Image processing method and X-ray CT system
First Claim
1. An image processing method comprising the steps of:
- wavelet-transforming an input image using a gradient form;
classifying resultant wavelet vectors into categories of strongly edged objects, weakly edged objects, radial lines, and noises;
leaving the wavelet vectors, which are classified into the category of strongly edged objects, intact;
filtering the directions of the wavelet vectors classified into the category of weakly edged objects;
smoothing the wavelet vectors classified into the categories of radial lines and noises; and
inverse-wavelet-transforming the resultant wavelet vectors so as to produce an output image.
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Abstract
An object of the present invention is to provide an image processing method for reducing noises without causing a side effect and an X-ray CT system that performs the image processing. An input image is wavelet-transformed using a gradient form. Resultant wavelet vectors are classified into categories of strongly edged objects, weakly edged objects, radial lines, and noises. The wavelet vectors classified into the category of strongly edged object are left intact. The wavelet vectors classified into the category of weakly edged objects have the directions thereof filtered. The wavelet vectors classified into the categories of radial lines and noises are smoothed. The resultant wavelet vectors are inverse-wavelet-transformed in order to produce an output image.
7 Citations
10 Claims
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1. An image processing method comprising the steps of:
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wavelet-transforming an input image using a gradient form; classifying resultant wavelet vectors into categories of strongly edged objects, weakly edged objects, radial lines, and noises; leaving the wavelet vectors, which are classified into the category of strongly edged objects, intact; filtering the directions of the wavelet vectors classified into the category of weakly edged objects; smoothing the wavelet vectors classified into the categories of radial lines and noises; and inverse-wavelet-transforming the resultant wavelet vectors so as to produce an output image. - View Dependent Claims (2, 3, 4, 5)
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6. An X-ray CT system comprising a data acquisition means for acquiring data by scanning a subject with X-rays, an image reconstruction means for reconstructing an image on the basis of the acquired data, and an image processing means for processing the reconstructed image, wherein:
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the image processing means comprises; a transforming means for wavelet-transforming an input image using a gradient form; a classifying means for classifying resultant wavelet vectors into categories of strongly edged objects, weakly edged objects, radial lines, and noises; leaving the wavelet vectors, which are classified into the category of strongly edged objects, intact; filtering the directions of the wavelet vectors classified into the category of weakly edged objects; smoothing the wavelet vectors classified into the categories of radial lines and noises; and inverse-wavelet-transforming the resultant wavelet vectors so as to produce an output image. - View Dependent Claims (7, 8, 9, 10)
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Specification