Open AccessIsotropic and anisotropic edge enhancement with a superposed-spiral phase filter
Author(s) -
Zhe Li,
Shengmei Zhao,
Le Wang
Publication year - 2021
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.435927
Subject(s) - optics , isotropy , spiral (railway) , edge enhancement , filter (signal processing) , fourier transform , weighting , enhanced data rates for gsm evolution , phase (matter) , physics , topology (electrical circuits) , mathematical analysis , mathematics , computer science , acoustics , image processing , telecommunications , computer vision , quantum mechanics , combinatorics , image (mathematics)
In this paper, we present edge detection schemes with specially designed superposed spiral phase plate (SSPP) filters in the Fourier domain both for intensity or phase objects. A special SSPP whose function is equivalent to Sobel operator in space domain is firstly designed by weighting different topological charge spiral phase plate (SPP) filters. Later, a SSPP with controllable direction parameters is then discussed to enhance the anisotropic edges by controlling the direction parameter. Numerical simulation and experimental results show that either isotropic or anisotropic edge information can be enhanced by using our proposed schemes. The signal-to-noise ratio and the root-mean-square-error performance are improved in comparison with those using traditional SPP filter. Importantly, it is the first time to present the special ways of superposing and the SSPP can be designed before the experiment so that a clear edge can be achieved at real time without the convolutional operation.