Methods and systems for enhancing display characteristics

• US 7,800,577 B2
• Filed: 06/15/2005
• Issued: 09/21/2010
• 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, Daly, Scott James
• Primary Examiner(s): Dinh; Duc Q
• Application Number:
  US11/154,052
• Publication Number:
  US 20060284822A1
• Time in Patent Office: 1,924 Days
• Field of Search: 345/102, 345/204, 345/690, 345 98-100
• US Class Current: 345/102
• CPC Class Codes: G09G 2320/02 Improving the quality of display appearance
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/36 using liquid crystals

Abstract

Embodiments of the present invention comprise systems, methods and devices for increasing the perceived brightness of an image. In some embodiments this increase compensates for a decrease in display light source illumination.

Claims

1. A method for compensating for a display light source illumination reduction, said method comprising:

determining a source light illumination reduction level;

determining a maximum fidelity point (MFP) at which a roll-off from matching reduced-power output to full-power output occurs;

adjusting first original code values of an input image with values above said MFP, thereby producing first adjusted code values, wherein said first adjusted code values, when displayed using said display light source illumination reduction, will produce the same luminance as said corresponding original code values produce using a full source light illumination level; and

adjusting second original code values of said input image with values above said MFP, thereby producing second adjusted code values, wherein said second adjusted code values are fitted to a round-off curve to avoid clipping.

2. A method as described in claim 1 wherein said display is a light-valve-modulated display and said adjusting increases the light modulated by said light valves.

3. A method as described in claim 1 wherein said adjusting first original code values comprises multiplying said code values by a constant gain multiplier.

4. A method as described in claim 1 wherein said adjusting first original code values is dependent on at least one of a display gamma, an efficiency factor and a maximum fidelity point (MFP).

5. A method as described in claim 1 wherein said roll-off curve begins at said MFP and ends at a point that maps the maximum code value to the maximum display level.

6. A method as described in claim 5 wherein said roll-off curve matches the slope of a tone scale curve used for said adjusting said first original code values at said MFP point.

7. A method as described in claim 5 wherein said roll-off curve has a slope of zero at an end point.