[Insight-developers] texture features question

[Williams, Norman K]

Which might have something to do with the work I had to do to keep it from
throwing overflow numeric exceptions...


On 5/16/11 8:56 PM, "Luis Ibanez" <luis.ibanez at kitware.com> 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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>>
>>
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