Open AccessImage edge enhancement using Airy spiral phase filter
Author(s) -
Zhou Yi,
Shuai Feng,
Shouping Nie,
Jun Ma,
Yuan Chen
Publication year - 2016
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.24.025258
Subject(s) - optics , side lobe , spiral (railway) , phase (matter) , physics , main lobe , edge enhancement , isotropy , filter (signal processing) , amplitude , enhanced data rates for gsm evolution , spatial filter , radius , position (finance) , image processing , mathematics , image (mathematics) , telecommunications , computer science , mathematical analysis , computer security , quantum mechanics , antenna (radio) , computer vision , finance , economics , artificial intelligence
The isotropic and anisotropic image edge enhancements by employing Airy spiral phase filters are proposed and demonstrated. The coherent spread functions of the image systems are derived from transmittance functions of their corresponding filters. In the isotropic method, the distributions of the coherent spread function with the radius of the main ring ρ 0 and the scaled parameter w 0 are numerically analyzed. It is found that the width of the main lobe determining the resolution decreases with the increased ρ 0 , and the amplitudes of the side lobes connecting with the contrast fluctuate with w 0 . Compared with the existing spiral phase filters, higher contrast and resolution can be achieved by adjusting the two parameters in the Airy spiral phase filter. Moreover, an off-axis Airy spiral phase filter by controlling the center position (ρ 0 ,ϕ 1 ) is designed and employed to implement anisotropic edge enhancement. In the experiments, two methods of image edge enhancement have been verified by using the amplitude-contrast and phase-contrast objects.