Backlight simulation at reduced resolutions to determine spatial modulation of light for high dynamic range images

• US 8,890,902 B2
• Filed: 10/02/2009
• Issued: 11/18/2014
• Est. Priority Date: 10/14/2008
• Status: Active Grant

• Current Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Original Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Inventors: Johnson, Lewis
• Primary Examiner(s): Pappas, Claire X
• Assistant Examiner(s): STONE, ROBERT M
• Application Number:
  US13/123,569
• Publication Number:
  US 20110193896A1
• Time in Patent Office: 1,873 Days
• Field of Search: 345/690, 345/102
• US Class Current: 345/690
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/20012 Locally adaptive
• CPC Class Codes: G06T 5/92 based on global image properties
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2340/0407 Resolution change, inclusive of the use of different resolutions for different screen areas
• CPC Class Codes: G09G 3/002 to project the image of a two-dimensional display, such as an array of light emitting or modulating elements or a CRT
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix
• CPC Class Codes: G09G 3/36 using liquid crystals
• CPC Class Codes: H04N 5/142 Edging; Contouring

Abstract

Embodiments of the invention relate generally to generating images with an enhanced range of brightness levels, and more particularly, to facilitating high dynamic range imaging by adjusting pixel data and/or using predicted values of luminance, for example, at different resolutions. In at least one embodiment, a method generates an image with an enhanced range of brightness levels. The method can include accessing a model of backlight that includes data representing values of luminance for a number of first samples. The method also can include inverting the values of luminance, as well as upsampling inverted values of luminance to determine upsampled values of luminance. Further, the method can include scaling pixel data for a number of second samples by the upsampled values of luminance to control a modulator to generate an image.

Claims

1. An apparatus comprising:

a repository comprising;

a data structure configured to arrange data representing predicted values of luminance for a number of samples that is greater in quantity than a number of light sources;

a memory comprising;

an inverter module, an upsampler module, and a pixel scaler module; and

a processor configured to;

access the data structure to fetch the data representing the predicted values of luminance,

invert the predicted values of luminance, responsive to executable instructions in the inverter module, to establish a quantity of inverted values of luminance that is substantially equivalent to the number of samples,

upsample the inverted values of luminance, responsive to executable instructions in the upsampler module, to generate a quantity of upsampled inverted values of luminance that is substantially equivalent to a number of pixels, and

scale pixel data by the up sampled inverted values of luminance, responsive to executable instructions in the pixel scaler module, to form a modulation signal to control a front modulator to generate an image.

2. The apparatus according to claim 1, wherein

the predicted values of luminance are associated with a model of backlight.

3. The apparatus according to claim 1,

scaling a value of the pixel characteristic as wherein the scaled pixel data comprises scaling via a function of distance from a location of a sample to a reference point at an edge of the display or a region or point with reduced peak luminance.

4. The apparatus according to claim 1 wherein the inverted values of luminance comprise one of:

an inversion of each of values of pixel characteristics associated with a group of pixels to establish an inverted value of the pixel characteristic; and

a division of values of pixel characteristics modified so that its result is clamped to a finite value for the inverted values.

5. The apparatus according to claim 1 wherein the predicted values of luminance are inverted by

divide operations that are modified so that their results are clamped to finite values for the inverted values of the pixel characteristic,

wherein the number of divide operations is substantially equivalent to the number of first samples.

6. The apparatus according to claim 1 wherein

the inverted values of luminance are adjusted to modify an amount of light transmitted via the modulator, comprising determining a scaling factor based on an operational characteristic of a light source configured to project light onto the modulator, and scaling the inverted values of the pixel characteristic by the scaling factor.

7. The apparatus of claim 1 further comprising:

an edge luminance enhancement module, the processor being further configured to generate an edge-enhanced value for one of the inverted values of luminance, responsive to executable instructions in the edge luminance enhancement module that scale a value of luminance as a function of the distance from a location of the sample associated with the value of luminance from a reference point,

wherein the reference point substantially coincides with an edge of a display device.

8. A controller, comprising:

an inverter configured to invert values of a pixel characteristic to establish inverted values of the pixel characteristic, the values of the pixel characteristic being predicted values of the pixel characteristic that constitute a model of backlight for a number of first samples;

an upsampler configured to upsample the inverted values of the pixel characteristic to determine upsampled inverted values of the pixel characteristic; and

a pixel scaler configured to scale pixel data for a number of second samples by the upsampled inverted values of the pixel characteristic to control a modulator to generate an image, and

an edge luminance enhancer configured to scale a value of the pixel characteristic as a function of a distance from a location of a first sample associated with the value of the pixel characteristic to a reference point comprising an edge of a display device

wherein the number of second samples is greater than the number of first samples

and wherein the edge luminance enhancer comprises,

a sample locator configured to determine a profiled value of the pixel characteristic as a function of the distance, and

a sample scaler configured to divide the value of the pixel characteristic by the profiled value to form a modified predicted value of the pixel characteristic.

9. The controller of claim 8 wherein the upsampler is configured to:

perform bilateral interpolation on the inverted values of the pixel characteristic to form interpolated inverted values of the pixel characteristic.