Method and apparatus for registration of an atlas to an image

• US 8,687,917 B2
• Filed: 05/02/2006
• Issued: 04/01/2014
• Est. Priority Date: 05/02/2005
• Status: Expired due to Fees

• Current Assignee: Agency For Science Technology and Research (Government of Singapore)
• Original Assignee: Agency For Science Technology and Research (Government of Singapore)
• Inventors: Liu, Jimin, Huang, Su, Nowinski, Wieslaw Lucjan
• Primary Examiner(s): ENTEZARI, MICHELLE M
• Application Number:
  US11/919,833
• Publication Number:
  US 20090220171A1
• Time in Patent Office: 2,891 Days
• Field of Search: None
• US Class Current: 382/282
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: A61B 6/501 for diagnosis of the head, e.g. neuroimaging or craniography
• CPC Class Codes: A61B 6/5247 combining images from an ionising-radiation diagnostic technique and a non-ionising radiation diagnostic technique, e.g. X-ray and ultrasound
• CPC Class Codes: G06T 2207/30016 Brain
• CPC Class Codes: G06T 7/33 using feature-based methods
• CPC Class Codes: G06V 10/754 involving a deformation of the sample pattern or of the reference pattern; Elastic matching
• CPC Class Codes: G06V 20/653 by matching three-dimensional models, e.g. conformal mapping of Riemann surfaces

Abstract

A method (100) and an apparatus (200) are disclosed for registering an input image and an atlas. The atlas is warped (130) using non-rigid registration. In particular, boundary displacements of structures in the atlas are calculated (132) which register those structures with equivalent structures in the input image. The boundaries of structures in the atlas are then warped (133) according to their respective boundary displacements using topology preserving propagation of boundary points of the structures.

Claims

1. A method of non-rigidly registering an atlas with an image, said method comprising the steps of:

dividing a predefined domain into regular blocks, said regular blocks being hexahedrons, said atlas and said image being volumetric images defined in said predefined domain, said atlas comprising a plurality of labels L, each non-zero label L representing a labeled structure and the label L=0 representing an unlabeled structure;

calculating a boundary displacement of at least one structure in said atlas according to labels L of that structure to register that structure with an equivalent structure in said image, said calculating step comprising the sub-steps of;

calculating a displacement of centre points of each block, said displacement maximising a block similarity measure between corresponding blocks in said atlas and said image; and

calculating said boundary displacement by calculating a displacement for points on said boundary of said structure by interpolating said displacements of neighbouring centre points; and

warping the boundary of said structure in said atlas according to said boundary displacement using topology preserving front propagation of boundary points of said structure in said atlas according to labels L.

2. The method according to claim 1, wherein said topology preserving propagation of boundary points comprises adding points to and removing points from the boundary of said structure.

3. The method according to claim 2, wherein only points not belonging to other structures are added to said structure.

10. The method according to claim 1, further comprising:

pre-processing said image to remove features in said image that are not part of the object modelled in said atlas; and

aligning said atlas roughly to said image using a global affine transformation.

11. The method according to claim 1, wherein said atlas is a brain atlas, and said image is obtained using magnetic resonance imaging (MRI).

4. An apparatus for non-rigidly registering an atlas with an image, said apparatus comprising:

means for dividing a predefined domain into regular blocks, said regular blocks being hexahedrons, said atlas and said image being volumetric images defined in said predefined domain, said atlas comprising a plurality of labels L, each non-zero label L representing a labeled structure and the label L=0 representing an unlabeled structure;

means for calculating a boundary displacement of at least one structure in said atlas to register that structure with an equivalent structure in said image, said calculating means comprising;

means for calculating a displacement of centre points of each block, said displacement maximising a block similarity measure between corresponding blocks in said atlas and said image; and

means for calculating said boundary displacement by calculating a displacement for points on said boundary of said structure by interpolating said displacements of neighbouring centre points; and

means for warping the boundary of said structure in said atlas according to said boundary displacement using topology preserving front propagation of boundary points of said structure in said atlas according to labels L.

5. The apparatus according to claim 4, wherein said topology preserving propagation of boundary points comprises adding points to and removing points from the boundary of said structure.

6. The apparatus according to claim 5, wherein only points not belonging to other structures are added to said structure.

12. The apparatus according to claim 4, further comprising:

means for pre-processing said image to remove features in said image that are not part of the object modelled in said atlas; and

means for aligning said atlas roughly to said image using a global affine transformation.

13. The apparatus according to claim 4, wherein said atlas is a brain atlas, and said image is obtained using magnetic resonance imaging (MRI).

7. A computer program product including a non-transitory computer readable medium having recorded thereon a computer program for execution on a computer system for non-rigidly registering an atlas with an image, said computer program comprising:

code for dividing a predefined domain into regular blocks, said regular blocks being hexahedrons, said atlas and said image being volumetric images defined in said predefined domain, said atlas comprising a plurality of labels L, each non-zero label L representing a labeled structure and the label L=0 representing an unlabeled structure;

code for calculating a boundary displacement of at least one structure in said atlas to register that structure with an equivalent structure in said image, said calculating code comprising;

code for calculating a displacement of centre points of each block, said displacement maximising a block similarity measure between corresponding blocks in said atlas and said image; and

code for calculating said boundary displacement by calculating a displacement for points on said boundary of said structure by interpolating said displacements of neighbouring centre points; and

code for warping the boundary of said structure in said atlas according to said boundary displacement using topology preserving propagation of boundary points of said structure.

8. The computer program product according to claim 7, wherein said topology preserving propagation of boundary points comprises adding points to and removing points from the boundary of said structure.

9. The computer program product according to claim 8, wherein only points not belonging to other structures are added to said structure.

14. The computer program product according to claim 7, further comprising:

code for pre-processing said image to remove features in said image that are not part of the object modelled in said atlas; and

code for aligning said atlas roughly to said image using a global affine transformation.

15. The computer program product according to claim 7, wherein said atlas is a brain atlas, and said image is obtained using magnetic resonance imaging (MRI).