Research Image Registration Algorithm Based On Mutual Information

Image registration is the basis of image processing technology, it is an importantprerequisite for image mosaic, image fusion, target tracking. Because of the image scale isincreasing now, the image information is more complex, automatic registration became theprimary method of registration and an important research direction.The registration algorithmthat based on image gray registration mutual information does not need to do image extractingfeatures pretreatment operation, less intervention, higher degree of automation, theregistration precision is higher than other based on image segmentation methods, and thismethod can apply to multiple modal image, good robustness. Therefore, this paper researchesthe registration method based on the mutual information of images. The main tasks are:(1) A detailed study of the basic theory of mutual information and basic principles ofmutual information registration method, and have two images registration simulation inmatlab, analyze the performance of this algorithm from the result.(2) For the questions that nearest neighbor interpolation inefficient, linear interpolationtake in the gray will impact the calculation of joint histogram, this paper researches the PVinterpolation techniques. This interpolation technique is more efficient, does not take in newgray, and effectively inhibit the substantial transformation of the mutual information, it isgood for the registration parameters optimization.(3) For the question that basic Powell optimization algorithm can not guarantee that thesearch direction linearly independent and this will lead to be not good for objective functionsearching the extreme points, researching the modified Powell algorithm to ensure that whenreplace the search direction is linearly independent.(4) For the question that mutual information registration method is inefficient, andregistration precision low, research one image registration method that based on wavelettransform and mutual information. To decompose images with wavelet transform, and tofinish tiered registration.The results show that registration method based on wavelet transform and mutualinformation not only saves time, but also improve the registration accuracy. And be comparedwith the mutual information registration method, which is higher efficiency and betterstability, to achieve the purpose of improvement of the mutual information algorithm.