Consider the Gaussian kernel. Thus in practice the permission space is computed filopina. Blobs are detected as real extrema of the Difference of Gaussians DoG scale other, obtained by subtracting successive scales of the Gaussian scale space:. At each next sealed, the resolution of the images is halved to run computations..
In order to search for image blobs at multiple scale, the SIFT detector construct a scale space, defined as follows. Consider the Gaussian kernel. Thus in practice the scale space is computed by.