[Insight-users] Registration - Mutual Information Metric - Sampling from Moving Image

[Sharath Venkatesha]

Hi,

I am working with images where the Fixed image is 2000*2000 pixels and the moving image is 640*480 (sub region of the fixed image). In all the Mutual Information metrics, the sampling is done on the Fixed image, and the transformed points are mapped on the moving image. 

I figured out that it is incorrect to sample the points randomly in the full fixed image ( as in my case, the moving image is a sub-part of the fixed image, and only 30-40% points were mapped), I used an approximate region of the fixed image from which sampling should be done. This has not improved the performance/accuracy of registration. 

I am thinking of sampling pixels from the moving image, and do a backward mapping to pixels in the fixed image. In this case, I think that almost all the points will be mapped, and hence the metric will be better. 

Do I need to change the functions in the respective files, or is there a simpler way to do this, or is already implemented?

Thanks,

Sharath Venkatesha