Re: Histogram modification before auto thresholding

Posted by Gabriel Landini on Apr 24, 2006; 9:13am
URL: http://imagej.273.s1.nabble.com/Histogram-modification-before-auto-thresholding-tp3703002p3703005.html

On Monday 24 April 2006 03:56, Cheok Yan Cheng wrote:
> Recently, when I try out the auto-threshold function
> in ImageJ, I found that two following two methods
> produce completely different result:
>
> (A) Process->Binary->Threshold
> (B) Image->Adjust->Threshold…

They are 2 different things.

> It seems that if the largest histogram is much greater
> (2x) than the 2nd largest histogram, the largest
> histogram will be reduced to 1.5x of the 2nd largest
> histogram.
>
> May I know what is the reasons behind for doing so? Is
> there any more information on this?

I believe that this is for display purposes (so one does not get a very large
peak in the image histogram).

> P/s For my case, my image get much better result
> through (B)

I don't think so. Method A is to *adjust* the threshold value. Method B
converts the image into a binary image according to the *current* value set
(either manually or automatically using method A).

I hope it helps.
G.