Author Affiliations
Abstract
1 Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong, China
2 Institute of Applied Physics, University of Electronic Science and Technology of China, 610054 Chengdu, China
In optical scanning holography, one pupil produces a spherical wave and another produces a plane wave. They interfere with each other and result in a fringe pattern for scanning a three-dimensional object. The resolution of the hologram reconstruction is affected by the point spread function (PSF) of the optical system. In this paper, we modulate the PSF by a spiral phase plate, which significantly enhances the lateral and depth resolution. We explain the theory for such resolution enhancement and show simulation results to verify the efficacy of the approach.
Digital holography Digital holography Computational imaging Computational imaging Optical transfer functions Optical transfer functions Photonics Research
2016, 4(1): 01000001
Author Affiliations
Abstract
College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha, 410073, China
In order to select a suitable spatial filter for the spatial filtering velocimeter, the filtering characteristics of the spatial filters with a rectangular window and rectangular transmittance are investigated by the power spectrum of transmittance function method. The filtering characteristics of differential filters are investigated and compared with that of common ones. The influences of the number of spatial periods on the spectral bandwidth, deviation to central frequency, and peak transmittance are deeply analyzed. The results show that the influence is due to the form of superposition of the signal components and other components, the pedestal and higher-order components, and the superposition results from the finite size of the spatial filter. According to the results, a method is proposed to compensate for the deviation to central frequency.
070.6110 Spatial filtering 110.4850 Optical transfer functions 050.2770 Gratings Chinese Optics Letters
2015, 13(6): 060702
Author Affiliations
Abstract
1 State Key Laboratory of Remote Sensing Science, Beijing
2 Institute of Remote Sensing Applications, Chinese Academy of Sciences, Beijing 100101
3 School of Geography, Beijing Normal University, Beijing 100875
This paper addresses the estimation of adjacency effect of CBERS-2 image. The adjacency effect influences the digital number (DN) value of a pixel by adding surrounding scattering signals and path scattering signals. Based on the theory of radiation transfer model, a procedure is designed to measure the reflectance from the surface target materials and the materials in a box, which is 1.5 m above the surface to avoid upwelling reflectance. The results show that the adjacency effect varies from visible, near infrared and becomes steady within short infrared wavelength region; the adjacency effect weakens with the increase of distance between testing sites. The adjacency effect of CBERS-2 image is corrected and the quality of the resulting image is improved.
290.4210 Multiple scattering 110.4850 Optical transfer functions 110.2990 Image formation theory 120.4820 Optical systems Chinese Optics Letters
2006, 4(9): 546
