Noise reduction method and noise reduction apparatus
First Claim
1. A noise reduction method, applied in a display, for use in reducing noise of a digital image, the method comprising steps of:
- providing a plurality of luminance threshold values;
determining a plurality of luminance feature values according to a luminance value of a target pixel and luminance values of neighboring pixels of the target pixel by a calculating unit of the display;
determining whether the target pixel is a noise point, by a comparing unit of the display, based on the comparison between each of the luminance feature values and each of the luminance threshold values corresponding thereto, respectively; and
adjusting the luminance value of the target pixel, by an adjusting unit of the display, when the target pixel is determined as the noise point;
wherein a first luminance feature value of the luminance feature values is determined by the luminance value of the target pixel and the luminance values of first four neighboring pixels, and the target pixel and the first four neighboring pixels form a cross shape;
wherein a second luminance feature value of the luminance feature values is determined by the luminance value of the target pixel and the luminance values of second four neighboring pixels, and the target pixel and the second four neighboring pixels form an X shape;
wherein the first luminance feature value is expressed as;
CV1=abs[Yr1+Yr2+Yr3+Yr4−
K1×
Yt], wherein CV1 is the first luminance feature value, Yt is the luminance value of the target pixel, Yr1, Yr2, Yr3, Yr4 are respectively the luminance values of the first four neighboring pixels that form the cross shape with the target pixel, K1 is a constant and abs is an absolute value operator.
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Abstract
The present invention provides a noise reduction method for use in reducing noise of a digital image, the method comprising steps of: providing a plurality of luminance threshold values; determining a plurality of luminance feature values according to the luminance value of a target pixel and the luminance values of neighboring pixels of the target pixel; determining whether the target pixel is a noise point based on the comparison between each of the luminance feature values and each of the luminance threshold values corresponding thereto, respectively; and adjusting the luminance value, a first chrominance value and a second chrominance value of the target pixel if the target pixel is determined as a noise point. Using the noise reduction method of the present invention, not only noise of a digital image can be identified, but also the degradation caused by the noise can be reduced and thus the overall picture quality can be improved.
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Citations
18 Claims
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1. A noise reduction method, applied in a display, for use in reducing noise of a digital image, the method comprising steps of:
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providing a plurality of luminance threshold values; determining a plurality of luminance feature values according to a luminance value of a target pixel and luminance values of neighboring pixels of the target pixel by a calculating unit of the display; determining whether the target pixel is a noise point, by a comparing unit of the display, based on the comparison between each of the luminance feature values and each of the luminance threshold values corresponding thereto, respectively; and adjusting the luminance value of the target pixel, by an adjusting unit of the display, when the target pixel is determined as the noise point; wherein a first luminance feature value of the luminance feature values is determined by the luminance value of the target pixel and the luminance values of first four neighboring pixels, and the target pixel and the first four neighboring pixels form a cross shape; wherein a second luminance feature value of the luminance feature values is determined by the luminance value of the target pixel and the luminance values of second four neighboring pixels, and the target pixel and the second four neighboring pixels form an X shape; wherein the first luminance feature value is expressed as;
CV1=abs[Yr1+Yr2+Yr3+Yr4−
K1×
Yt],wherein CV1 is the first luminance feature value, Yt is the luminance value of the target pixel, Yr1, Yr2, Yr3, Yr4 are respectively the luminance values of the first four neighboring pixels that form the cross shape with the target pixel, K1 is a constant and abs is an absolute value operator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A noise reduction apparatus, applied in a display, for use in reducing noise of a digital image, the apparatus comprising:
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a calculating unit, for determining a plurality of luminance feature values according to a luminance value of a target pixel of the digital image and luminance values of neighboring pixels of the target pixel; a comparing unit, for determining whether the target pixel is a noise point based on the comparison between each of the luminance feature values and each of luminance threshold values corresponding thereto, respectively; and an adjusting unit, adjusting the luminance value of the target pixel when the target pixel is determined as the noise point; wherein a first luminance feature value of the luminance feature values is determined by the luminance value of the target pixel and the luminance values of first four neighboring pixels, and the target pixel and the first four neighboring pixels form a cross shape; wherein a second luminance feature value of the luminance feature values is determined by the luminance value of the target pixel and the luminance values of second four neighboring pixels, and the target pixel and the second four neighboring pixels form an X shape; wherein the first luminance feature value is expressed as;
CV1=abs[Yr1+Yr2+Yr3+Yr4−
K1×
Yt],wherein CV1 is the first luminance feature value, Yt is the luminance value of the target pixel, Yr1, Yr2, Yr3, Yr4 are respectively the luminance values of the first four neighboring pixels that form the cross shape with the target pixel, K1 is a constant and abs is an absolute value operator. - View Dependent Claims (15, 16, 17, 18)
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Specification