Method and system for automated detection of microcalcification clusters in mammograms
First Claim
Patent Images
1. A method of operating an image interpretation system wherein an object in the image is automatically detected, the method comprising the steps of:
- digitizing the image;
inputting the digitized image into a data processing means;
detecting automatically the object using the data processing means and the digitized image comprising the steps of;
forming a contour plot of the image, the object in the contour plot comprised of a set of nested contour lines wherein the contour lines correspond to intensity levels thereby causing the object to appear as a peak in relation to the surrounding background in the image;
obtaining a sequence of contour areas from the set of nested contour lines progressing from the contour line having the highest intensity level to the contour line having the lowest intensity level;
computing a feature of the set of nested contour lines using the sequence of contour areas; and
detecting the object using the computed feature; and
indicating the location of the object in the image.
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Abstract
The invention is a novel method for automated detection of objects in images. One specific use is to detect malignant microcalcification clusters in mammograms. The method operates by forming a contour plot of the image (mammogram), the object (microcalcification) in the contour plot being comprised of a set of nested contour lines wherein the contour lines correspond to intensity levels thereby causing the object to appear as a prominent peak in relation to the local surround in the image.
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Citations
35 Claims
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1. A method of operating an image interpretation system wherein an object in the image is automatically detected, the method comprising the steps of:
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digitizing the image; inputting the digitized image into a data processing means;
detecting automatically the object using the data processing means and the digitized image comprising the steps of;forming a contour plot of the image, the object in the contour plot comprised of a set of nested contour lines wherein the contour lines correspond to intensity levels thereby causing the object to appear as a peak in relation to the surrounding background in the image; obtaining a sequence of contour areas from the set of nested contour lines progressing from the contour line having the highest intensity level to the contour line having the lowest intensity level; computing a feature of the set of nested contour lines using the sequence of contour areas; and detecting the object using the computed feature; and indicating the location of the object in the image. - 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. A method of operating a mammogram interpretation system wherein a microcalcification in the mammogram is automatically detected, the method comprising the steps of:
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digitizing the mammogram; inputting the digitized mammogram into a data processing means; detecting automatically the microcalcification using the data processing means and the digitized mammogram comprising the steps of; forming a contour plot of the mammogram, the microcalcification in the contour plot comprised of a set of nested contour lines wherein each contour line is formed of pixels having intensity values equal to or higher than the intensity level of the contour line thereby causing the microcalcification to appear as a prominent peak in relation to the surrounding background in the mammogram; obtaining a sequence of contour areas from the set of nested contour lines progressing from the contour line having the highest intensity level to the contour line having the lowest intensity level; computing a value for the departure of the peak from the surrounding background in the mammogram by computing the rate of change of the sequence of contour areas as the sequence approaches the contour line having the lowest intensity level, wherein the departure value is set to the highest relative increase in the first difference sequence of contour areas and the corresponding intensity level is the departure level; computing the prominence of the peak, the prominence being an integer equal to the number of contour lines above the departure level; computing the steepness of the peak comprising the steps of; computing a ratio of change in grey value to change in area with increasing contour lines at each level above the departure level; and setting the steepness to the mean of the ratios; and detecting a microcalcification cluster of three microcalcifications when three or more peaks occur in an area of about 1 cm2 and have values of departure, prominence and steepness that fall in the corresponding acceptance range; and indicating the location of the microcalcification cluster in the mammogram.
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27. An image interpretation system wherein an object in the image is automatically detected, the system comprising:
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means for digitizing the image; a data processing means for receiving the digitized image; means for automatically detecting the object using the data processing means and the digitized image, the automatic detection means comprising; means for forming a contour plot of the image, the object in the contour plot comprised of a set of nested contour lines wherein the contour lines correspond to intensity levels thereby causing the object to appear as a peak in relation to the surrounding background in the image; means for obtaining a sequence of contour areas from the set of nested contour lines progressing from the contour line having the highest intensity level to the contour line having the lowest intensity level; means for computing a feature of the set of nested contour lines using the sequence of contour areas; and means for detecting the object using the computed feature; and means for indicating the location of the object in the image. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34)
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35. An mammogram interpretation system wherein a microcalcification in the mammogram is automatically detected, the system comprising:
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means for digitizing the mammogram; a data processing means for receiving the digitized mammogram; means for automatically detecting the microcalcification using the data processing means and the digitized mammogram, the automatic detection means comprising; means for forming a contour plot of the mammogram, the microcalcification in the contour plot comprised of a set of nested contour lines wherein each contour line is formed of pixels having intensity values equal to or higher than the intensity level of the contour line thereby causing the microcalcification to appear as a prominent peak in relation to the surrounding background in the mammogram; means for obtaining a sequence of contour areas from the set of nested contour lines progressing from the contour line having the highest intensity level to the contour line having the lowest intensity level; means for computing a value for the departure of the peak from the surrounding background in the mammogram by computing the rate of change of the sequence of contour areas as the sequence approaches the contour line having the lowest intensity level, wherein the departure value is set to the highest relative increase in the first difference sequence of contour areas and the corresponding intensity level in the departure level; means for computing the prominence of the peak, the prominence being an integer equal to the number of contour lines above the departure level; means for computing the steepness of the peak comprising; means for computing a ratio of change in grey value to change in area with increasing contour lines at each level above the departure level; and means for setting the steepness to the mean of the ratios; and means for detecting a microcalcification cluster of three microcalcifications when three or more peaks occur in an area of about 1 cm2 and have values of departure, prominence and steepness that fall in the corresponding acceptance range; and means for indicating the location of the microcalcification cluster in the mammogram.
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Specification