Hello All,<br><div class="gmail_quote"><br>I have a problem with the Diffeomorphic Demons registration.<br>Hope anyone can give me some suggestions. <br>Thanks in advance.<br><br>I used the DiffeomorphicDemonsRegistrationWithMaskFilter with two level resolutions, <br>
the main parameters of the filter is below :<br><br>MaximumRMSError = 0.01;<br>MaximalStepLength[ ] = {2, 1};<br>DemonsNumOfIterations[ ] = {6, 10};<br>double DemonsElasticSigma [ ] = {0.8, 0.4} ;<br>double DemonsViscousSigma[ ] = {0.8, 0.4} ;<br>
<br>I set an observer of the filter to print out the RMS change in each iteration.<br>The registration results is quite well if the registration is run sucessfully.<br>However, the result is not stable. In many cases, the observer print out the RMS change is "nan", and no deformation field is generated.<br>
The program can run through in this situation, and there is no exception error caught . <br><br>The normal RMS change of my test images always goes from around 0.3 to 0.1, <br>so I think it is not the reason that the value is nonreprentable, which is the defination of "nan".<br>
The same images with the same parameters in the program can obtain sucessful registration results sometime, and failed with the RMS changes "nan".<br><br>You need to run the program four or five times, and possible the registration will be sucessful once if i am lucky enough.<br>
<br>I don't know what the reason of this unstable problem, and hope someone can figure me out. <br><br>Thanks.<br><br>Kind regards,<br><font color="#888888">Chunfang<br><br>
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