[Insight-developers] texture features question

[Nicholas Tustison]

Thanks, Brad, you're certainly right.  It's open-ended on the right, it seems, and it's too late
to think intelligently on the issue.  I'll have to revisit this later.  Thanks again.







On May 16, 2011, at 10:00 PM, Bradley Lowekamp wrote:

> Nick,
> 
> I think that the issue that Luis is talking about is wether the bound is [0,1], [0,1), or (0,1), where [ is for a closed end-point and ( is for an open end point of an interval. Then how this is propagated to the individual bins. I recall that there is an issue with needing padding because of a open end-point in one or two places.
> 
> Hope this helps,
> Brad
> 
> On May 16, 2011, at 9:50 PM, Nicholas Tustison wrote:
> 
>> Thanks Luis.  If you go to lines 168-169, the lower and upper bounds
>> are used to initialize the joint histogram.  
>> 
>> size.Fill(m_NumberOfBinsPerAxis);
>> output->Initialize(size, m_LowerBound, m_UpperBound);
>> 
>> Was that what you were asking about?
>> 
>> The problem is that if everything is the same except the intensity range of one 
>> image is scaled between [0,256] and its counterpart is scaled between [0,1],
>> creating a histogram which spans between [0, 257] on each axis is going to be 
>> quite different from one that spans between [0,2].  
>> 
>> 
>> 
>> 
>> On May 16, 2011, at 9:43 PM, Luis Ibanez wrote:
>> 
>>> Hi Nick,
>>> 
>>> Yeap, that looks like a bug.
>>> 
>>> Although, to make sense of it,
>>> we have to dive into how the
>>> bounds are used in the histogram
>>> computation...
>>> 
>>> 
>>>   Luis
>>> 
>>> 
>>> --------------------------------------------------
>>> On Mon, May 16, 2011 at 9:19 PM, Nicholas Tustison <ntustison at gmail.com> wrote:
>>>> Hi,
>>>> 
>>>> I've been working with the cooccurrence matrix texture features classes and noticed that
>>>> if I simply rescale the values, the texture measures are completely different.  I tracked it
>>>> down to lines 384 and 385 of itkScalarImageToCooccurrenceMatrixFilter.txx which the
>>>> user uses to set the min and max values of the joint histogram:
>>>> 
>>>> m_LowerBound.Fill(min);
>>>> m_UpperBound.Fill(max + 1);
>>>> 
>>>> It would seem that line 385 should, instead, be
>>>> 
>>>> m_UpperBound.Fill(max);
>>>> 
>>>> Does that make sense or am I missing something?
>>>> 
>>>> Thanks,
>>>> Nick
>>>> 
>>>> 
>>>> 
>>>> _______________________________________________
>>>> Powered by www.kitware.com
>>>> 
>>>> Visit other Kitware open-source projects at
>>>> http://www.kitware.com/opensource/opensource.html
>>>> 
>>>> Kitware offers ITK Training Courses, for more information visit:
>>>> http://kitware.com/products/protraining.html
>>>> 
>>>> Please keep messages on-topic and check the ITK FAQ at:
>>>> http://www.itk.org/Wiki/ITK_FAQ
>>>> 
>>>> Follow this link to subscribe/unsubscribe:
>>>> http://www.itk.org/mailman/listinfo/insight-developers
>>>> 
>> 
>> _______________________________________________
>> Powered by www.kitware.com
>> 
>> Visit other Kitware open-source projects at
>> http://www.kitware.com/opensource/opensource.html
>> 
>> Kitware offers ITK Training Courses, for more information visit:
>> http://kitware.com/products/protraining.html
>> 
>> Please keep messages on-topic and check the ITK FAQ at:
>> http://www.itk.org/Wiki/ITK_FAQ
>> 
>> Follow this link to subscribe/unsubscribe:
>> http://www.itk.org/mailman/listinfo/insight-developers
>