Direct TOF Scanning LiDAR Sensor With Two-Step Multievent Histogramming TDC and Embedded Interference Filter

Early in the 1950's Strömgren (1, 2, 3, 4, 5) introduced medium to narrow-band interference filter photometry at the McDonald Observatory. He used six interference filters to obtain two parameters of astrophysical interest. These parameters he calledlandc, for line and continuum hydrogen absorption. The first measured empirically the absorption line strength of Hβby means of a filter of half width 35Å centered on Hβand compared to the mean of two filters situated in the continuum near Hβ. The second index measured empirically the Balmer discontinuity by means of a filter situated below the Balmer discontinuity and two above it. He showed that these two indices could accurately predict the spectral type and luminosity of both B stars and A and F stars. He later derived (6) an indexmfrom the same filters. This index was a measure of the relative line blanketing near 4100Å compared to two filters above 4500Å. These three indices confirmed earlier work by many people, including Lindblad and Becker. References to this earlier work and to the systems discussed today can be found in Strömgren's article inBasic Astronomical Data(7).

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High Purity ZnS/Ge Interference Filter Emittance

10.21236/ada376584 ◽

1999 ◽

Author(s):

Russel E. Clement ◽

Clyde Elliott ◽

Jon Fisher

Keyword(s):

High Purity ◽

Interference Filter

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Evaluation of the expediency of using thermal i magery data for decryption exogenous processes and vegetation

Geodesy and Cartography ◽

10.22389/0016-7126-2018-933-3-52-62 ◽

2018 ◽

Vol 933 (3) ◽

pp. 52-62

Author(s):

V.S. Tikunov ◽

I.A. Rylskiy ◽

S.B. Lukatzkiy

Keyword(s):

Spatial Data ◽

Laser Scanning ◽

Data Extraction ◽

Spectral Band ◽

Information Provision ◽

Lidar Data ◽

Thermal Imagery ◽

Scanning Lidar ◽

Field Works ◽

Object Features

Innovative methods of aerial surveys changed approaches to information provision of projecting dramatically in last years. Nowadays there are several methods pretending to be the most efficient for collecting geospatial data intended for projecting – airborne laser scanning (LIDAR) data, RGB aerial imagery (forming 3D pointclouds) and orthoimages. Thermal imagery is one of the additional methods that can be used for projecting. LIDAR data is precise, it allows us to measure relief even under the vegetation, or to collect laser re-flections from wires, metal constructions and poles. Precision and completeness of the DEM, produced from LIDAR data, allows to define relief microforms. Airborne imagery (visual spectrum) is very widespread and can be easily depicted. Thermal images are more strange and less widespread, they use different way of image forming, and spectral features of ob-jects can vary in specific ways. Either way, the additional spectral band can be useful for achieving additional spatial data and different object features, it can minimize field works. Here different aspects of thermal imagery are described in comparison with RGB (visual) images, LIDAR data and GIS layers. The attempt to estimate the feasibility of thermal imag-es for new data extraction is made.

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Biaxial 360-degree scanning LIDAR using a liquid crystal control

Scientific Reports ◽

10.1038/s41598-021-94208-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Seiji Nishiwaki

Keyword(s):

Liquid Crystal ◽

Laser Light ◽

Side Surface ◽

Parallel Beam ◽

Grating Couplers ◽

Autonomous Cars ◽

Scanning Lidar ◽

Center Axis ◽

Circular Grating ◽

Segmented Electrode

AbstractSophisticated non-mechanical technology for LIDARs is needed to realize safe autonomous cars. We have confirmed the operating principle of a non-mechanical LIDAR by combining concentric circular-grating couplers (CGCs) with a coaxially aligned rod lens. Laser light incident vertically on the center of the inner CGC along the center axis of the lens is radiated from the outer CGC and passes through the side surface of the lens. It is converted to a parallel beam that scans in two axes by applying voltages to two area-segmented electrode layers sandwiching the CGCs and a liquid crystal layer formed on the CGCs. We have demonstrated scanning whose motion ranges were 360 degrees horizontally and 10° vertically. A beam with a spread angle of 0.3° × 0.8° at a minimum swept vertically up to a frequency of 100 Hz and ten equally spaced beams scanned rotationally with a 6-degree cycle variation of spread of between 0.8° and 3.5°.

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