chirp
Projective Chirp
- (a) In image processing, direct periodicity seldom occurs, but, rather, periodicity-in-perspective is encountered.
- (b) Repeating structures like the alternating dark space inside the windows, and light space of the white concrete, “chirp” (increase in frequency) towards the right.
- (c) Thus the best fit chirp for image processing is often a projective chirp.
Full Article: http://en.wikipedia.org/wiki/Chirp