Re: Leveling Image

Posted by Gabriel Landini on Aug 23, 2011; 10:29am
URL: http://imagej.273.s1.nabble.com/Leveling-Image-tp3683357p3683367.html

On Tuesday 23 Aug 2011, Ahsan wrote:
> I have already removed the non uniform background from the original image
> by fitting a plane on it and subtracting from the original image.

Why you to fit a plane and subtract it before correcting the image bands?
Doesn't that change the topography of the image? and doesn't this also change
the offset that needs to be corrected so now it is not a constant offset along
the line anymore?

> subtracting the median from each line individually but i couldn't find
> much reading material about it that could explain why will it not remove
> the actual data and only the artifacts.

If you offset according to the median of  all the data in the line (as opposed
to a known reference that should be originally constant across lines, such as
a portion of background) this offset is not guaranteed to be the right one
unless the image is quite homogeneous.

If the data indeed goes up, the median (and hence the offset) will  probably
go up too, but the line perhaps does not need to be made darker than it is
just because the median is large.

Sorry I do not have any further suggestions other than improving the scanning
quality. Maybe there is a standard method used in AFM, but I am not familiar
with this.

Cheers

Gabriel