Editing Edge detection (section)

=== Phase Stretch Transform (PST) ===
[[File:PST edge detector saint Paul.tif|thumb|500px| Feature enhancement in an image ([[St Paul's Cathedral]], London) using Phase Stretch Transform (PST). Left panel shows the original image and the right panel shows the detected features using PST.]]

The [[phase stretch transform]] or PST is a physics-inspired computational approach to signal and image processing. One of its utilities is for feature detection and classification.<ref name="original">M. H. Asghari, and B. Jalali, [https://downloads.hindawi.com/journals/ijbi/2015/687819.pdf "Edge detection in digital images using dispersive phase stretch,"] International Journal of Biomedical Imaging, Vol. 2015, Article ID 687819, pp. 1–6 (2015).</ref><ref>M. H. Asghari, and B. Jalali, "[https://ieeexplore.ieee.org/abstract/document/7032125/ Physics-inspired image edge detection]," IEEE Global Signal and Information Processing Symposium (GlobalSIP 2014), paper: WdBD-L.1, Atlanta, December 2014.</ref> PST is a spin-off from research on the [[time stretch dispersive Fourier transform]]. PST transforms the image by emulating propagation through a diffractive medium with engineered 3D dispersive property (refractive index). The operation relies on symmetry of the dispersion profile and can be understood in terms of dispersive eigenfunctions or stretch modes.<ref>B. Jalali and A. Mahjoubfar, "[https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=7118650 Tailoring Wideband Signals With a Photonic Hardware Accelerator]," Proceedings of the IEEE, Vol. 103, No. 7, pp. 1071–1086 (2015).
</ref> PST performs similar functionality as phase contrast microscopy but on digital images. PST is also applicable to digital images as well as temporal, time series, data.