Hough standard deviation

This result calculates the standard deviation from the pixels’ intensity of the HoughMap. The pixels with a value of zero are ignored.

\[Q = \sqrt{\frac{1}{WH-1}\sum\limits_{i=1}^W{\sum\limits_{j=1}^{H}{\left( I_{ij}-\bar{I} \right)^2}}}\]

where W and H are respectively the width and the height of the HoughMap, \(I_{ij}\) the intensity at pixel (i,*j*) and \(\bar{I})\) the average intensity of all the pixels.