[Insight-users] OtsuThresholdImageFilter

[Radhika Sivaramakrishna]

Hi Luis,
Thanks for your prompt response. Yes, I did have a couple of questions.

1) I checked the documentation for OtsuMultipleThresholds. It is
templated on input histogram. It says you have to specify the target
histogram. What does this mean? Is there a way to just pass the original
image with the number of thresholds you want to identify, and it should
return the thresholds that best separate the multiple classes?

2) Do you have recommendations for other types of filters/methods I can
use to separate an image into essentially three portions, a background
which is darker, a foreground, another region within foreground which in
general is brighter than the rest of the foreground.

Thanks
Radhika


-----Original Message-----
From: Luis Ibanez [mailto:luis.ibanez at kitware.com] 
Sent: Wednesday, October 27, 2004 3:41 PM
To: Radhika Sivaramakrishna
Cc: insight-users at itk.org
Subject: Re: [Insight-users] OtsuThresholdImageFilter


Hi Radhika,


In the Doxygen documentation, there are entries for the three classes

http://www.itk.org/Insight/Doxygen/html/classitk_1_1OtsuThresholdImageFi
lter.html
http://www.itk.org/Insight/Doxygen/html/classitk_1_1OtsuMultipleThreshol
dsCalculator.html
http://www.itk.org/Insight/Doxygen/html/classitk_1_1OtsuThresholdImageCa
lculator.html


The classes

        OtsuMultipleThresholdsCalculator
        OtsuThresholdImageFilter

are relatively new,


the first one dates from March, (contributed by Luca Antiga)
the second dates from July



OtsuMultipleThresholds allows you to compute thresholds from
gray scale statistical distributlis that are multimodal, while
the original OtsuThreshold calculator was intended for Bimodal
distributions.


The OtsuThresholdImageFilter it a thresholding filter that
internally computes the threshold for you image by using
an OtsuThresholdCalculator.



   Please let us know if you have further questions,


     Thanks


       Luis



------------------------------
Radhika Sivaramakrishna wrote:

> Hi all,
> 
> In the documentation only the OtsuThresholdImageCalculator is written.

> However, in the Insight library, we also have 
> OtsuMultipleThresholdsCalculator and OtsuThresholdImageFilter.
> 
> Does anyone know how to use these, and why are they not available in
the 
> documentation?
> 
> Thanks
> 
> Radhika
> 
>  
> 
> 
>
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