[Insight-users] Intensity-based registration with low contrast images.

[Vikren Sarkar]

Greetings, 
 
I am trying to see if it is possible to perform intensity-based registration on some very low contrast images that I have. I tried posting this question a few days ago but realize there were some problems with the website I was using. Hopefully photobucket will be better. The following two images were acquired using an electronic portal imaging device. The only difference is that one image is translated compared to the other. 
 
File 1 : http://i336.photobucket.com/albums/n333/poohvee/fixed.jpg
 
File 2 : http://i336.photobucket.com/albums/n333/poohvee/moving.jpg
 
Being new to ITK, I first started with several of the example registration codes but none seem to work with the low contrast level. Luis also suggested I try to run the images through edge detection. I tried that approach as well as thresholding before registering but could not get any results with any of the example registration codes. Finally, I did try the example code using mutual information (example 2 in image registration) and it did not work either. 
 
Does anyone have any other suggestion I can use to artificially increase the contrast before registering or can someone suggest a metric that would be better suited for the task? The final aim would be to try to use this with 3D datasets but I would like to start with 2D. Thank you. 
Vik
 
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