Development of a Digital Shearlet Transform Based on Pseudo-Polar FFT

Shearlab is a Matlab toolbox for digital shearlet transformation of two-D (image) data we developed following a rational design process. The Pseudo-Polar FFT fits very naturally with the continuum theory of the Shearlet transform and allows us to translate Shearlet ideas naturally into a digital framework. However, there are still windows and weights which must be chosen. We developed more than a dozen performance measures quantifying precision of the reconstruction, tightness of the frame, directional and spatial localization and other properties. Such quantitative performance metrics allow us to: (a) tune parameters and objectively improve our implementation; and (b) compare different directional transform implementations. We present and interpret the most important performance measures for our current implementation.