Segmentation of document images

In a recent paper by Chen et al., the authors present a clever means of decomposing the Laplacian-of-Gaussian (LOG) kernel into the product of a Gaussian and a (smaller) LOG mask. They then proceed to develop a fast algorithm for convolution which exploits thespatial frequency properties of these operators to allow the image tobe decimated (subsampled). Although this approach is both novel andinteresting, the exposition suffers from some inconsistencies and minor errors. We take this opportunity to clarify matters for those who, likeus, wish to implement this technique. Zndex Terms-Edge detection, fast convolution, image processing, Laplacian-of-Gaussian filters.