[Insight-users] Histogram-Size for Histogram-Metric

[Raghavendra Chandrashekara]

Hi Michael,

The choice of histogram size will depend on the distribution of 
intensities in the images that you are using. I have found that for 
cardiac  TrueFISP MR images a resonable choice is 64 x 64.

Raghavendra

Michael wrote:

> Hi,
>
> when using one of the metric classes derived from 
> HistogramImageToImageMetric, what is a reasonable size for the 
> histogram? I've noticed that the default size is set to 256x256. If an 
> image pixel is represented by an 8-bit value, this would mean we have 
> a histogram bin for every intensity value pair that can occur. Is this 
> reasonable in any case? I mean, if a pixel is coded using, say, 16 
> bits, should the histogram size be 2^16*2^16? This would obviously 
> increase the computational complexity, since instead of iterateing 
> through (2^8)^2 = 2^16 bins we now have to iterate through more that 
> (2^16)^2 = 2^32 > 4*10^9 bins in the EvaluateMeasure method.
>
> Are there any hints that help to estimate a reasonable histogram size?
>
> Thanks,
>
> Michael
>
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