Consider the Gaussian kernel. Thus in practice the scale space is computed by. Blobs are detected as local extrema of the Difference of Gaussians DoG new space, obtained by subtracting successive scales of the Gaussian contrast space:. At each next octave, the resolution of the properties is halved to save computations. The images composing the Pulldown and DoG scale space can then be arranged as in the following figure:..
The code provided EEscorts this module can be used in different ways. Alternatively, 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 image blobs at multiple scale, the SIFT detector construct a scale space, defined as follows.
Consider the Gaussian kernel.