Methods and systems for image compensation for ambient conditions

• US 8,531,379 B2
• Filed: 04/28/2008
• Issued: 09/10/2013
• Est. Priority Date: 04/28/2008
• 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 J.
• Primary Examiner(s): PHAM, VIET DAVID
• Application Number:
  US12/111,113
• Publication Number:
  US 20090267876A1
• Time in Patent Office: 1,961 Days
• Field of Search: 345/102, 345/204, 345/590
• US Class Current: 345/102
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/0238 Improving the black level
• 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 2320/0276 for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
• CPC Class Codes: G09G 2320/0285 using tables for spatial correction of display data
• CPC Class Codes: G09G 2320/062 Adjustment of illumination source parameters
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/066 for control of contrast
• 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 2340/0435 Change or adaptation of the frame rate of the video stream
• 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 3/2007 Display of intermediate tones
• CPC Class Codes: G09G 3/2044 using dithering
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: G09G 3/3607 for displaying colours or for displaying grey scales with a specific pixel layout, e.g. using sub-pixels display of colours in flat matrix panels other than liquid crystal displays G09G3/2003; grey scales specific for television H04N3/127

Abstract

Elements of the present invention relate to systems and methods for compensating an image for various ambient illumination conditions. In some embodiments, an image is compensated by modifying image code values to account for ambient conditions.

Claims

1. A method for determining an image compensation method, said method comprising:

a) selecting a reference ambient illumination level;

b) determining a reference retinal response based on said reference ambient illumination level using a retinal model, wherein said retinal model preserves retinal response under different ambient light levels by employing a relationship described in the following equations;

2. A method as described in claim 1 wherein said constants have the following values:

c₁=12.6 b=0.63 c₂=0

3. A method as described in claim 1 further comprising determining an image enhancement tonescale curve based on said image compensation value.

4. A method as described in claim 1 wherein said determining an image compensation value is also based on a display model.

5. A method as described in claim 1 wherein said determining an image compensation value is also based on a display reflectance model.

6. A method as described in claim 3 wherein said determining an image enhancement tonescale curve is also based on an original input image.

7. A method as described in claim 3 wherein said determining an image enhancement tonescale curve is also based on color values for an original input image.

8. A method for compensating an image for ambient illumination, said method comprising:

selecting a reference ambient illumination level;

determining a first backlight setting appropriate for said reference ambient illumination level;

determining an actual ambient illumination level in the vicinity of a display;

determining a second backlight setting appropriate for said actual ambient illumination level;

determining an image compensation scaling function according to the following equation,

9. A method as described in claim 8 wherein said image compensation scaling function is related to a display model.

10. A method as described in claim 8 wherein said image compensation scaling function is related to a display reflectance model.

11. A method as described in claim 8 wherein said image compensation scaling function is related to a transflective display model.

12. A method for compensating an image for ambient illumination, said method comprising:

selecting a reference ambient illumination level;

determining a first backlight setting appropriate for said reference ambient illumination level;

determining an actual ambient illumination level in the vicinity of a display;

determining a second backlight setting appropriate for said actual ambient illumination level;

determining an image compensation scaling function according to the equation;

13. A method for compensating an image for ambient illumination, said method comprising:

selecting a reference ambient illumination level;

determining a first backlight setting appropriate for said reference ambient illumination level;

determining an actual ambient illumination level in the vicinity of a display;

determining a second backlight setting appropriate for said actual ambient illumination level;

determining an image compensation scaling function according to the equation;

14. A system for compensating an image for ambient illumination, said system comprising:

a storage for a reference ambient illumination level;

a sensor for determining an actual ambient illumination level in the vicinity of a display;

a compensation calculator for determining an image compensation scaling function described in the following equation;

17. A system as described in claim 14 further comprising determining a display backlight compensation value based on said reference ambient illumination level and said actual ambient illumination level.

15. A system for compensating an image for ambient illumination, said system comprising:

a storage for a reference ambient illumination level;

a sensor for determining an actual ambient illumination level in the vicinity of a display;

a compensation calculator for determining an image compensation scaling function described in the following equation;

16. A system for compensating an image for ambient illumination, said system comprising:

a storage for a reference ambient illumination level;

a sensor for determining an actual ambient illumination level in the vicinity of a display;

a compensation calculator for determining an image compensation scaling function described in the following equation;