[Insight-developers] texture features question

[Bradley Lowekamp]

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
>>> 
>>> 
>>> 
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> _______________________________________________
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> 
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