[Insight-developers] texture features question

[Nicholas Tustison]

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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