Prev: Help with graphing please
Next: Loading into GUI
From: Deepak Sankar on 16 Jun 2010 14:12
Hey all, I have a question about aligning data. I am measuring height of surface at two different temperature using optical profilling system. The data is stored in a matrix format. Since I do measurements at different temperatures the alignement of the test sample changes. I need to know the height difference at different temperature difference along a particular section. For this, the data has to be aligned. Wondering how to go about it, since i dont know the angle of rotation.

Thanks
Deepak
From: ImageAnalyst on 16 Jun 2010 15:22
You have two different matrices. So how can you know how much of the
difference is caused by lateral alignment differences and how much is
due to height differences? Now if you had the same image and it was
just shifted, you could do something. And if you knew the sample
didn't shift at all, then you could say that the difference was solely
due to height changes as it heated up. But if you have both height
changes and translation/rotation, it's tough or impossible, depending
on the magnitude of those changes. Not to mention boundary effects as
some parts of your sample may be in one of the image but not the
other. There might be some registration methods out there than can
translate/rotate/warp and try their best to also match intensity on
the translated/rotated/warped images. I haven't used any though.

You might try here:
12 Registration, Matching and Recognition Using Points, Lines,
Regions, Areas, Surfaces
http://iris.usc.edu/Vision-Notes/bibliography/contentsmatch-pl.html#Registration,%20Matching%20and%20Recognition%20Using%20Points,%20Lines,%20Regions,%20Areas,%20Surfaces
From: Deepak Sankar on 28 Jun 2010 14:02
Hey,

I have tried few methods. Cross-correlation doesnt seem to work.
So I create a contour plot of the height data and save it as a jpg file and by using bwmorph I clean the image. Then I use cpselect for lower and higher temperature image file to find the angle and scaling factor.

I am not sure if this is the right way of doing it. And I am also stuck on how to transform the matrix of height data knowing the angle and scaling factors. Any idea on how to go about it..

Thanks
Deepak
From: ImageAnalyst on 28 Jun 2010 16:52
Use maketform() and tformfwd().
 | 
Pages: 1
Prev: Help with graphing please
Next: Loading into GUI