Re: Changing amount of sharpen and smooth

Posted by Gabriel Landini on Apr 11, 2010; 2:40pm
URL: http://imagej.273.s1.nabble.com/Changing-amount-of-sharpen-and-smooth-tp3688605p3688608.html

On Sunday 11 April 2010, you wrote:
> On larger image i can't use 3x3 kernel, it isn't same sharpen. I should use
> (275/3)/(1600/3) = 5 * 3 = 15, so convolve15x15 i guess :)
> So is there any option in my case?

I agree with Michael,  you can't do *strictly* what you want because the two
images have different data. Just scaling the kernel will not give you exactly
the same result as a smaller kernel on the smaller image unless you take into
relation how the small image was subsampled when reduced and so on.

The option in this case is to take a subimage of the original (no smaller,
just a subpart of it) and test the filters in that.
This way you have exactly the same filtering as you saw in the small image.

G.