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Thread Subject:
Image processing and alignment

Subject: Image processing and alignment

From: Deepak Sankar

Date: 13 Jul, 2010 16:43:05

Message: 1 of 4

Hey all,,

I have a question with image alignment. I have two sets of height data of a surface at different temperatures from an experiment. The data set has both translation and rotation. The data is saved as matrix format. Now i need to align those data sets.. What I have done is, I converted the matrix to gray format using mat2gray and found the edges of feature on the surface using canny filter. I found the angle by selecting a set of points in edge plot (logical data set) and fitted a line to it and then found the angle for that line. I have removed the rotation from both the data set using imrotate. Now the angle is removed I need to correct for translation in x and y.
   Since I am doing the experiement at different temperatures some noise factor add in to the data set. I know I can use cpselect for manually selecting the contol points and then find the translation. Wondering if there is any automatic way of doing it?

Thanks
Deepak

Subject: Image processing and alignment

From: Deepak Sankar

Date: 13 Jul, 2010 16:53:04

Message: 2 of 4

Forgot to add in this... Normalized Cross-Correlation isn't working well because of noise factor...

Subject: Image processing and alignment

From: Sean

Date: 13 Jul, 2010 18:05:08

Message: 3 of 4

"Deepak Sankar" <deepaksankar@yahoo.com> wrote in message <i1i5lg$1a2$1@fred.mathworks.com>...
> Forgot to add in this... Normalized Cross-Correlation isn't working well because of noise factor...

Do a search on here for "phase correlation." It can handle both rotations and translations as well as scaling. Also it's fairly resilient to noise and intensity differences.

Subject: Image processing and alignment

From: Sean

Date: 13 Jul, 2010 18:06:10

Message: 4 of 4

"Deepak Sankar" <deepaksankar@yahoo.com> wrote in message <i1i5lg$1a2$1@fred.mathworks.com>...
> Forgot to add in this... Normalized Cross-Correlation isn't working well because of noise factor...

Also, see this submission:
http://www.mathworks.com/matlabcentral/fileexchange/18401-efficient-subpixel-image-registration-by-cross-correlation

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