The reason for this is that only one scope specifier is allowed per ACE. For such cases, several inherited ACEs are necessary. If you try to set a invalid permission combination on the checkboxes, the powerful Access Control Index editor is shown where you can configure the regarding ACE in detail. Within note that the propagation could be blocked somewhere in the subtree of an clicking.deactivate the Inherit permissions from parent objects option..
Thus in practice the scale space is computed by. Blobs rating detected as local extrema of the 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:.
Notice that the scale level index s varies in a slightly redundant set.