 |
 |
Hi, Sorry for the delay in responding - I just got back from holiday. The searchrz option specifies the initial range for the primary search phase of the registration but it does not restrict the final transformation. In fact there is no option in FLIRT to impose a hard constraint on the transformation. If it finds that there is a local minima nearby then it will keep going until it finds it, regardless of how far "away" that is. What the real problem seems to be is that things fail for you. It is probably important, based on our experience with spinal cord imaging, to use a cost function weighting image that just covers the cord area and ignores large areas outside of this. Also, the resolution will be important - how many voxels inside the cord do you have? And do you have large fluctuations in the intensity of the CSF surrounding the cord? All of these are probably crucial issues. I hope this helps. All the best, Mark Bennett Landman wrote: > > Good morning, > > I need to perform a constrained 2D (x,y-translation + z-rotation) > registration for spinal cord studies. If I use the FLIRT sch2D_3dof > file, about 10-20 percent of the time, the registration wildly fails > with a large rotation. The option –searchrz seems to have no effect. > How can I limit the rotation search to +-5 degrees? > > I am using flirt 5.4.2. > > Thanks! > > Bennett > > ------------------------------------------- > > Bennett Landman, [log in to unmask] <mailto:[log in to unmask]> > > Ph.D. Candidate, Biomedical Engineering > > Johns Hopkins University School of Medicine >