Breast Skin Line Detection in Radiographic Images
First Claim
1. A method for segmenting an image comprising pixels, the method comprising:
- applying a second derivative operator to the pixels to derive first and second eigenvalues and an orientation angle for each of the pixels;
generating a seeding grid comprising an array of a subset of the pixels;
growing a set of contours using the subset of pixels as potential contour starting points;
pruning the set of contours to generate a pruned set of contours;
determining a contour strength vector for each of the contour pixels based on a maximum positive one of the eigenvalues and the orientation angle of the respective contour pixel;
generating a partial ellipse representing an estimated location of an object in the image by combining the contour strength vectors with a set of directional operators;
dividing the partial ellipse into a plurality of support sectors, each sector including a respective control point on the partial ellipse;
for each of the pruned contours centered in a respective sector, setting a contour strength to be a maximum of dot products of the respective contour strength vectors with a normal to the partial ellipse at the respective sector'"'"'s control point, and setting a contour position to be a location of the maximum product;
adjusting a position of each sector control point based on the contour positions weighted by the contour strengths of the pruned contours centered in the respective sector;
fitting the partial ellipse to the adjusted positions of the control points to generate a partial fitted ellipse; and
generating a segmentation mask of the object based on the partial fitted ellipse.
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Abstract
An image segmentation embodiment comprises applying a second derivative operator to the pixels of an image, growing a set of contours using seeding grid points as potential contour starting points, determining a contour strength vector for each of the contour pixels, generating a partial ellipse representing an estimated location of an object in the image, dividing the partial ellipse into a plurality of support sectors with control points, determining a contour strength and position for each contour, adjusting a position of each sector control point based on the contour positions weighted by the contour strengths of the contours centered in the respective sector, fitting the partial ellipse to the adjusted positions of the control points, and generating a segmentation mask of the object based on the partial fitted ellipse.
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Citations
21 Claims
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1. A method for segmenting an image comprising pixels, the method comprising:
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applying a second derivative operator to the pixels to derive first and second eigenvalues and an orientation angle for each of the pixels; generating a seeding grid comprising an array of a subset of the pixels; growing a set of contours using the subset of pixels as potential contour starting points; pruning the set of contours to generate a pruned set of contours; determining a contour strength vector for each of the contour pixels based on a maximum positive one of the eigenvalues and the orientation angle of the respective contour pixel; generating a partial ellipse representing an estimated location of an object in the image by combining the contour strength vectors with a set of directional operators; dividing the partial ellipse into a plurality of support sectors, each sector including a respective control point on the partial ellipse; for each of the pruned contours centered in a respective sector, setting a contour strength to be a maximum of dot products of the respective contour strength vectors with a normal to the partial ellipse at the respective sector'"'"'s control point, and setting a contour position to be a location of the maximum product; adjusting a position of each sector control point based on the contour positions weighted by the contour strengths of the pruned contours centered in the respective sector; fitting the partial ellipse to the adjusted positions of the control points to generate a partial fitted ellipse; and generating a segmentation mask of the object based on the partial fitted ellipse. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A system for segmenting an image comprising pixels, the system comprising:
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a curvature image generator applying a second derivative operator to the pixels to derive first and second eigenvalues and an orientation angle for each of the pixels; a seeding grid generator generating a seeding grid comprising an array of a subset of the pixels; a contour generator growing a set of contours using the subset of pixels as potential contour starting points; a contour pruner pruning the set of contours to generate a pruned set of contours; a vector generator determining a contour strength vector for each of the contour pixels based on a maximum positive one of the eigenvalues and the orientation angle of the respective contour pixel; an ellipse generator generating a partial ellipse representing an estimated location of an object in the image by combining the contour strength vectors with a set of directional operators; a sector divider dividing the partial ellipse into a plurality of support sectors, each sector including a respective control point on the partial ellipse; a contour strength detector setting, for each of the pruned contours centered in a respective sector, a contour strength to be a maximum of dot products of the respective contour strength vectors with a normal to the partial ellipse at the respective sector'"'"'s control point, and setting, for each of the pruned contours centered in the respective sector, a contour position to be a location of the maximum product; a control point adjuster adjusting a position of each sector control point based on the contour positions weighted by the contour strengths of the pruned contours centered in the respective sector; an ellipse adjuster fitting the partial ellipse to the adjusted positions of the control points to generate a partial fitted ellipse; and a segmentation mask generator generating a segmentation mask of the object based on the partial fitted ellipse.
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12. A computer program product for segmenting an image, the computer program product having a non-transitory computer-readable medium with a computer program embodied thereon, the computer program comprising:
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computer program code for applying a second derivative operator to the pixels to derive first and second eigenvalues and an orientation angle for each of the pixels; computer program code for generating a seeding grid comprising an array of a subset of the pixels; computer program code for growing a set of contours using the subset of pixels as potential contour starting points; computer program code for pruning the set of contours to generate a pruned set of contours; computer program code for determining a contour strength vector for each of the contour pixels based on a maximum positive one of the eigenvalues and the orientation angle of the respective contour pixel; computer program code for generating a partial ellipse representing an estimated location of an object in the image by combining the contour strength vectors with a set of directional operators; computer program code for dividing the partial ellipse into a plurality of support sectors, each sector including a respective control point on the partial ellipse; computer program code for setting, for each of the pruned contours centered in a respective sector, a contour strength to be a maximum of dot products of the respective contour strength vectors with a normal to the partial ellipse at the respective sector'"'"'s control point, and for setting, for each of the pruned contours centered in a respective sector, a contour position to be a location of the maximum product; computer program code for adjusting a position of each sector control point based on the contour positions weighted by the contour strengths of the pruned contours centered in the respective sector; computer program code for fitting the partial ellipse to the adjusted positions of the control points to generate a partial fitted ellipse; and computer program code for generating a segmentation mask of the object based on the partial fitted ellipse. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification