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

• US 9,633,587 B2
• Filed: 11/03/2014
• Issued: 04/25/2017
• 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): Nguyen, Chanh
• Assistant Examiner(s): STONE, ROBERT M
• Application Number:
  US14/531,503
• Publication Number:
  US 20150049132A1
• Time in Patent Office: 904 Days
• 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. A display, comprising:

a modulating device;

a plurality of light emitters arranged to illuminate modulating elements of the modulating device with a spatially modulated light according to image data, wherein, for each modulating element, there is a subset of the plurality of light emitters that illuminate the each modulating element;

a controller configured to determine a set of intermediate samples comprising more samples than light emitters wherein each sample comprises a calculation based on the subset of the plurality of the light emitters and based on a point spread function of the subset of the light emitters, and wherein the controller determines a control signal for each modulating element of the modulating device based on a division of a portion of the image data and at least one sample corresponding to the portion of the image data, such that the division comprises a non-linear inversion of luminance values wherein the luminance values are tested prior to inversion whether the luminance values are above a desired threshold and, if not, the luminance values are clamped to the desired threshold; and

said controller connected to the modulating device in a manner that energizes the modulating device according to the control signal such that the spatially modulated light from the plurality light emitters spreading together as determined in the set of intermediate samples is further modulated.

2. The display according to claim 1, wherein the division comprises a non-linear inversion of luminance values mixed together from a plurality of the light emitters.

3. The display according to claim 2, wherein the energization of the modulating elements is based on an adjustment that enhances edge luminance of predicted backlight values.

4. The display according to claim 1, wherein the light emitters comprise laser light emitters, the modulating device comprises a DMD.

5. A projector comprising:

a plurality of modulating elements;

a plurality of light emitters arranged to illuminate modulating elements of the modulating device with a spatially modulated light according to image data, wherein, for each modulating element, there is a subset of the plurality of light emitters that illuminate the each modulating element;

a controller configured to energize the modulator so as to produce a desired image;

wherein the controller determines a set of intermediate samples comprising more samples than light emitters wherein each sample comprises a calculation based on the subset of the plurality of the light emitters and based on a point spread function defining how light from the the subset of the light emitters spreads on its path to the modulator, and wherein the controller determines a control signal for each modulating element of the modulator based on a division of a portion of the image data and at least one sample corresponding to the portion of the image data, such that the division comprises a non-linear inversion of luminance values wherein the luminance values are tested prior to inversion whether the luminance values are above a desired threshold and, if not, the luminance values are clamped to the desired threshold.

6. The projector according to claim 5, wherein the controller is connected to the modulator in a manner that energizes the modulating device according to the control signal such that spatially modulated light comprising a low resolution image from the plurality of light emitters spreading together as determined in the set of intermediate samples is further modulated.

7. The projector according to claim 5, wherein the division comprises a non-linear inversion of luminance values mixed together from a plurality of the light emitters.

8. A method comprising the steps of:

a primary modulator comprising a plurality of modulating elements;

energizing a source of modulated light comprising a plurality of light emitters arranged to illuminate modulating elements of the modulating device with a spatially modulated light according to image data, wherein, for each modulating element, there is a subset of the plurality of light emitters that illuminate the each modulating element;

directing a low resolution version of an image to the primary modulator;

determining a set of intermediate samples comprising more samples than light emitters wherein each sample comprises a calculation based on the subset of the plurality of the light emitters and based on a point spread function defining how light from the subset of the light emitters spreads and mixes while on its path to the primary modulator;

determining a control signal for each modulating element of the primary modulator based on a division of a portion of the image data and at least one sample corresponding to the portion of the image data, such that the division comprises a non-linear inversion of luminance values wherein the luminance values are tested prior to inversion whether the luminance values are above a desired threshold and, if not, the luminance values are clamped to the desired threshold; and

energizing the primary modulator with the control signal such that the low resolution version of the image is further modulated so as to produce a desired image.

9. The method according to claim 8, wherein the control signal is produced taking into account the low resolution image from the plurality of light emitters spreading together as determined in the set of intermediate samples is how the low resolution version of the image is to be further modulated.

10. The method according to claim 8, wherein the division comprises a non-linear inversion of luminance values mixed together from a plurality of the light emitters.

11. The method according to claim 8, wherein the steps related to control are coded as computer readable instructions in a controller.