In this paper, a technique for registering medical images captured through different modalities with focus on portal image is been discussed. Earlier template matching was used to register satellite images, but it does not serve the purpose as images are from different modalities and same objects are represented with different intensity values. Mutual information based techniques outperform other multimodal techniques for this application because of inherently poor quality acquired image through MV image during patient treatment. This technique will suffer if image is very blurry. The technique is to maximize the mutual information between two images using gradient ascent method.

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Registration Computer Vision Information Theory Optimisation Entropy