How do you measure the displacement between two images?

[Martin Allen]

Dear All,
I have two 8-bit greyscale images of the same scene,  that are displaced by a small amount. I am looking for a method to measure what this displacement is. I am looking for a simple measure in terms of x, y translation and / or rotation about a point. I am aware of some of the various image registration plugins, and while they can register the images perfectly, they do not give me a measure of the displacement. Any suggestions?
Thanks,
Martin.

[_-3]

Hi Martin,
you can try to use the Block Matching algorithm to detect the
translation of a defined area.
Then you can extend this method with rotation.
This way has some  disadvantages (speed, accuracy depending on the using
area .. ) but will work.

Greetings


Martin Allen schrieb:

> Dear All,
> I have two 8-bit greyscale images of the same scene,  that are displaced by
> a small amount. I am looking for a method to measure what this displacement
> is. I am looking for a simple measure in terms of x, y translation and / or
> rotation about a point. I am aware of some of the various image registration
> plugins, and while they can register the images perfectly, they do not give
> me a measure of the displacement. Any suggestions?
> Thanks,
> Martin.
>
>  

[Joachim Wesner]

Hi,

I think the question was not to find a (new) algorithm to solve the problem
( if it was not for rotation, I also could propose Fourier based fast
correlation....)
but how to TWEAK an existing plugin that already the SOLVES the basic
problem at hand to output the correction vectors it uses!

Martin,

it seems that TurboReg when called from a Macro already has some limited
"Report capabilities" that give image coords before and after the
tranformation
 and it should be pretty easy for the makers of the plugin to output all
transformation parameters used.

I actually am pretty surprised that these plugins usually DO NOT have that
option....!?


Sincerely


Joachim



                                                                           
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Hi Martin,
you can try to use the Block Matching algorithm to detect the
translation of a defined area.
Then you can extend this method with rotation.
This way has some  disadvantages (speed, accuracy depending on the using
area .. ) but will work.

Greetings


Martin Allen schrieb:
> Dear All,
> I have two 8-bit greyscale images of the same scene,  that are displaced
by
> a small amount. I am looking for a method to measure what this
displacement
> is. I am looking for a simple measure in terms of x, y translation and /
or
> rotation about a point. I am aware of some of the various image
registration
> plugins, and while they can register the images perfectly, they do not
give
> me a measure of the displacement. Any suggestions?
> Thanks,
> Martin.
>
>



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