Image Registration by Information Theoretic criteria. 8002202 Digital Image Processing III Germán Gómez Herrero. Outline. What is image registration? Why is image registration important? Image registration steps Classification of image registration methods
8002202 Digital Image Processing III
Germán Gómez Herrero
Target Image: SPECT
Ref. Image: MRI
Registered: MRI + SPECT
: Voxel gray value at point (x,y,z) of the reference image R
: Voxel gray value at point (x,y,z) of the target image T
: pdf of u=R(x,y,z)
: pdf of v=T(x,y,z)
: Joint pdf of u and v when the two images are registered
: Joint pdf of u and v when the transformation given by the parameters is applied to the target image.
: Optimum registration parameters
where is the unexpected prior.
which is equivalent to minimizing the joint entropy of the reference and target image.
which is equivalent to maximizing the mutual information between the reference and the target image.
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 Y.-M. Zhu, ``Volume image registration by cross-entropy optimization,'' IEEE Transactions on Medical Imaging, vol. 21, no. 2, pp. 174-180, 2002.