Photonics & Imaging

Lightweight reflector dishes for radio antennas would be mass-produced cheaply by spin casting of polymers, according to a proposal. These reflector dishes were conceived for compact stowage followed by deployment and operation aboard spacecraft, but might also be useful on Earth in...

A retroreflective communication system (RCS), is a state-of-the-art system that provides (1) two-way optical communication using only one transmitter and (2) multipath communication among remote locations. RCSs were conceived for use in communication among stations on the ground and aboard spacecraft in...

An algorithm for filtering synthetic-aperture-radar (SAR) interferograms has been developed which substantially improves the performance of subsequent phase-unwrapping. It accomplishes this task by filtering the interferogram strongly in areas where the scene contains little detail, and weakly where the...

PIVPROC is a computer program for processing data in particle-image velocimetry (PIV), which is a method of determining a flow velocity field from images of small seed particles that are entrained in the flow and that are illuminated by laser pulses at known intervals of time. PIVPROC...

A prototype compact, rugged optomechanical module contains a high-power, wideband laser-diode transmitter. The laser diode is of a commercial single-quantum-well AlGaAs type. Each laser diode of this type is manufactured for a specific nominal wavelength in the range from 810 to 860 nm; the one...

The radial distribution of energy within an image, called encircled energy, is a classical measure of the quality of the optical system producing that image. An improved method for measuring encircled or enclosed energy for imaging optical systems makes use of precisely micromachined...

A proposed automated apparatus would travel along a hanging cable, optically inspecting it all around. The proposal was made to eliminate lowering human inspectors in baskets along emergency-egress slidewires at Kennedy Space Center launch pads. The apparatus would include a motor drive system, a video camera...

An optical sensor for measuring the partial pressure of dissolved oxygen in water is based on the effect of oxygen quenching on the fluorescence lifetime of an optically excited ruthenium complex immobilized in a recently developed polymer. In the operation of this sensor, the fluorescence...

"Hybrid imaging technology" (HIT) is the name of a discipline in which the advancement of electronic image sensors is pursued via hybridization of charge-coupled-device (CCD) and complementary metal oxide/semiconductor (CMOS) circuitry. The guiding principle of HIT is to combine CCD and CMOS components into units that...

Parallel ultra-low-noise hybrid detectors (PHUDs) are developmental image-detector devices for use in low-power, scientific-grade video cameras. The hybrid nature of a PHUD lies in the incorporation of both charge-coupled-device (CCD) image-detection circuitry and complementary metal...