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Re: Histogram modification before auto thresholding

Posted by michael shaffer on Apr 24, 2006; 10:47am
URL: http://imagej.273.s1.nabble.com/Histogram-modification-before-auto-thresholding-tp3703002p3703006.html

 
Gabriel writes ...

> 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.

  I believe you are correct, however, the mystery remains.  Why are there 2
methods?

Genuinely, Michael Shaffer  :o)

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> > 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.
>
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