Method and system for detecting small structures in images
First Claim
1. A method for detecting a structure in an image, the method comprising the steps of:
- digitizing the image;
storing the digitized image in a memory of a data processing means;
detecting automatically the structure using the data processing means and the digitized image comprising the steps of;
segmenting the digitized image into a candidate structure to be classified;
extracting features from the candidate structure;
characterizing the candidate structure using the features; and
classifying the candidate structure, using the extracted features, as structure or as background; and
indicating the location of the structure in the image.
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Abstract
The invention is a method and apparatus for automated detection of small structures in images. One specific use is to detect malignant microcalcification clusters in mammograms. A digitized and filtered mammogram image is stored in a computer. Seed pixels, which are pixels that are brighter than their immediate neighbors, are identified to indicate candidate structures and used to construct two regions. Various features are then measured using the two regions around each seed point. The features characterize each candidate structure and are input to a classifier, such as a neural network. The classifier then distinguishes between structures of interest and background. The structures detected by the classifier are then presented to a clustering algorithm. A detected structure that is less than a threshold distance away from the nearest structure and a cluster is included in that cluster. Finally, the results are displayed, either on a monitor or on hard copy, with a frame around the detected cluster.
7 Citations
26 Claims
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1. A method for detecting a structure in an image, the method comprising the steps of:
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digitizing the image;
storing the digitized image in a memory of a data processing means;
detecting automatically the structure using the data processing means and the digitized image comprising the steps of;
segmenting the digitized image into a candidate structure to be classified;
extracting features from the candidate structure;
characterizing the candidate structure using the features; and
classifying the candidate structure, using the extracted features, as structure or as background; and
indicating the location of the structure in the image. - View Dependent Claims (2, 3, 4, 5)
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7. The method as recited in
claim 7 , the extracting features step comprising the step of measuring a gray level value of the seed pixel (sv).
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8. The method as recited in
claim 8 , the extracting features step further comprising the step of measuring a gray level value of the seed pixel (sv).
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10. The method as recited in
claim 10 , the extracting features step further comprising the step of measuring an area of the first region in pixels (a1).
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12. The method as recited in
claim 12 , the extracting features step further comprising the step of measuring an area of the second region in pixels (a2).
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14. The method as recited in
claim 14 , the extracting features step further comprising the step of measuring a local contrast obtained by subtracting the mean value of pixels along the edge of the first region from the seed pixel value (ac1).
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16. The method as recited in
claim 16 , the extracting features step further comprising the step of measuring a local contrast obtained by subtracting the mean value of pixels along the edge of the second region from the seed pixel value (ac2).
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18. The method as recited in
claim 18 , the extracting features step further comprising the step of measuring the mean value of the higher fifty percentile of the gradient values of the pixels along the edge of the first region (mxs1).
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20. The method as recited in
claim 20 , the extracting features step further comprising the step of measuring the mean value of the higher fifty percentile of the gray level differences between the seed pixel value and each pixel along the edge of the second region (mxc2) 23.
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22. The method as recited in
claim 22 , the extracting features step further comprising the step of measuring the mean angle index of the structure (aa).
- 26. The method as recited in claim 27, wherein the image is a mammogram and the structure is a microcalcification.
Specification