Methods and systems for determining a display light source adjustment

• US 7,924,261 B2
• Filed: 12/02/2005
• Issued: 04/12/2011
• Est. Priority Date: 12/02/2004
• Status: Expired due to Fees

• 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 Joseph
• Primary Examiner(s): Awad; Amr
• Assistant Examiner(s): Bukowski; Kenneth
• Application Number:
  US11/293,562
• Publication Number:
  US 20060209003A1
• Time in Patent Office: 1,957 Days
• Field of Search: 345 87-104, 345204-215, 345690-699
• US Class Current: 345/102
• CPC Class Codes: G09G 2320/02 Improving the quality of display appearance
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/0242 Compensation of deficiencies in the appearance of colours
• 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 2320/0285 using tables for spatial correction of display data
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/0633 by amplitude modulation of the brightness of the illumination source
• 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 2320/0673 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 2340/0428 Gradation resolution change
• 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 3/22 using controlled light sources
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources

Abstract

Embodiments of the present invention comprise systems, methods and devices for adjusting display light source levels for enhanced image display.

Claims

1. A method for determining a display source light reduction factor, said method comprising:

analyzing an input image histogram for a first color channel of said input image;

determining a first clipped percentage of pixels that are clipped in said first color channel of said input image;

determining a first clipped code value, Cv_clipped, corresponding to said first clipped percentage of pixels that are clipped;

determining a first distorted percentage of pixels that are distorted in said first color channel of said input image;

determining a first distorted code value, Cv_distorted, corresponding to said first distorted percentage of pixels that are distorted; and

calculating a source light reduction factor that is proportional to a quantity raised to the power of a display gamma value, wherein said quantity is equal to the average of said Cv_distorted and said Cv_clipped divided by a maximum value of said first color channel.

2. A method as described in claim 1 further comprising:

analyzing an input image histogram for a second color channel of said input image;

determining second clipped code values for said second color channel of said input image and selecting the maximum of said first clipped code values and said second clipped code values for said calculating.

3. A method as described in claim 2 further comprising;

analyzing an input image histogram for a third color channel of said input image;

determining third clipped code values for said third color channel of said input image and selecting the maximum of said first clipped code values, said second clipped code values and said third clipped code values for said calculating.

4. A method as described in claim 1 wherein said source light reduction factor is proportional to:

5. A method for determining a display source light reduction factor, said method comprising:

analyzing an input image histogram for a first color channel of said input image;

determining a first clipped percentage of pixels that are clipped in said first color channel of said input image;

analyzing an input image histogram for a second color channel of said input image;

determining a second clipped percentage of pixels that are clipped in said second color channel of said input image;

selecting a maximum clipped percentage value of said first clipped percentage and said second clipped percentage;

determining a maximum clipped code value, Cv_clipped, based on said maximum clipped percentage value;

determining a first distorted percentage of pixels that are distorted in said second color channel of said input image;

determining a second distorted percentage of pixels that are distorted in said second color channel of said input image;

selecting a maximum distorted percentage value of said first distorted percentage of pixels that are distorted and said second distorted percentage of pixels that are distorted;

determining a maximum distorted code value, Cv_distorted, based on said maximum distorted percentage value; and

calculating a source light reduction factor that is proportional to a quantity raised to the power of a display gamma value, wherein said quantity is equal to the average of said Cv_distorted and said Cv_clipped divided by a maximum value of said first color channel and said second color channel.

6. An apparatus for determining a display source light reduction factor, said apparatus comprising:

a first color channel analyzer for determining a first clipped percentage of clipped pixels in a first image color channel;

a second color channel analyzer for determining a second clipped percentage of clipped pixels in a second image color channel;

a clipped percentage selector for selecting a maximum clipped percentage value of said first clipped percentage of clipped pixels and said second clipped percentage of clipped pixels;

a first clipped code value selector for determining a clipped code value, Cv_clipped corresponding to said maximum clipped percentage value;

a third color channel analyzer for determining a first distorted percentage of distorted pixels in said first image color channel;

a fourth color channel analyzer for determining a second distorted percentage of distorted pixels in said second image color channel;

a distorted percentage selector for selecting a maximum distorted percentage value of said first distorted percentage of distorted pixels and said second distorted percentage of distorted pixels;

a distorted code value selector for determining a distorted code value, Cv_distorted, corresponding to said maximum distorted percentage value; and

a processor for calculating a source light reduction factor that is proportional to a quantity raised to the power of a display gamma value, wherein said quantity is equal to the average of said Cv_distorted and said Cv_clipped divided by a maximum value of said first color channel and said second color channel.