[Insight-developers] texture features question

[Nicholas Tustison]

Thanks.  I'll submit a patch.


On May 16, 2011, at 9:56 PM, Luis Ibanez wrote:

> Yeap, it looks like a bug.
> 
> The implementation of Histogram will misuse the value
> of max()+1:
> 
> 
> itkHistogram.txx : lines 237-249:
> 
> 
> Histogram< TMeasurement, TFrequencyContainer >
> ::Initialize(const SizeType & size, MeasurementVectorType & lowerBound,
>             MeasurementVectorType & upperBound)
> {
>  this->Initialize(size);
> 
>  float interval;
>  for ( unsigned int i = 0; i < this->GetMeasurementVectorSize(); i++ )
>    {
>    if ( size[i] > 0 )
>      {
>      interval = static_cast<float>( upperBound[i] - lowerBound[i] )
>        / static_cast< MeasurementType >( size[i] );
> 
> ---
> 
> 
>     Luis
> 
> ----------------------------
> On Mon, May 16, 2011 at 9:50 PM, Nicholas Tustison <ntustison at gmail.com> 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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>> 
>>