Re: Java SIFT plugin for ImageJ : Question on parametage

Posted by Xin ZHOU on Sep 30, 2008; 3:50pm
URL: http://imagej.273.s1.nabble.com/Java-SIFT-plugin-for-ImageJ-Question-on-parametage-tp3694919p3694926.html

Hi, Albert,

What is the exact definition of this "image size"?
I means, for me it is the size of the part that we want to study. Which
is, the study window size.
Because basically the image size depends on image itself, we cannot set
a value for that.
If I'm wrong please tell me.

In this case, I will be confused by "If the image is larger, the window
is looking at comparatively a smaller region"
I'm enlarging the window, isn't it?

"If the image is larger" means somehow we are able to enlarge the
original image.
If this is true, than I just want the size to be the original size of
image, what should I do?

Albert Cardona a écrit :

> Hi Xin,
>> I don't understand why if I enlarger the maximum image size, I'll
>> discard the larger features ....
>> I presume that the larger features are for the larger scale, right?
>> Then larger scale can only be detected in larger window.
> Exactly the opposite. Keep in mind that features are found by moving
> around a fixed size NxN pixel window. If the image is larger, the
> window is looking at comparatively a smaller region of the overall
> image, and thus it's extracting small features.
>
> Hope that helps,
>
> Albert
>