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EP0609922A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Computer detection of microcalcifications in mammograms

Assignee: Koninklijke Philips NV
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Filing: 1994-01-05
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Granted: —
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Expires: 2014-01-05
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Abstract

Abstract A method of aiding detection of breast cancer by computer analysis of a mammogram image includes computing filtered second spatial derivative of intensity values at the pixels of the image, in the form of a Laplacian. The filtering is iterative adaptive smoothing of the first spatial derivative, which smoothing is applied to achieve relatively great smoothing effect where there is relatively little local variation in derivative value and a relatively small or no smoothing effect where there is relatively great local variation in derivative value. This has the effect of preserving locations of zero crossings in the Laplacian which correspond to edges or boundaries in the image. Regions of negative Laplacian value are labelled and connected. These labelled regions are locally bright spots in the image. From the preserved boundary locations of these locally bright spots, a plurality of feature measures are computed, indicative of their respective brightnesses, shapes and edge contrasts. Those locally bright spots having a weighted combination of logarithms of these feature measures exceeding a predetermined value are identified as microcalcifications of a type associated with cancer, and it is detected where such identified microcalcifications are grouped in clusters.

Inventors

  • 👤 Charles Spencer C/O Int. Octrooibureau Bv Carman

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-09 14:04
CPC Classifications
G; G06; G06T; G06T7/00; G06T7/0002; G06T7/0012; G16; G16H; G16H15/00; G06T2207/00; G06T2207/30; G06T2207/30004; G06T2207/30068; G16H30/00; G16H30/20

Claims Analysis

Total Claims: 5
Claim 1
Independent Claim 126 words
A method for the detection of objects of a predetermined type in an image stored as a two-dimensional array of pixel positions with respective digitized intensity values, the method comprising computing filtered second spatial derivative of intensity values for pixel positions of the image, in a manner which preserves the locations of edges of any spots in said image different in intensity from their surroundings as zero crossings in values of said second derivative; computing a plurality of measures of features of one or more identified spots, said plurality of measures being indicative of at least shape and edge gradient of said spots; and based on a determination from said measures of features computed, identifying which of said spots correspond to objects of said predetermined type.
Claim 2
Independent Claim 155 words
A method for aiding detection of cancer, comprising: generating a radiologic image of a region of human anatomy, said image comprising a two dimensional array of pixel positions having respective digitized intensity values; storing said image in a digital storage device; and automatically performing the following steps with a computer having access to the storage device: computing filtered second spatial derivative of intensity values for pixel positions of the radiologic image, in a manner which preserves the locations of edges of any spots in said image different in intensity from their surrounds as zero crossings in values of said second derivative; computing a plurality of measures of features of one or more identified spots, said plurality of measures being indicative of at least shape and edge gradient of said spots; and based on a determination from said measures of features computed, identifying which of said spots correspond to objects of a type associated with malignancy.
Claim 3
Dependent Claim 64 words
The cancer detection aiding method as claimed in Claim 1, wherein said radiologic image is a mammogram and said objects are microcalcifications, said method further comprising: identifying one or more clusters of said spots identified as corresponding to microcalcifications of a type associated with malignancy; and providing a human intelligible indication of location in the radiologic image of said identified one or more clusters.
Claim 4
Dependent Claim 159 words
The cancer detection aiding method as claimed in Claim 2 or 3, wherein said filtered second derivative is computed as follows: computing first spatial derivative of intensity values at pixel positions in said radiologic image; iteratively adaptive smoothing the first spatial derivative values in a manner that an adaptive smoothed first derivative value for a considered pixel position is arrived at by adaptive weighting first derivative values at adjoining pixel positions to achieve a relatively great smoothing effect when such adjoining pixel positions have first spatial derivative values which are relatively similar to the first spatial derivative value of the considered pixel position and to achieve relatively little or no smoothing effect when such adjoining pixel positions have first spatial derivative values which are relatively different from the first spatial derivative value at the considered pixel position; and computing spatial derivative values of the adaptive smoothed first spatial derivative values to form filtered second spatial derivative of intensity values.
Claim 5
Independent Claim 175 words
A device for assisting the detection of objects of a predetermined type in an image, the device comprising a memory for the storage of the image as a two-dimensional array of pixel positions with respective digitized intensity values, display means for the display of said image and of human intelligible indication on said image and processing means having access to said memory and said display, the processing means being arranged for computing filtered second spatial derivative of intensity values for pixels of the image stored in said memory in a manner which preserves the locations of edges of any spots in said image different in intensity from their surroundings as zero crossings in values of said second derivative; computing a plurality of measures of features of identified one or more spots, said plurality of measures being indicative of at least shape and edge gradient of said spots; and based on a determination from said measures of features computed, identifying and indicating on said display which of said spots correspond to objects of said predetermined type.

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