how to compare the two image objects with different size?

Hi all,

I want to compare two image objects... they look very similar to human 
visual system... but I want to find their similarities by metrics...

The two image objects are embedded in two different large images... I mean, 
they are surrounded by dark or near-dark background in two larger images...

And these two larger images are of different sizes and different sampling 
rate... And the two image objects aren't the same relative locations within 
the larger images...

So how do I dig them out from their background and how do I compensate for 
different sampling rate in comparison?

Thanksa lot 

In article <cq9uqc$2kr$1@news.Stanford.EDU>,
 "lucy" <losemind@yahoo.com> wrote:

> Hi all,
> 
> I want to compare two image objects... they look very similar to human 
> visual system... but I want to find their similarities by metrics...
> 
> The two image objects are embedded in two different large images... I mean, 
> they are surrounded by dark or near-dark background in two larger images...
> 
> And these two larger images are of different sizes and different sampling 
> rate... And the two image objects aren't the same relative locations within 
> the larger images...
> 
> So how do I dig them out from their background and how do I compensate for 
> different sampling rate in comparison?
> 
> Thanksa lot 

google: image warping

google: pattern recognition

-- 
Remove _me_ for e-mail address

Use the brightness feature, as you mentioned, to separate the object 
from the background.  Then, scale teh object to some normlized shape and 
then compare.

Also, this may be of use.. I have found it helpful.

http://www.ece.utexas.edu/~bevans/courses/ee381k/projects/fall00/rajagopal/litSurveyReport.pdf

Isaac


lucy wrote:
> Hi all,
> 
> I want to compare two image objects... they look very similar to human 
> visual system... but I want to find their similarities by metrics...
> 
> The two image objects are embedded in two different large images... I mean, 
> they are surrounded by dark or near-dark background in two larger images...
> 
> And these two larger images are of different sizes and different sampling 
> rate... And the two image objects aren't the same relative locations within 
> the larger images...
> 
> So how do I dig them out from their background and how do I compensate for 
> different sampling rate in comparison?
> 
> Thanksa lot 
> 
>