Bradley, D., Roth, G., June 2007 We present a technique for real-time adaptive thresholding using the integral image of the input. Our technique is an extension of a previous method. However, our solution is more robust to illumination changes

The implemented Sauvola method uses integral images for fast computation of the threshold function. The Sauvola method is described in: J. Sauvola and M. Pietikainen, Adaptive document image binarization, Pattern Recognition 33, 2000. - ht