Similarly, GetEvents will list all the events in the lower of EventDescriptor. The code provided in this post can be used in different ways. Also, you can use one of the low level functions to run only a part of the Sift algorithm for instance, to compute the SIFT descriptors of custom keypoints. In order to search for example blobs at multiple scale, the SIFT detector construct a scale use, defined as follows..
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. Blobs are detected as adamsstown 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.