Method and apparatus for detecting and processing noisy edges in image detail enhancement
First Claim
1. A method of detail enhancement for an original image signal represented by a set of pixels, the method comprising the steps of:
- (a) detecting image pixels that belong to an image edge;
(b) for a detected pixel, generating an unsharp image signal at the detected pixel location;
(c) determining the difference between the original image signal and the unsharp signal, wherein said difference represents image details; and
(d) boosting the difference signal and adding the boosted signal to the original signal to obtain a detail enhanced image signal;
whereby boosting of any noise at the selected pixel location is reduced.
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Abstract
A method and system that detect image pixels of noisy and sharp image edges, and enhance such pixels differently than other pixels, so that noise around the detected pixels is essentially not boosted. A detection process is conducted on a pixel basis, wherein each pixel is checked together with its neighboring pixels inside a rectangular window centered around a selected/current pixel to determine whether the current pixel belongs to a noisy and sharp vertical image edge or a noisy and sharp horizontal image edge. If the current pixel is classified as a regular pixel, image detail enhancement is performed normally at the current pixel location. Otherwise, mean values of pixels in a rectangular window centered with the current pixel are used to calculate the unsharp signal. The unsharp signal is then processed as in the case of the regular pixels to obtain a detail enhanced image.
20 Citations
74 Claims
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1. A method of detail enhancement for an original image signal represented by a set of pixels, the method comprising the steps of:
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(a) detecting image pixels that belong to an image edge; (b) for a detected pixel, generating an unsharp image signal at the detected pixel location; (c) determining the difference between the original image signal and the unsharp signal, wherein said difference represents image details; and (d) boosting the difference signal and adding the boosted signal to the original signal to obtain a detail enhanced image signal; whereby boosting of any noise at the selected pixel location is reduced. - 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)
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26. An image detail enhancement system for enhancing an original image signal represented by a set of pixels, comprising:
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(a) a detector that detects image pixels that belong to an image edge; and (b) an edge enhancer that, for a detected pixel, generates an unsharp image signal at the detected pixel location, determines the difference between the original image signal and the unsharp signal, wherein said difference represents image details, boosts the difference signal and adds the boosted signal to the original signal to obtain a detail enhanced image signal, whereby boosting of any noise at the selected pixel location is reduced. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50)
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51. An image detail enhancement system for enhancing an original image signal represented by a set of pixels, comprising:
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(a) a detector that detects image pixels that belong to an image edge; (b) an edge enhancer that, for a detected pixel, generates an unsharp image signal at the detected pixel location, determines the difference between the original image signal and the unsharp signal, wherein said difference represents image details, boosts the difference signal and adds the boosted signal to the original signal to obtain a detail enhanced image signal, whereby boosting of any noise at the selected pixel location is reduced; and (c) a normal enhancer, wherein for a pixel that is not detected as belonging to an image edge, the normal enhancer performs a filtering process on the pixel to obtain an unsharp signal at that pixel location, determines the difference between the original signal and the unsharp signal at the pixel location, wherein the difference represents image detail, boosts the image detail and adds the boosted image detail to the original image signal to obtain a detail enhanced image; wherein upon determining that an image pixel belongs to an image edge, the detector selects the edge enhancer to enhance that image pixel, and upon determining that an image pixel does not belong to an image edge, the detector selects the normal enhancer to enhance that image pixel. - View Dependent Claims (52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74)
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Specification