Imaging

Linear Fresnel Spectrometer Chip with Gradient Line Grating

A very small spectrometer was created by integrating a differential linear Fresnel lens onto an imaging chip.

NASA's Langley Research Center has built a very small spectrometer by integrating a differential linear Fresnel lens onto an imaging chip. NASA is using the lens/chip in a very small spectrometer that will be mounted on the tires of a rover to analyze soil on the Moon or Mars. The spectrometer is useful for space-constrained applications. It combines good resolution with small size and potentially reduced manufacturing costs. The ultra-compact integration of the spectrometer is enabled by the use of an optimized Fresnel grating. Since Fresnel imaging works as valid focal points of spectrum within the short optical distance, the shorter optical path length required (compared to a traditional Fraunhofer lens) enables the small size. Further, the evolution to a differentially linear Fresnel lens (instead of circular Fresnel) avoids the need for aperture slit driver electronics and moving parts, and simplifies manufacturing. The linear Fresnel gratings lend themselves to mass production via plastic injection molding or nano-imprint lithography. NASA is seeking partners to develop the spectrometer for commercial applications.

Posted in: Briefs, Imaging
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Machine Vision System

This system rapidly recognizes and locates surface shapes in range images.

A number of instruments have been built to obtain range images — a two-dimensional array of numbers that gives the depth of a scene along many directions from a central point in the instrument. Instead of measuring the brightness of many points in a scene, as in a television camera, these instruments measure where each point is in a three-dimensional space. Both range images and the more conventional intensity images from digital cameras have been used in the computer vision research community to determine the pose of observed objects or surface shapes. “Pose” refers to a complete description of an object's position and orientation. For a rigid object, this requires six numbers — such as X, Y, Z, pitch, yaw, and roll — or six equivalent coordinates. The previous methods for pose estimation all suffer from either a lack of generality or from time inefficiency.

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Lock-In Imaging System for Detecting Disturbances in Fluid

The aircraft-based technology can detect irregular motion of transparent air.

NASA's Langley Research Center has developed an aircraft-based turbulence and vortex detection system. Turbulence and vortices in the front-flight path are very dangerous for airplanes. Especially when an airplane is approaching the airfield to land, the altitude near the airfield is very low, and the vortices and air turbulence near the ground can cause the airplane to become unstable. Because the vortices and turbulence are just an irregular motion of transparent air, visual detection is very difficult. The NASA Langley invention is designed to detect the irregular motion of transparent air in the front-flight path from a few hundred meters to kilometers.

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Curved Sensor Improves Image Quality Captured with Digital Cameras

This sensor demonstrates significantly sharper images and a practical approach for curving off-the-shelf image sensors.

In dark environments, it is often difficult to get a clear, high-quality image. To address this problem, a method was developed for spherically curving the flat image sensors found in digital cameras. The curved sensors could be used to create better cameras for surveillance, head-mounted displays, and advancements in autonomous vehicle navigation.

Posted in: Briefs, Imaging
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Algorithm Enables Five-Dimensional Imaging in Living Organisms

This technique is faster, less expensive, and more accurate than current methods, and works with cellphone images.

Researchers use fluorescent imaging to locate proteins and other molecules in cells and tissues by tagging the molecules with dyes that glow under certain kinds of light — the same principle behind “black light” images. Fluorescent imaging can help scientists and researchers understand which molecules are produced in large amounts in cancer or other diseases. This information may be useful in diagnosis or in identifying possible targets for therapeutic drugs.

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Microstructural Explorations Inside Fuel Cells

Solid oxide fuel cells (SOFCs), a promising technology that can efficiently produce energy using fossil fuels with no moving parts and low emissions, present a particularly perplexing economic challenge: current systems operate at maximum efficiency between 700 and 1000 degrees Celsius, but such high temperatures shorten their service life, requiring more frequent fuel cell stack replacements. Lowering the operating temperature makes them last longer, but requires additional cells in the stack to deliver the same performance, and that drives up costs.

Posted in: Briefs, Imaging, Photonics, Emissions control, Fuel cells, Thermodynamics, Thermodynamics, Durability, Reliability, Durability, Reliability
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The Advanced Land Imager Helped NASA Mission Exceed Expectations.

After more than 16 years of operation, NASA’s Earth Observing–1 (EO-1) spacecraft was decommissioned on March 30 of this year. The Advanced Land Imager (ALI) developed by MIT Lincoln Laboratory was aboard as an alternative to the land-imaging sensor that was used by the Landsat Earth-observing program.

Posted in: Briefs, Imaging, Photonics, Architecture, Imaging, Imaging and visualization, Architecture, Imaging, Imaging and visualization, Satellites, Spacecraft
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Device and Method of Scintillating Quantum Dots for Radiation Imaging

Potential applications include medical imaging and aircraft inspection.

NASA’s Langley Re search Center has developed Scintillating Quantum Dots for Imaging X-rays (SQDIX) technology that enables the creation of x-ray detectors that are more sensitive than current x-ray detectors. In addition to superior sensitivity, SQDIX also offers the promise of reducing the cost of x-ray detectors by at least a factor of 10. Simply stated, SQDIX has the potential to change the way that x-ray detection is done.

Posted in: Briefs, Imaging, Sensors, Performance upgrades, Product development, X-ray inspections
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CUDA Framework for Linear Time-Invariant Control of Adaptive Optics Systems

The predictor used here is computed directly from a measured open-loop disturbance sequence using an efficient subspace identification algorithm.

Current science objectives, such as high-contrast imaging of exoplanets, have led to the development of high-order adaptive optics (AO) systems possessing several thousand deformable mirror (DM) actuators. These systems typically rely on integrator-based control architectures, where the temporal error rejection bandwidth is limited by the computational latency between wavefront measurement and application of the DM commands. In many systems, this latency is the driving factor behind residual wavefront error.

Posted in: Briefs, Imaging, Optics, Photonics, Mirrors, Adaptive control, Architecture, Optics, Adaptive control, Architecture, Optics
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Invertible Time Invariant Linear Filtering (InTILF) Method for Pattern Detection and Modeling of Stochastic One- or Two-Dimensional Data

This tool can analyze and model surface metrology data for polishing-tool fabricators.

X-ray astronomy offers the opportunity to observe important phenomena, including the early accretion of massive black holes and detecting diffuse ionized intergalactic gas that is heated to X-ray temperatures (>106). One of the technical challenges facing X-ray astronomy is fabricating optics that are properly shaped and smooth enough to produce quality images. Surface defects on the order of the wavelength of the observed spectrum and up to the size of the optical surface must be polished out of the mirrors without leaving a detectable pattern because the detectable signal is on the order of magnitude of the noise. This leads to a cycle of polishing and metrology that adds time and expense to optics fabrication.

Posted in: Briefs, Imaging, Photonics, Imaging, Imaging and visualization, Optics, Imaging, Imaging and visualization, Optics, Fabrication, Radiation
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