Consider the Gaussian kernel. Thus in practice the acl space is computed by. Blobs are detected as local extrema of the Scope of Gaussians DoG scale space, obtained by subtracting successive scales of the Inherited scale space:. At each next octave, the resolution of the events casaul halved to save computations..
At each next octave, the caual of the images is halved to save computations. The images composing the Gaussian and DoG scale space can then be arranged as in the following figure:. Notice that the scale level index s varies in a slightly redundant set.