Method and apparatus for segmenting small structures in images
First Claim
1. A method for segmenting a small feature in a multidimensional digital array of intensity values in a data processor, the method comprising:
- computing an edge metric along each ray of a plurality of multidimensional rays originating at a local intensity extreme;
identifying a multidimensional edge point corresponding to a maximum edge metric on each said ray;
labeling every point on each said ray from said local intensity extreme to said edge point; and
labeling an unlabeled point if the unlabeled point is adjacent to a labeled point and the unlabeled paint point has a more extreme intensity than the labeled point and the unlabeled point is closer than the labeled point to the local intensity extreme.
2 Assignments
0 Petitions
Accused Products
Abstract
A method for segmenting a small feature in a multidimensional digital array of intensity values in a data processor computes an edge metric along each ray of a plurality of multidimensional rays originating at a local intensity extreme (local maximum or minimum). A multidimensional point corresponding to a maximum edge metric on each said ray is identified as a ray edge point. Every point on each ray from the local extreme to the ray edge point is labeled as part of the small object. Further points on the feature are grown by labeling an unlabeled point if the unlabeled point is adjacent to a labeled point, and the unlabeled point has a more extreme intensity than the labeled point, and the unlabeled point is closer than the labeled point to the local extreme. The resulting segmentation is quick, and identifies boundaries of small features analogous to boundaries identified by human analysts, and does not require statistical parameterizations or thresholds manually determined by a user.
-
Citations
51 Claims
-
1. A method for segmenting a small feature in a multidimensional digital array of intensity values in a data processor, the method comprising:
-
computing an edge metric along each ray of a plurality of multidimensional rays originating at a local intensity extreme; identifying a multidimensional edge point corresponding to a maximum edge metric on each said ray; labeling every point on each said ray from said local intensity extreme to said edge point; and labeling an unlabeled point if the unlabeled point is adjacent to a labeled point and the unlabeled paint point has a more extreme intensity than the labeled point and the unlabeled point is closer than the labeled point to the local intensity extreme. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
-
-
18. A method for segmenting a small feature in a multidimensional digital array of intensity values in a dataprocessor, the method comprising:
-
computing an edge metric along each ray of plurality of multidimensional rays originating at a local intensity extreme;
;
identifying a multidimensional edge point corresponding to a maximum edge metric on each said ray;
;
labeling every point on each said ray from said local intensity extreme to said edge point; labeling an unlabeled point if the unlabeled point is adjacent to a Labeled labeled point and the unlabeled point has a more extreme intensity than the labeled point and the unlabeled point is closer than the labeled point to the local intensity extreme;
;
andadditionally labeling an unlabeled point if the unlabeled point is adjacent to a labeled point and has a more extreme intensity than the labeled point and is no farther from the local intensity extreme than the sum of a distance from the labeled point to the local intensity extreme plus an expansive tolerance distance less than the spacing between adjacent points;
whereinan expected size of a small feature is twice an integral number N times a spacing distance between adjacent points in the array, N is greater than 1, the maximum value of the difference in distances between the labeled point and the unlabeled point to the local intensity extreme (Gmax)=−
N+√
{square root over (N2+2))}, andthe expansive tolerance distance is less than about Gmax.
-
-
19. A data processing apparatus for segmenting a small feature in a multidimensional digital array of intensity values comprising:
-
an input for a plurality of intensity values arranged along regular increments in each of a plurality of dimensions; a memory medium for storing the plurality of intensity values as a multidimensional digital array; a processor configured to detect a local intensity extreme in the multidimensional digital array, to identify points along a plurality of rays originating at the total local intensity extreme, to identify one edge point on each ray of said plurality of rays, said edge point associated with a maximum edge metric along said ray, to label each point on each ray from the local intensity extreme to the edge point, and to label an unlabeled point adjacent to a labeled point if the unlabeled point has a more extreme intensity than the labeled point and the unlabeled point is closer than the labeled point to the local intensity extreme until no more unlabeled points can be labeled; and an output for providing the labeled points for subsequent processing. - View Dependent Claims (20, 21)
-
-
22. A computer program embodied in a non-transitory computer readable medium for performing the steps of:
computing an edge metric along each ray of a plurality of multidimensional rays originating at a local intensity extreme, identifying a multidimensional edge point corresponding to a maximum edge metric on each said ray, labeling every point on each said ray from said local intensity extreme to said edge point, and labeling an unlabeled point if the unlabeled point is adjacent to a labeled point and the unlabeled point has a more extreme intensity than the labeled point and the unlabeled point is closer than the labeled point to the local intensity extreme.
-
23. A method of labeling pixels of an image so as to designate portions of the image that are associated with an object, the method comprising:
-
identifying a first pixel as belonging to an object due to the first pixel having an intensity that is a local intensity extreme, wherein the first pixel is at an interior of the object; determining that a second pixel that lies on a ray that emanates from the first pixel has a maximum edge metric on the ray, wherein the second pixel has an intensity that is smaller in magnitude than the intensity of the first pixel; labeling the second pixel as an edge pixel that lies on an edge of the object; determining that a third pixel that is adjacent to the second pixel satisfies a predetermined criterion relative to one or more of the first and second pixels; and labeling the third pixel as belonging to the object. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
-
-
37. A method of labeling a subset of pixels of an image, the method comprising:
-
labeling pixels of an image as belonging to a first object that is encompassed by a first edge; labeling pixels of the image as belonging to a second object that is encompassed by a second edge; and assembling the first and second objects into a third object that is larger than either of the first and second objects if a distance between the first and second edges is no more than a join distance. - View Dependent Claims (38, 39)
-
-
40. A non-transitory computer-readable medium having instructions stored thereon, the instructions comprising:
-
instructions for labeling pixels of an image as belonging to a first object that is encompassed by a first edge; instructions for labeling pixels of the image as belonging to a second object that is encompassed by a second edge; and instructions for assembling the first and second objects into a third object that is larger than either of the first and second objects if a distance between the first and second edges is no more than a join distance.
-
-
41. A method of labeling pixels of an image so as to designate portions of the image that are associated with an object, the method comprising:
-
identifying a first pixel as belonging to an object due to the first pixel having an intensity that is a local intensity extreme, wherein the first pixel is spaced from an edge of the object; identifying as belonging to the object a second pixel that lies on a first substantially straight line on which the first pixel also lies; identifying a third pixel as belonging to the object after having identified the second pixel as belonging to the object, wherein the third pixel lies on the line at a position that is closer to the first pixel than is the second pixel; and labeling each of the first, second, and third pixels as belonging to the object. - View Dependent Claims (42, 43, 44, 45, 46, 47, 48, 49)
-
-
50. A non-transitory computer-readable medium having instructions stored thereon, the instructions comprising:
-
instructions for identifying a first pixel as belonging to an object due to the first pixel having an intensity that is a local intensity extreme, wherein the first pixel is spaced from an edge of the object; instructions for identifying as belonging to the object a second pixel that lies on a first substantially straight line on which the first pixel also lies; instructions for identifying a third pixel as belonging to the object after having identified the second pixel as belonging to the object, wherein the third pixel lies on the line at a position that is closer to the first pixel than is the second pixel; and instructions for labeling each of the first, second, and third pixels as belonging to the object.
-
-
51. A non-transitory computer-readable medium having instructions stored thereon, the instructions comprising:
-
instructions for identifying a first pixel as belonging to an object due to the first pixel having an intensity that is a local intensity extreme, wherein the first pixel is at an interior of the object; instructions for determining that a second pixel that lies on a ray that emanates from the first pixel has a maximum edge metric on the ray, wherein the second pixel has an intensity that is smaller in magnitude than the intensity of the first pixel; instructions for labeling the second pixel as an edge pixel that lies on an edge of the object; instructions for determining that a third pixel that is adjacent to the second pixel satisfies a predetermined criterion relative to one or more of the first and second pixels; and instructions for labeling the third pixel as belonging to the object.
-
Specification