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

[dni at cse.cuhk.edu.hk]

Dear Vik,

Maybe intensity remapping before registration,ex. histogram equalization, is
useful since the intensity of your image is within a very limited scope.

Image quality is most important for most of the image processing algorithms.
Good luck.

Quoting 
> 
> Message: 1
> Date: Mon, 21 Jul 2008 22:07:59 -0500
> From: Vikren Sarkar <vikmonster at hotmail.com>
> Subject: [Insight-users] Intensity-based registration with low
> 	contrast	images.
> To: <insight-users at itk.org>
> Message-ID: <BAY124-W25E2EEA074FC46139A4AF4C7850 at phx.gbl>
> Content-Type: text/plain; charset="iso-8859-1"
> 
> 
> 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
>  
> _________________________________________________________________
> Stay in touch when you're away with Windows Live Messenger.
> http://www.windowslive.com/messenger/overview.html?ocid=TXT_TAGLM_WL_messenge
> r2_072008
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL:
> <http://www.itk.org/pipermail/insight-users/attachments/20080721/f273bdeb/att
> achment-0001.htm>