Enhancing dynamic ranges of images
First Claim
Patent Images
1. A method for enhancing lower-dynamic range (LDR) image data representing an image, the method comprising:
- identifying at least one enhancement region within the image;
generating a brightness enhancement function, wherein generating the brightness enhancement function comprises;
generating a mask which identifies pixels inside and outside of the enhancement region;
applying a blur filter to the mask to obtain grey-scale image data;
applying the brightness enhancement function to the LDR image data to generate higher-dynamic range (HDR) image data, wherein compared to the LDR image data, the HDR image data comprises increased luminance values of enhancement-region pixels in the enhancement region and increased luminance values of one or more boundary-region pixels outside of the enhancement region, the luminance value increase of the boundary-region pixels decreasing with distance from the enhancement region.
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Abstract
Methods and apparatus according to various aspects take as input image data in a lower-dynamic-range (LDR) format and produce as output enhanced image data having a dynamic range greater than that of the input image data (i.e. higher-dynamic range (HDR) image data). In some embodiments, the methods are applied to video data and are performed in real-time (i.e. processing of video frames to enhance the dynamic range of the video frames is completed at least on average at the frame rate of the video signal).
17 Citations
54 Claims
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1. A method for enhancing lower-dynamic range (LDR) image data representing an image, the method comprising:
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identifying at least one enhancement region within the image; generating a brightness enhancement function, wherein generating the brightness enhancement function comprises; generating a mask which identifies pixels inside and outside of the enhancement region; applying a blur filter to the mask to obtain grey-scale image data; applying the brightness enhancement function to the LDR image data to generate higher-dynamic range (HDR) image data, wherein compared to the LDR image data, the HDR image data comprises increased luminance values of enhancement-region pixels in the enhancement region and increased luminance values of one or more boundary-region pixels outside of the enhancement region, the luminance value increase of the boundary-region pixels decreasing with distance from the enhancement region. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40)
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41. A non-transitory computer-readable medium comprising a series of instructions which, when executed by a suitably configured processor, cause the processor to perform a method for enhancing lower-dynamic range (LDR) image data representing an image, the method comprising:
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identifying at least one enhancement region within the image; generating a brightness enhancement function, wherein generating the brightness enhancement function comprises; generating a mask which identifies pixels inside and outside of the enhancement region; applying a blur filter to the mask to obtain grey-scale image data; applying the brightness enhancement function to the LDR image data to generate higher-dynamic range (HDR) image data, wherein compared to the LDR image data, the HDR image data comprises increased luminance values of enhancement-region pixels in the enhancement region and increased luminance values of one or more boundary-region pixels outside of the enhancement region, the luminance value increase of the boundary-region pixels decreasing with distance from the enhancement region. - View Dependent Claims (42, 43, 44, 45, 46, 47, 48, 49, 50)
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51. A display for displaying a higher-dynamic range (HDR) image obtained from lower-dynamic range (LDR) image data representing an image, the display comprising:
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a pair of modulators comprising; a first modulator configured to provide a light pattern varying in response to a set of driving signals; and a second modulator configured to modulate the light pattern to yield an output image; and a processor configured to; identify at least one enhancement region within the image; generate a brightness enhancement function and wherein generating the brightness enhancement function inv olves generating an edge-stopping component of the brightness enhancement function based at least in part on a gradient image of the LDR image data, the edge-stopping component having pixel values which indicate whether or not application of the brightness enhancement function should increase the luminance of a corresponding pixels of the LDR image data and wherein the intermediate data comprises a low resolution version of the edge-stopping component; apply the brightness enhancement function to the LDR image data to generate the HDR image data, wherein compared to the LDR image data, the HDR image data comprises increased luminance values of enhancement-region pixels in the enhancement region and increased luminance values of one or more boundary-region pixels outside of the enhancement region, the luminance value increase of the boundary-region pixels decreasing with distance from the enhancement region; and
determine the driving signals for the first modulator based at least in part on intermediate data obtained in the course of application of the brightness enhancement function to the LDR image data. - View Dependent Claims (52, 54)
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53. A method for displaying a higher-dynamic range (HDR) image obtained from lower-dynamic range (LDR) image data, the method comprising:
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identifying at least one enhancement region within the LDR image data; generating a brightness enhancement function and wherein generating the brightness enhancement function comprises generating an edge-stopping component of the brightness enhancement function based at least in part on a gradient image of the LDR image data, the edge-stopping component having pixel values which indicate whether or not application of brightness enhancement function should increase the luminance of corresponding pixels of the LDR image data and wherein the intermediate data comprises a low resolution version of the edge-stopping component; applying the brightness enhancement function to the LDR image data to generate the HDR image data, wherein compared to the LDR image data, the HDR image data comprises increased luminance values of enhancement-region pixels in the enhancement region and increased luminance values of one or more boundary-region pixels outside of the enhancement region, the luminance value increase of the boundary-region pixels decreasing with distance from the enhancement region; and determining driving signals for at least one modulator of a dual-modulator display based at least in part on intermediate data obtained in the course of application of the brightness enhancement function to the LDR image data.
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Specification