Method and apparatus for optimally matching data sets

• US 7,616,835 B2
• Filed: 03/15/2004
• Issued: 11/10/2009
• Est. Priority Date: 03/18/2003
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Lobregt, Steven
• Primary Examiner(s): Mehta; Bhavesh M
• Assistant Examiner(s): Vanchy, Jr.; Michael
• Application Number:
  US10/548,965
• Publication Number:
  US 20060285771A1
• Time in Patent Office: 2,066 Days
• Field of Search: 382/294
• US Class Current: 382/294
• CPC Class Codes: G06T 3/14 Transformations for image registration, e.g. adjusting or mapping for alignment of images
• CPC Class Codes: G06T 7/30 Determination of transform parameters for the alignment of images, i.e. image registration
• CPC Class Codes: G06V 10/42 Global feature extraction by analysis of the whole pattern, e.g. using frequency domain transformations or autocorrelation

Abstract

A method for matching grayvalued first elements of a first data set with grayvalued second elements of a second data set so that a first distribution of the first elements optimally matches a second distribution of the second elements, said method being characterized by the following steps: mapping said first elements on said second elements and evaluating a local grayvalue distribution difference between any mapped first element and its associated second element; from said local grayvalue distribution difference deriving for each said first element a force vector of a force field, said force vector indicating a preferred motion size and direction; combining said separate force vectors into a single force and a single torque value acting on said first elements collectively, for iteratively moving said first elements collectively to an amended mapping that improves a match between said first and second distributions.

Claims

1. A method for matching grayvalued first elements of a first data set with grayvalued second elements of a second data set so that a first distribution of the first elements optimally matches a second distribution of the second elements,

said method comprising the steps of:

mapping said first elements on said second elements and evaluating a local grayvalue distribution difference between any mapped first element and its associated second element;

from said local grayvalue distribution difference deriving for each said first element a force vector of a force field, said force vector indicating a preferred motion size and direction; and

combining said separate force vectors into a single force and a single torque value acting on said first elements collectively, for iteratively moving said first elements collectively to an amended mapping that improves a match between said first and second distributions.

2. A method as claimed in claim 1, whilst executing said iteratively moving until a sufficient match is attained.

3. A method as claimed in claim 1, wherein for each said deriving the number of calculations is substantially linear in the number of said first elements.

4. A method as claimed in claim 1, wherein said first and second elements form respective subsets of respective supersets of elements.

5. A method as claimed in claim 4, wherein said subsets are selected on the basis of representing characteristic features of said supersets.

6. A method as claimed in claim 4, wherein said subsets are selected through down-sampling.

7. A method as claimed in claim 1, wherein said combining combines all said vectors into a single force and into a single torque value by preventing said first elements to move with respect to each other.

8. A method as claimed in claim 1, whilst allowing a predetermined amount of motion between the elements of the first distribution.

9. A method as claimed in claim 8, wherein said allowing subjects to an affine transform or a higher order deformation.

10. A method as claimed in claim 1, for medical imaging landmark matching.

11. A method as claimed in claim 1, and applied for one of satellite images, astronomy images, temporal processing of video frames, identification of human or artifact images, and pattern recognition for security, surveillance or reconnaissance.

12. A method as claimed in claim 1, wherein said motion is subjected to a damping restraint.

13. A system being arranged for matching grayvalued first elements of a first data set with grayvalued second elements of a second data set so that a first distribution of the first elements optimally matches a second distribution of the second elements, said system comprising:

a reception facility for receiving said first and second data sets;

a mapping facility fed by said reception facility for mapping said first elements on said second elements and evaluating a local grayvalue distribution difference between any mapped first element and its associated second element;

a force deriving facility fed by said mapping facility for said local grayvalue distribution difference deriving for each said first element a force vector of a force field, said force vector indicating a preferred motion size and direction;

a combining facility fed by said force deriving facility for combining said separate force vectors into a single force and a single torque value acting on said first elements collectively, for iteratively moving said first elements collectively to an amended mapping that improves a match between said first and second distributions, and

a loop facility for retrocoupling said amended mapping to said mapping facility and/or to said force deriving facility.

14. A computer readable medium including code for matching grayvalued first elements of a first data set with grayvalued second elements of a second data set so that a first distribution of the first elements optimally matches a second distribution of the second elements, said medium comprising:

code for mapping said first elements on said second elements and evaluating a local grayvalue distribution difference between any mapped first element and its associated second element;

code for deriving, from said local grayvalue distribution difference, each said first element a force vector of a force field, said force vector indicating a preferred motion size and direction;

code for combining said separate force vectors into a single force and a single torque value acting on said first elements collectively, for iteratively moving said first elements collectively to an amended mapping that improves a match between said first and second distributions.