Automatic contrast enhancement
First Claim
1. A process for enhancing contrast of an image having pixels in different brightness intensities, the process comprising:
- generating a histogram in discrete bins, each bin representing a pixel population of at least one pixel brightness intensity;
computing a smoothened line curve from the generated histogram;
computing an average pixel population of the histogram;
identifying a peak and a peak region of the histogram, wherein the peak region is a range of discrete bins around the peak bounded by intersection of the smoothened line curve with the computed average pixel population of the histogram;
computing an average pixel population of the peak region;
distributing the pixel populations of the discrete bins within the peak region that exceed the average pixel population of the peak region to produce a re-distributed histogram, wherein distributing is limited to the discrete bins within the peak region; and
generating a transfer curve for mapping onto the image from the re-distributed histogram.
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Accused Products
Abstract
In a process for enhancing contrast of an image having pixels in different brightness intensities, a histogram in discrete bins is generated. Each bin represents a pixel population of at least one pixel brightness intensity. A peak and a peak region of the histogram is then identified, wherein the peak region is a range of discrete bins around the peak. An average pixel population within the peak region is computed, and the pixel populations of the discrete bins within the peak region that exceeds the average pixel population are distributed. A transfer curve for mapping onto the image is then generated. The process can be used in an image processor for enhancing contrast of an image having pixel. Still further, a display having a receiver and a screen can include the foregoing image processor.
40 Citations
43 Claims
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1. A process for enhancing contrast of an image having pixels in different brightness intensities, the process comprising:
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generating a histogram in discrete bins, each bin representing a pixel population of at least one pixel brightness intensity; computing a smoothened line curve from the generated histogram; computing an average pixel population of the histogram; identifying a peak and a peak region of the histogram, wherein the peak region is a range of discrete bins around the peak bounded by intersection of the smoothened line curve with the computed average pixel population of the histogram; computing an average pixel population of the peak region; distributing the pixel populations of the discrete bins within the peak region that exceed the average pixel population of the peak region to produce a re-distributed histogram, wherein distributing is limited to the discrete bins within the peak region; and generating a transfer curve for mapping onto the image from the re-distributed histogram. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. An image processor for enhancing contrast of an image having pixels comprising:
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a histogram generator adapted to generate a histogram in discrete bins, each bin representing a pixel population of at least one pixel brightness intensity; a histogram pre-processor adapted to compute a smoothened line curve for the generated histogram; a peak analyzer adapted to compute an average pixel population of the histogram, identify a peak and a peak region, and compute an average pixel population of the peak region, wherein the peak region is a range of discrete bins around the peak bounded by intersection of the smoothened line curve with the computed average pixel population of the histogram; a pixel distributor adapted to distribute the pixel populations of the discrete bins within the peak region that exceed the average pixel population of the peak region to produce a re-distributed histogram, wherein distributing is limited to the discrete bins within the peak region; and a transfer curve generator adapted to generate from the re-distributed histogram a transfer curve for mapping onto the image. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42)
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43. A process for enhancing contrast of an image having pixels in different brightness intensities, the process comprising:
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generating a histogram in discrete bins, each bin representing a pixel population of at least one pixel brightness intensity; computing an average pixel population of the histogram; identifying a peak and a peak region of the histogram, wherein the peak region is a range of discrete bins around the peak defined between a lower bin and an upper bin wherein the pixel population for each of the discrete bins of the peak region exceeds the computed average pixel population of the histogram; computing an average pixel population of the peak region; distributing the pixel populations of the discrete bins within the peak region that exceed the average pixel population of the peak region to produce a re-distributed histogram, wherein distributing is limited solely to the discrete bins within the peak region and any excess pixel populations which cannot be distributed to the discrete bins within the peak region are truncated; and generating a transfer curve for mapping onto the image from the re-distributed histogram.
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Specification