Irving J. Spiro

Atmospheric transmission: Concepts, symbols, units and nomenclature

Abstract This report discusses concepts, symbols, units and nomenclature for describing the transmission of radiant flux through the earths (variably density) atmosphere.

The optimization of an optical missile guidance tracker.

An antitank missile guidance system is described, which employs a tracker using two parallel optical paths and a pyrotechnic flare. Both optical channels are spectrally filtered; one rejects the target and views only the flare image; the other rejects the flare and views only the target. In performing the guidance tracking task, the operator superimposes the flare image on the target, thus providing steering signals to the missile. This paper describes an optimum flare as one with maximum luminous spectral emittance, minimum bandwidth, and minimum noise. Then with the selected flare as a basis, the optical components are matched individually and as an assembly to obtain maximum flare-filter system output. Calculated improvements of 100 to 250% were obtained in the performance of critical components which were reflected in the system operation and were subsequently verified by system field tests. The transmission ratios, visibility coefficients, improvement factors, and other bases for improvement are stated and discussed. Finally, the experiments performed and improvements achieved are described.

Improved Schottky Array Performance With Lenticulated Faceplate

Laboratory evaluation is provided of the improved focal plane array performance realized with a novel optical technique that increases the fill factor of Schottky IRCCD mosaics. Specifically, a lenticulated silicon faceplate is installed on the IRCCD chip to redirect focused image irradiance away from nonsensitive areas in the focal plane and to the infrared-sensitive elements. A technique has been developed for successfully fabricating these optical faceplates with the necessary geometrical requirements. The performance data contained herein were obtained with an RCA-supplied 32 x 63 Schottky IRCCD mosaic having a lenticulated faceplate installed on a portion of the array surface. The adjacent dual construction allowed sensitivity and resolution differences to be easily evaluated under identical operating conditions. The enhanced performance was determined experimentally and then compared to predicted fill-factor improvement.

Guest Editorial Critical Technology: Infrared Optics

This special issue on Infrared Optics is the first of what we expect will be an annual issue and an Optical Engineering tradition. Included in this issue are papers on the design and testing of infrared optical systems and components, including lenses, mirrors, coatings, and filters.

Optical Technique For Increasing Fill Factor Of Mosaic Arrays

A novel optical technique for improving the performance of focal plane staring arrays by increasing the fill factor ratio is described. The specific mosaics considered are 64 x 32 and 128 x 64 Schottky barrier infrared detectors with charge coupled devices (IRCCD) made from monolithic silicon. The video enhancement is accomplished by means of a refracting silicon faceplate that redirects focused image irradiance from nonsensitive CCD areas to the infrared detector elements. Operational theory and design parameters for this unique faceplate construction are detailed. With the optimum faceplate configuration installed at the IRCCD front surface, a sensitivity increase of at least .200 percent is predicted from the analysis presented here.

Parametric Studies Of Space Infrared Sensors

The equations used for system infrared calculations are presented. These equations are then rearranged into the forms useful for developing space infrared systems. In the paper, curves and nomograms are presented that exhibit the relationships between many parameters such as detector sizes, diameter of the optics, focal lengths of the optics, ground footprint, D* , angular resolution, target intensity, and quantum efficency

Editorial, Forum and Book Reviews

Review of the Sixth (1980) Annual SPIE Seminar on Modern Utilization of Infrared Technology My column this month is a review of the sixth annual seminar on Modern Utilization of Infrared Technology, which was held at the Town & Country Hotel, San Diego, on 31 July to 1 August 1980. The seminar was divided into four sessions:

Infrared Astronomy Instruments

In this issue devoted to Infrared Astronomy Instruments, you will note that most of the instruments are designed for use at altitude, either in aircraft, balloons, probes or satellites. Such usage permits observation above the interfering atmosphere usually encountered during ground observations. Most of the water vapor is below the platform at 40,000 feet (~13 km) and most of the CO2 is below platforms at 120,000 feet (~40 km).

Symbols, Units and Nomenclature for Atmospheric Transmission

This report discusses concepts, symbols, units and nomenclature for describing the transmission of radiant flux through earths variable density atmosphere. The geometrical concepts used in the field of photometry and radiometry are the same. A common set of symbols is proposed for use in both fields together with some terms not previously used.

Image Motion and Resolution For Air-To-Air Photography

The resolution and blur due to image motion for air-to-air photography are discussed. Analyses involving range, relative velocities, miss distances, focal lengths, exposure times, angular rates and lens-film resolution capabilities are presented, Equations are derived for resolution and image blur due to linear and/or angular motions. Curves and nomograms are presented which permit determination of the parameters.