Photonics/Optics

Hand-Held Optoelectronic Particulate Monitors

Data on concentrations and sizes are obtained from diffraction of light.

Optoelectronic instruments are being developed for use in measuring the concentrations and sizes of microscopic particles suspended in air. The instruments could be used, for example, to detect smoke, explosive dust in grain elevators, or toxic dusts in industrial buildings. Like some older, laboratory-bench-style particulate monitors, these instruments are based on diffraction of light by particles. However, these instruments are much smaller; exploiting recent advances in optics, electronics, and packaging, they are miniaturized into compact, hand-held units.

Posted in: Briefs, TSP, ptb catchall, Tech Briefs, Photonics, Physical Sciences, Downsizing, Measurements, Microscopy, Optics, Particulate matter (PM)
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High-Performance Processor of Hyperspectral Images

Efficient algorithms analyze pixel spectra to estimate abundances of materials.

The Remote Sensing Hyperspectral Engine (RSHE) is a special-purpose, portable computer that performs high-performance processing of hyperspectral image data collected by a remote-sensing optoelectronic apparatus. Typically, the remote-sensing apparatus is airborne or spaceborne, the images are of terrain, and the purpose of collecting and analyzing the image data is to estimate the spatially varying abundances of materials of interest. Remote-sensing applications in which the RSHE could prove beneficial include assessment of crops, exploration for minerals, identification of military targets, urban-planning studies, environmental assessment, and large-area search-and- rescue operations.

Posted in: Briefs, Tech Briefs, Photonics, Computer software and hardware, Imaging and visualization, Remote sensing, Data management
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Lateral-Current-Collection HgCdTe Infrared Detectors

Improvements in yield and electrical performance are obtained.

Arrays of HgCdTe infrared photodetectors have been developed to satisfy stringent performance requirements for use in NASA’s Tropospheric Emission Spectrometer. The design of these detectors improves (relative to prior such arrays) manufacturing yield, current-versus-voltage characteristics, and low-temperature performance. The design is of the doublelayer planar heterostructure (DLPH) type but differs from conventional DLPH designs in that it features a distinctive lateral current-collection configuration.

Posted in: Briefs, TSP, ptb catchall, Tech Briefs, Electronics & Computers, Photonics, Sensors and actuators, Spectroscopy, Product development, Performance tests
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Portable Airborne Multispectral-Imaging System

This system can be put into operation almost anywhere on short notice.

A portable instrumentation system that includes an airborne and a ground-based subsystem acquires multispectral image data over swaths of terrain ranging in width from about 1/2 to 1 km. The system was developed especially for use in surveying coastal environments; it is also well suited for performing remote sensing in connection with agriculture, aquaculture, forestry, environmental decontamination, and general environmental monitoring. The system can be stowed in two suitcase-size containers that can be transported as check-in luggage on a commercial airline. Once the system has been delivered to its destination and unstowed, the airborne subsystem can be launched over unprepared terrain and controlled from the ground-based subsystem, which can be operated from a minivan or a similarly sized vehicle.

Posted in: Briefs, ptb catchall, Tech Briefs, Photonics, Imaging and visualization, Remote sensing, Terrain, Test equipment and instrumentation
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Lossless Image-Compression Algorithm Implemented in an FPGA

Compression performance is somewhat better than that of a prior algorithm.

A lossless image-compression algorithm that can be executed entirely in electronic hardware has been developed. This algorithm yields about 15 percent more compression than does the Rice algorithm, which is a lossless-compression algorithm commonly used for transmitting images from spacecraft to Earth. A prototype of the hardware (see figure), consisting mainly of a field-programmable gate array (FPGA) and a small random-access memory, has been built and verified to function as intended.

Posted in: Briefs, TSP, ptb catchall, Tech Briefs, Electronics & Computers, Photonics, Mathematical models, Data exchange, Integrated circuits, Spacecraft
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Hardware and Software for Air-to-Air Schlieren Imaging

Accurate positioning and camera control are necessary for success in schlieren imaging.

Software and electronic hardware are being developed to provide cockpit guidance and camera control for an air-to-air schlieren photography system that is to be used to take high-resolution pictures of shock waves generated by a full-scale airplane (see Figure 1). For success in schlieren imaging, it will be necessary to position two airplanes — an observing airplane and the one generating the shock waves — precisely along a line of sight to the Sun, which will be used for illumination. The shock-wave-generating airplane will fly at supersonic speed, while the observing airplane will have to fly at a much lower speed of 250 knots (129 m/s).

Posted in: Briefs, ptb catchall, Tech Briefs, Photonics, Computer software and hardware, Electronic equipment, Optics, Human machine interface (HMI), Test equipment and instrumentation, Hypersonic and supersonic aircraft
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Fractal-Based Encryption

Encryption methods based upon nonprobabilistic nondeterminism show promise in the optical age.

In 1987 a discovery led to the formal proof that it is possible to use chaotic functions to arrive at a nonprobabilistic and nondeterministic method normal context of the operation of this system, and by using a virtual operational environment, the investigators are manipulating data in eight dimensions, which require a sixty-four discrete coordinate system, using eight nominative octets. Each octet is further addressed using the characters 0 through 9, and lower- or upper-case letters from A to Z. These provide the ability to address using normal ASCII characters. This format was chosen to ensure backward and forward compatibility with external third-party-written software.

Posted in: Briefs, ptb catchall, Tech Briefs, Photonics, Mathematical analysis
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Camera Images Hydrogen Fires in Three Wavelength Bands

The camera filters and processing can be customized for other multispectral imaging applications.

A special-purpose multispectral video camera has been designed to provide an enhanced capability for viewing hydrogen fires. Hydrogen fires do not emit sufficient visible light to be seen by the unaided human eye, but they do emit strongly at other wavelengths — especially in the infrared and near-infrared portions of the spectrum. Therefore, like some other video cameras developed previously for the same purpose, this camera is designed to respond to infrared light emitted by hot water molecules in hydrogen flames. Going beyond previous designs, this camera provides a combination of imaging in three wavelength bands and processing of the three images, all for the purposes of (1) reducing spurious responses to background light and solar radiation, and (2) synthesizing an image of a hydrogen flame overlaid on an ordinary visible-light image of the scene that contains the flame.

Posted in: Briefs, ptb catchall, Tech Briefs, Photonics, Optics, Hydrogen fuel, Fire
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Video-Based Foreign Object Detection

The technique can be applied to any assembly process where inclusion of foreign material can cause harm.

The Boeing Company has developed an overhead camera system that can automatically spot small pieces of debris on a work surface that might otherwise go unnoticed. The system automatically analyzes inputs from one or more video cameras to detect undesirable colors representing materials that, if left in place, would degrade part quality. The system uses commercial off-the-shelf hardware and software for low-cost implementation and is currently in use in the Boeing F/A-18 wing production line (see figure). The patent-pending technology, known as foreign-object video detection and alert system and method, is available for license.

Posted in: Briefs, ptb catchall, Tech Briefs, Photonics, Optics, Manufacturing equipment and machinery, Inspections
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