candidate tone curve, but wherein said enhanced common region maps input values to higher output values than said common region;

and wherein said selecting a selected candidate tone curve comprises selecting from said plurality of candidate tone curves and said plurality of enhanced candidate tone curves.