Feature detection as in 1999: SIFT explained with Python implementation

SIFT (Scale Invariant Feature Transform) is a feature detection algorithm in computer vision to detect and describe local features in images. It was created by David Lowe from the University British Columbia in 1999. David Lowe presents the SIFT algorithm in his original paper titled Distinctive Image Features from Scale-Invariant Keypoints.

This is a companion discussion topic for the original entry at http://iq.opengenus.org/scale-invariant-feature-transform/