1. Department of Informatics, Aristotle University of Thessaloniki, May 4, 2001 ARISTOTLE UNIVERSITY OF THESSALONIKI. DEPARTMENT OF INFORMATICS Stelios Krinidis 2D/3D Image Registration and Alignment: A Review

2. Department of Informatics, Aristotle University of Thessaloniki, May 4, 2001 Presentation outline Definitions General aspects ICP algorithm Shape-based algorithm References

3. Department of Informatics, Aristotle University of Thessaloniki, May 4, 2001 Definitions Registration: a fundamental task in image processing used to match two or more pictures taken, for example, at different times, from different sensors, or from different viewpoints. Alignment: a fundamental task in image processing used to match two or more pictures that are similar but not alike, for example different sections from a 3D object.

4. Department of Informatics, Aristotle University of Thessaloniki, May 4, 2001 General aspects (1) Registration/Alignment can be used to: 3D object reconstruction from its 2D sections. 3D object visualization and morphological analysis. Compare medical tissues (taken at different times) showing tumor growth, internal abnormalities, etc. Medical and surgical analysis, tests and simulations.

5. Department of Informatics, Aristotle University of Thessaloniki, May 4, 2001 General aspects (2) Registration/Alignment (2D and 3D) compensation: rotation and translation (MRI, CT, etc) non-rigid transforms (physical sectioning of biological tissues, anatomical atlases, etc)

6. Department of Informatics, Aristotle University of Thessaloniki, May 4, 2001 General aspects (3) Proposed Registration/Alignment methods: fiducial marker-based feature-based using contours crest lines or characteristics points gray level-based

7. Department of Informatics, Aristotle University of Thessaloniki, May 4, 2001 Iterative Closest Point (ICP) It can be used with the following representations of geometrical data:  points sets  line segments (polylines)  implicit curves: g (x,y,z) = 0  parametric curves: (x(u),y(u),z(u))  triangle sets (faceted surfaces)  implicit surfaces: g(x,y,z) = 0  parametric surfaces: (x(u,υ),y(u,υ),z(u,υ))

8. Department of Informatics, Aristotle University of Thessaloniki, May 4, 2001 Iterative Closest Point (ICP) Characteristics: monotonic convergence to the nearest local minimum rapid convergence during the first few iterations global convergence depends on the initial parameters

9. Department of Informatics, Aristotle University of Thessaloniki, May 4, 2001 Iterative Closest Point (ICP) Model point set: Data point set: Closest point set: Distance metric:

10. Department of Informatics, Aristotle University of Thessaloniki, May 4, 2001 Iterative Closest Point (ICP)

11. Department of Informatics, Aristotle University of Thessaloniki, May 4, 2001 Iterative Closest Point (ICP) Quaternion is the eigenvector related to the largest eigenvalue:

12. Department of Informatics, Aristotle University of Thessaloniki, May 4, 2001 Iterative Closest Point (ICP)

13. Department of Informatics, Aristotle University of Thessaloniki, May 4, 2001 Iterative Closest Point (ICP) Point Set Matching

14. Department of Informatics, Aristotle University of Thessaloniki, May 4, 2001 Iterative Closest Point (ICP) Curve Set Matching

15. Department of Informatics, Aristotle University of Thessaloniki, May 4, 2001 Iterative Closest Point (ICP) Surface Set Matching

16. Department of Informatics, Aristotle University of Thessaloniki, May 4, 2001 Shape-Based Alignment Alignment of 2D serially acquired sections forming a 3D object Characteristics: shape-based algorithm (contours) global energy function (expressing similarity between neighboring slices). no direction is privileged no global offset no error propagation

17. Department of Informatics, Aristotle University of Thessaloniki, May 4, 2001 Shape-Based Alignment N :frame number N x :horizontal image dimension N y :vertical image dimension R :neighborhood’s length f :pixel similarity metric

18. Department of Informatics, Aristotle University of Thessaloniki, May 4, 2001 Shape-Based Alignment D i :Distance Transform of image i

19. Department of Informatics, Aristotle University of Thessaloniki, May 4, 2001 Shape-Based Alignment Distance Transform: each pixel has value equal to the pixel’s distance from the nearest non-zero pixel.

20. Department of Informatics, Aristotle University of Thessaloniki, May 4, 2001 Shape-Based Alignment Alignment Errors Statistics

21. Department of Informatics, Aristotle University of Thessaloniki, May 4, 2001 Shape-Based Alignment Alignment Errors Statistics

22. Department of Informatics, Aristotle University of Thessaloniki, May 4, 2001 Shape-Based Alignment

23. Department of Informatics, Aristotle University of Thessaloniki, May 4, 2001 Shape-Based Alignment

24. Department of Informatics, Aristotle University of Thessaloniki, May 4, 2001 Shape-Based Alignment

25. Department of Informatics, Aristotle University of Thessaloniki, May 4, 2001 References 1)P. Van den Elsen, E.J.D. Paul, and M.A.Viergever. Medical Image Matching – A review with classification. IEEE engineering in Medicine and Biology, 12(1):26-39, 1993. 2)M.J.Besl and N.McKay. A Method for the Registration of 3D Shapes. IEEE transactions of Pattern Analysis and Machine Intelligence(PAMI), 14(2):239-256, 1992 3)G.Borgefors. Hierarchical Chamfer Matching: A parametric edge matching algorithm. IEEE transactions of Pattern Analysis and Machine Intelligence(PAMI), 679-698, 1986. 4)W.Wells III, P.Viola, H.Atsumi, S.Nakajima, and R.Kikinis. Multimodal volume registration by maximization of mutual information. Medical Image Analysis, 1(1):33-51, 1996.

26. Department of Informatics, Aristotle University of Thessaloniki, May 4, 2001 References 5)C.Nikou, J.P.Armspach, F.Heitz, I.J.Namer, and D.Grucker. MR/MR and MR/SPECT registration of brain by fast stochastic optimization of robust voxel similarity measures NeuroImage, 8(1):30-43, 1998. 6)S.Krinidis, N.Nikolaidis, I.Pitas. Shape Based Alignment of 3-D Volume Slices. I nternational Conference on Electronics, Circuits and Systems (ICECS'00) Kaslik, Lebanon, 17-20 September 2000.