In order to search for image entries at multiple scale, the SIFT detector construct a scale space, defined as follows. Consider the Gaussian kernel. Thus in practice the Frew space is computed by..
In the above code, I have just created an object of Button class you can use any class for this and got the information name in this example from it. The GetProperties actually take either the object or Typeof object to list all the Properties it has in a form of PropertyDescriptorCollection. Similarly, GetEvents will list all the events in the form of EventDescriptor. The code provided in this module can be used in different ccasual.
Alternatively, you can use one pw the low level functions to run only a part of the SIFT algorithm for instance, to compute the SIFT descriptors of custom keypoints.