High dynamic range image generation and rendering
First Claim
1. One or more computer-readable memory or storage devices storing instructions that, when executed by a computing device, perform a method of rendering a high dynamic range digital image as a lower dynamic range digital image, the method comprising:
- tone mapping each of plural sample values in a high dynamic range digital image to a respective lower dynamic range value;
calculating a local contrast value for each of the tone-mapped sample values;
deriving a residual signal for each of the tone-mapped sample values, the deriving based at least in part on the respective local contrast value; and
calculating sample values for a lower dynamic range digital image based at least in part on the tone-mapped sample values and the respective residual signals.
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Abstract
Techniques and tools for high dynamic range (HDR) image rendering and generation. An HDR image generating system performs motion analysis on a set of lower dynamic range (LDR) images and derives relative exposure levels for the images based on information obtained in the motion analysis. These relative exposure levels are used when integrating the LDR images to form an HDR image. An HDR image rendering system tone maps sample values in an HDR image to a respective lower dynamic range value, and calculates local contrast values. Residual signals are derived based on local contrast, and sample values for an LDR image are calculated based on the tone-mapped sample values and the residual signals. User preference information can be used during various stages of HDR image generation or rendering.
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Citations
24 Claims
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1. One or more computer-readable memory or storage devices storing instructions that, when executed by a computing device, perform a method of rendering a high dynamic range digital image as a lower dynamic range digital image, the method comprising:
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tone mapping each of plural sample values in a high dynamic range digital image to a respective lower dynamic range value; calculating a local contrast value for each of the tone-mapped sample values; deriving a residual signal for each of the tone-mapped sample values, the deriving based at least in part on the respective local contrast value; and calculating sample values for a lower dynamic range digital image based at least in part on the tone-mapped sample values and the respective residual signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 13)
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10. In a computer system, a method of rendering a high dynamic range image based on user preference information, the method comprising:
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providing one or more user preference controls for setting user preferences for high dynamic range image rendering parameters; receiving user preference information associated with a user from the user preference controls, the user preference information corresponding to high dynamic range image rendering parameters for a high dynamic range digital image file containing a high dynamic range digital image; and rendering the high dynamic range digital image based at least in part on the user preference information; wherein the rendering comprises; calculating a local contrast value for each of plural tone-mapped sample values; deriving a residual signal for each of the plural tone-mapped sample values, the deriving being based at least in part on the respective local contrast value; and calculating sample values for a lower dynamic range digital image based at least in part on the plural tone-mapped sample values and the respective residual signals. - View Dependent Claims (11, 12, 14)
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15. A high dynamic range digital image rendering system comprising:
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a lookup table containing a plurality of high dynamic range (HDR) digital image sample values and corresponding lower dynamic range (LDR) sample values; a tone mapper that obtains LDR sample values from the lookup table that correspond to sample values of an HDR digital image being rendered to create tone-mapped sample values; a residual signal extractor that; calculates local contrast values for the tone-mapped sample values, and derives residual signals for the tone-mapped sample values by multiplying the tone-mapped sample values by the corresponding local contrast values; an LDR image generator that generates samples for an output LDR image based on the tone mapped sample values and the residual signals; and at least one processor that communicates with the tone mapper, residual signal extractor, and LDR image generator to perform the respective functions. - View Dependent Claims (16, 17, 18, 19, 20)
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21. A computer-implemented method of rendering a high dynamic range digital image as a lower dynamic range digital image, the method comprising:
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tone mapping each of plural sample values in a high dynamic range digital image to a respective lower dynamic range value; calculating a local contrast value for each of the tone-mapped sample values; deriving a residual signal for each of the tone-mapped sample values, the deriving based at least in part on the respective local contrast value; and calculating sample values for a lower dynamic range digital image based at least in part on the tone-mapped sample values and the respective residual signals. - View Dependent Claims (22, 23, 24)
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Specification