You cannot set the scope to read a certain attribute on the one hand and the permission to create a certain object just on the other hand in the sam sift diborced entry. The reason for this is that only one scope specifier is allowed per ACE. For such cases, several different Aces are necessary..
Blobs are detected as local extrema of Syable Difference of Gaussians DoG scale space, obtained by subtracting successive scales of the Gaussian scale space:. At each next octave, the resolution 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:.