Image processing method for removing noise from an image
First Claim
1. An image processing method for removing noise contained in an image, comprising:
- inputting an original image constituted with a plurality of pixels;
extracting a first high-frequency component through first high-pass filter processing executed on the original image;
extracting a second high-frequency component through second high-pass filter processing executed on the extracted first high-frequency component;
extracting a noise component by separating the noise component through nonlinear conversion processing executed on the extracted second high-frequency component; and
removing noise in the original image based upon the extracted noise component, whereinthe nonlinear conversion processing is attenuation processing whereby a non-noise component contained in the second high-frequency component is attenuated by multiplying the second high-frequency component by a weighted Gaussian coefficient having an argument of a value resulting from a comparison of the second high-frequency component with a predetermined threshold value.
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Abstract
An image processing method for removing noise contained in an image includes: inputting an original image constituted with a plurality of pixels; generating a plurality of band-limited images, resolution levels of which are lowered in sequence, by executing a specific type of band pass filter processing on the original image; extracting a high-frequency component from each of the band-limited images by executing high-pass filter processing on the band-limited images; extracting a noise component contained in each of the band-limited images by separating the noise component through nonlinear conversion processing executed on the extracted high-frequency component; and removing the noise in the original image based upon the extracted noise component in each band-limited image.
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Citations
10 Claims
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1. An image processing method for removing noise contained in an image, comprising:
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inputting an original image constituted with a plurality of pixels; extracting a first high-frequency component through first high-pass filter processing executed on the original image; extracting a second high-frequency component through second high-pass filter processing executed on the extracted first high-frequency component; extracting a noise component by separating the noise component through nonlinear conversion processing executed on the extracted second high-frequency component; and removing noise in the original image based upon the extracted noise component, wherein the nonlinear conversion processing is attenuation processing whereby a non-noise component contained in the second high-frequency component is attenuated by multiplying the second high-frequency component by a weighted Gaussian coefficient having an argument of a value resulting from a comparison of the second high-frequency component with a predetermined threshold value. - View Dependent Claims (2, 3, 4, 5, 8, 9, 10)
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6. An image processing method for removing noise contained in an image, comprising:
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obtaining the image; and performing a processing operation on the image, comprising; extracting a first high-frequency component by applying a high-pass filter to the obtained image; extracting a noise component from the extracted first high-frequency component through non-linear conversion; subtracting the extracted noise component from the image; extracting a second high-frequency component from the image from which the noise component has been subtracted, by applying the high-pass filter with the same characteristics as in the extraction of the first high-frequency component; extracting a correction component from the second high-frequency component through non-linear conversion having the same characteristics used in the extraction of the noise component; and adding the extracted correction component to the image from which the noise component has been subtracted to generate a resultant image, wherein the processing operation is repeated at least once, in which each repetition comprises performing the processing operation on the resultant image of a previous processing operation, the nonlinear conversion processing in the extraction of both the noise and the correction component is attenuation processing whereby a non-noise component contained in the first high-frequency component is attenuated by multiplying the first high-frequency component by a weighted Gaussian coefficient having an argument of a value resulting from a comparison of the first high-frequency component with a predetermined threshold value, and an edge component corresponding to overcorrection contained in the second high frequency component is attenuated by multiplying the second high frequency component by another weighted Gaussian coefficient having an argument of a value resulting from a comparison of the second high-frequency component with the identical threshold value as defined in the noise extraction processing. - View Dependent Claims (7)
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Specification