Motion field generation for non-rigid image registration
First Claim
1. An apparatus for generating a motion field of an object when registering a first image of the object with a second image of the object, the apparatus comprising:
- a mesh grid generator configured to generate in the first image a mesh grid having a plurality of mesh nodes;
a nodal motion estimator configured to estimate, for each mesh node in the first image, at least one nodal motion vector that describes a matching of said mesh node with a corresponding mesh node in the second image; and
a motion field interpolator configured to determine a local motion vector for each of a plurality of points of interest within the first image, by interpolating from the nodal motion vectors of the mesh nodes that surround each point of interest in the first image.
9 Assignments
0 Petitions
Accused Products
Abstract
A method and system is presented for generating a full motion field of an object, when performing non-rigid image registration between a first and a second image of the object. A mesh grid generator generates in the first image a mesh grid having a plurality of mesh nodes, for each of a hierarchy of mesh resolution levels. A nodal motion estimator estimates, for each mesh node, at least one nodal motion vector that describes a matching of the mesh node with a corresponding mesh node in the second image. At each mesh node, multi-level block matching is performed, using a similarity measure based on pattern intensity. A smoothness constraint is imposed, in order to reconstruct the nodal motion vector for those mesh nodes at which mismatching occurs. A motion field interpolator determines a local motion vector for any desired point of interest within the first image, by interpolating from the nodal motion vectors of the surrounding mesh nodes.
92 Citations
72 Claims
-
1. An apparatus for generating a motion field of an object when registering a first image of the object with a second image of the object, the apparatus comprising:
-
a mesh grid generator configured to generate in the first image a mesh grid having a plurality of mesh nodes; a nodal motion estimator configured to estimate, for each mesh node in the first image, at least one nodal motion vector that describes a matching of said mesh node with a corresponding mesh node in the second image; and a motion field interpolator configured to determine a local motion vector for each of a plurality of points of interest within the first image, by interpolating from the nodal motion vectors of the mesh nodes that surround each point of interest in the first 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, 26, 27, 28, 29, 30, 31)
-
-
32. An apparatus for generating a motion field for an object when registering a first image of the object with a second image of the object, the apparatus comprising:
-
means for generating in the first image a mesh grid having a plurality of mesh nodes; means for estimating, for each mesh node in the first image, at least one nodal motion vector that describes a matching of said mesh node with a corresponding mesh node in the second image; means for reconstructing the nodal motion vector for a mesh node if a mismatch occurs between said mesh node and its corresponding mesh node; and means for determining a local motion vector for each of a plurality of points of interest within the first image, by interpolating from the nodal motion vectors of the mesh nodes that surround each point of interest in the first image.
-
-
33. An apparatus for generating a motion field representing a motion of an object between an acquisition of a first image of the object and an acquisition of a second image of the object, the apparatus comprising:
-
a nodal motion estimator configured to estimate, for each of a plurality of mesh nodes and at each of a plurality of mesh resolution levels, at least one nodal motion vector that describes a matching of each node in the first image with its corresponding mesh node in the second image; and a motion field interpolator configured to compute a local motion vector for each of a plurality of points of interest within the first image, by interpolating from the nodal motion vectors that are estimated at the final mesh resolution level for those mesh nodes that surround said point of interest. - View Dependent Claims (34)
-
-
35. An apparatus for generating a motion field representing a motion of an object between an acquisition of a first image of the object and an acquisition of a second image of the object, the apparatus comprising:
-
means for estimating, for each of a plurality of mesh nodes within the first image at each of a plurality of mesh resolution levels, at least one nodal motion vector that describes a matching of each node in the first image with its corresponding mesh node in the second image; and interpolation means for computing a local motion vector for each of a plurality of points of interest within the first image, by interpolating from the nodal motion vectors that are estimated, at a final one of said mesh resolution levels, for those mesh nodes that surround said point of interest.
-
-
36. An apparatus for determining a local motion vector for at least one point of interest within a first image of an object when registering the first image onto a second image of the object, the apparatus comprising:
-
a mesh grid generator configured to generate, for each of a plurality of mesh resolution levels, a mesh grid within the first image, said mesh grid having a plurality of mesh nodes; a nodal motion estimator configured to estimate, for each of said plurality of mesh resolution levels, at least one nodal motion vector for each mesh node in the first image, said nodal motion vector describing a matching of said mesh node onto a corresponding mesh node in the second image; and an interpolator configured to interpolate from the nodal motion vectors that are estimated for the mesh nodes that surround the at least one point of interest in the first image, so as to determine said local motion vector.
-
-
37. A computer-readable medium having stored therein computer-readable instructions for a processor, wherein the instructions, when read and implemented by the processor, cause the processor to:
-
input and store for a first image of an object data representative of a mesh grid having a plurality of mesh nodes, for each of a plurality of mesh resolution levels; estimate, for each mesh node in each mesh resolution level, at least one nodal motion vector that describes a matching of said mesh node onto a corresponding mesh node in a second image; and compute a local motion vector for one or more points of interest in the first image by interpolating from the nodal motion vectors estimated at a final mesh resolution level for the mesh nodes that surround each point of interest. - View Dependent Claims (38)
-
-
39. An apparatus for generating a motion field representing a motion of an object between an acquisition of a first image of the object and an acquisition of a second image of the object, the apparatus comprising:
a local motion determiner configured to determine a local motion vector for one or more points of interest within the first image by interpolating from nodal motion vectors estimated for a plurality of mesh nodes surrounding each point of interest within the first image.
-
40. A block matching system for performing multi-level block matching during image registration between a first image of an object and a second image of the object, the block matching system comprising:
-
means for defining a block centered around each of a plurality of mesh nodes that delineate a mesh grid in the first image; and means for attributing, to each mesh node, a matching mesh node in the second image that maximizes a similarity measure between said block in the first image and another block centered around the matching mesh node in the second image.
-
-
41. A method of generating a motion field for an object when registering a first image of the object with a second image of the object, the method comprising:
-
generating in the first image a mesh grid having a plurality of mesh nodes; for each mesh node in the first image, estimating at least one nodal motion vector that describes a matching of said mesh node with a corresponding mesh node in the second image; and determining a local motion vector for each of a plurality of points of interest within the first image, by interpolating from the nodal motion vectors of the mesh nodes that surround the point of interest in the first image. - View Dependent Claims (42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71)
-
-
72. A method of determining a local motion vector for at least one point of interest within a first image of an object when registering the first image onto a second image of the object, the method comprising:
-
A) for each of a plurality of mesh resolution levels, a) generating within the first image a mesh grid having a plurality of mesh nodes, the point of interest being located in the interior of the mesh grid; b) for each mesh node in the first image, estimating at least one nodal motion vector, the nodal motion vector describing a matching of said mesh node with a corresponding mesh node in the second image; and c) passing one or more estimated nodal motion vectors onto a subsequent mesh resolution level; and B) deriving the local motion vector at the point of interest by interpolating from the nodal motion vectors that have been estimated for the mesh nodes that surround the point of interest at a final one of said plurality of mesh resolution levels.
-
Specification