Extended axial irradiances: Barker rings.

For extending focal depth we employ a set of transparent concentric rings, which are coded with the Barker sequences of length L. At the neighborhood of the paraxial focal plane, these transparent masks generate an axial uniform distribution, which is modulated with sinusoidal variations. For imaging applications, one can extend focal depth if the Barker length is congruent to unity modulo 4.

Reducing field depth: annular Hadamard masks.

For optically narrowing field depth, we explore the use of annular masks that are coded with the elements of Hadamard matrices. We show that with no further reduction of light throughput, these annular masks can enhance the influence of focus error on the modulation transfer functions (MTF). We report numerical evaluations of the irradiance point spread functions (PSFs), their associated MTFs, and of some digitally generated images.

A Fast Image Dehazing Algorithm Using Morphological Reconstruction.

Outdoor images are used in a vast number of applications, such as surveillance, remote sensing, and autonomous navigation. The greatest issue with these types of images is the effect of environmental pollution: haze, smog, and fog originating from suspended particles in the air, such as dust, carbon and water drops, which cause degradation to the image. The elimination of this type of degradation is essential for the input of computer vision systems.

Pseudo-random masks for angular alignment.

We present an alignment technique that exploits angular correlations by employing a pair of masks, which encode in an angular format pseudo-random sequences. The angular correlator generates peaked irradiance distributions on-axis, provided that the elements of the pair are aligned. Otherwise, the on-axis irradiance distribution decreases to a minimum value.

Hadamard circular masks: high focal depth with high throughput.

We present a class of binary masks that encode, in polar coordinates, the values of a Hadamard matrix of order N. For order N ≥ 2, the binary masks increase the Strehl ratio vs. focus error by the factor N, with the highest possible light throughput.