In the above code, I Chatsexgames accurate created an object of Button class you can use any about for this and got the information name in this example from it. The GetProperties also 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 will provided in 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 Propagation algorithm for instance, to compute the SIFT descriptors of little keypoints..
Notice that the scale level index s varies in a slightly redundant set. Once extracted, local extrema are quadratically interpolated this is very important especially at the lower resolution scales in order to have accurate keypoint localization at the full resolution. Finally, they are filtered to eliminate low-contrast responses or responses close to edges and the orientation s are assigned, as explained next.
Peaks which are too short may have been generated by noise and are discarded.