Radial mask for imaging systems that exhibit high resolution and extended depths of field

Abstract

A novel algorithm for the design of an imaging system that exhibits high resolution as well as extended depth of field is presented. This novel approach searches for an optimal pupil mask that minimizes the value of the mean-square error when performed over the intensity rather than in the field distribution of the acquired image. The captured images in such system do not require any postprocessing, and thus utilization of such a system is simplified. Simulations as well as experimental results are provided.

Tunable extended depth of field using a liquid crystal annular spatial filter

“…Finally, a binary mask was constructed in which all rings are 0 but rings 6 and 8 are set to π. This mask is similar to the binary mask suggested by [1] designated "Binary." The choice of the masks was done according to simulations of a similar aberration-free system observing a 16 mm height "staircase" object.…”

“…Increasing the NA improves the system's resolution, however at the cost of lowering the DOF. In recent years many methods were suggested to bypass this problem by adding proper pupil phase masks to provide extended depth of field (EDOF) with sufficient resolution [1][2][3][4][5][6][7]. EDOF implementation may be "all-optical" or supported by image processing.…”

Holistic optical-digital hybrid-imaging design:wide-field reflective imaging

“…Pupil-phase modulation is introduced by modulation of the primary mirror surface with the purpose of enabling mitigation of off-axis imaging aberrations across the full field of view and for object positions between 250 mm and infinity. Here we model the surface modulation as a linear combination of Zernike polynomials that covers the antisymmetric generalized cubic modulations, reported for their aberration mitigating properties [8,[16][17][18]; however, other modulations could be considered as well [7,[19][20][21][22][23]. The generalized cubic modulation is defined as px; y αx 3 y 3 βx 2 y xy 2 , where x and y are normalized Cartesian pupil coordinates.…”

Phase mask selection in wavefront coding systems: A design approach

“…Caron [12] reports an iterative method for optimizing polynomial phase masks (both shape and strength) based on the evaluation of the resultant Modulation Transfer Function (MTF) of the optical system. Other alternatives [13][14][15] have been reported whose general purpose is to extend the DOF through optimizing the pupil phase modulation, though they are aimed at all-optical imaging systems.…”