Optical experimental results using Singer product apertures.

We present the first optical experimental results obtained using the recently developed Singer product apertures. We also show that Fenimore and Cannon's fine sampling and delta decoding techniques can be combined with the fast direct vector decoding algorithm for Singer product apertures. We demonstrate resolutions and decoding speeds comparable to, or better than, those currently reported in the optical literature. Taken together these make possible coded aperture video in the optical domain.

Contiguous perfect coded aperture patterns with high throughput.

A method is described that mosaics linear uniformly redundant arrays and modified uniformly redundant arrays onto a square lattice to create coded aperture patterns of approximately 50% throughput that are contiguous, whereby every opaque element in the aperture is joined to at least one other opaque element. Parameters required to create these perfect high-throughput contiguous apertures for all coded aperture unit pattern orders of up to 300 elements are presented. The apertures presented increase significantly the number of known contiguous apertures in dimensions forbidden to the known patterns and that have the same imaging quality as uniformly redundant arrays and modified uniformly redundant arrays while having imaging quality superior to other known self-supporting apertures. The effect of supporting the weaker areas of these contiguous apertures is investigated. Contiguous apertures are of interest for coded aperture systems that require extra rigidity or use active collimation.

Fast decoding algorithm for Gourlay-Young coded apertures.

A fast decoding algorithm is described for the class of flexible coded-aperture designs introduced by Gourlay and Young [Appl. Opt.23, 4111 (1984)APOPAI0003-693510.1364/AO.23.004111]. The algorithm significantly reduces the number of mathematical operations required to perform the decoding of images produced using these apertures compared to currently known methods, such as direct decoding, and hence speeds up the image reconstruction. Experimental tests confirm the efficacy of the fast decoding algorithm, which offers a speed-up enabling a typical 120×120 element aperture to be decoded in around 1% of the time required for direct decoding.

Index class apertures--a class of flexible coded aperture.

A class of flexible coded apertures, called index class apertures, is presented. The configurations are shown to possess similar properties to the geometric apertures of Gourlay and Stephen [Appl. Opt.22, 4042 (1983)], and it is demonstrated that the modified uniformly redundant arrays (MURAs) are a special case of the index class apertures. The apertures are shown to offer both a larger range of throughput values and better imaging capability than is available to the geometric apertures, while at the same time possessing more rigidity of structure than other designs, such as the MURAs and the uniformly redundant arrays.