Large-area, uniform light field generated using a galvo scanning system for bi-directional reflectance distribution function measurement

2020 ◽  
Author(s):  
Yinuo Xu ◽  
Yingwei He ◽  
Xufeng Jing ◽  
Xiangliang Liu ◽  
Yangting Fu ◽  
...  
Keyword(s):  
Distribution Function ◽  
Light Field ◽  
Scanning System ◽  
Large Area ◽  
Function Measurement ◽  
Directional Reflectance

Biometric system based on one single large area a-SiC:H p-i-n photodiode

2002 ◽  
Vol 722 ◽  
Author(s):  
M. Vieira ◽  
M. Fernandes ◽  
A. Fantoni ◽  
P. Louro ◽  
R. Schwarz
Keyword(s):  
Modulation Frequency ◽  
Wide Band ◽  
Image Sensor ◽  
Scanning System ◽  
Specific Information ◽  
Sensing Element ◽  
Large Area ◽  
Wide Band Gap ◽  
Scan Time ◽  
Dimensional Simulation

AbstractBased on the Laser Scanned Photodiode (LSP) image sensor we present an optical fingerprint reader for biometric authentication. The device configuration and the scanning system are optimized for this specific purpose.The scanning technique for fingerprint acquisition is improved and the effects of the probe beam size, wavelength and flux, the scan time and modulation frequency on image contrast and resolution will be analyzed under different electrical bias. An optical model of the image acquisition process is presented and supported by a two dimensional simulation.Results show that a trade-off between read-out parameters (fingerprint scanner) and the biometric sensing element structure (p-i-n structure) are needed to minimize the cross talk between the fingerprint ridges and the fingerprint valleys. In the heterostructures with wide band gap/low conductivity doped layers the user-specific information is detected with a good contrast while the resolution of the sensor is around 20 νm. A further increase in the contrast is achieved by slightly reverse biasing the sensor with a sensitivity of 6.5 νWcm-2 and a flux range of two orders of magnitude.

Beam scanning system for the uniformity of implanted doses in a large area

1996 ◽  
pp. 267-269
Author(s):  
P. Desgardin ◽  
E. Ntsoenzok ◽  
J.F. Barbot ◽  
J. Briaud ◽  
J. Vernois ◽  
...  
Keyword(s):  
Scanning System ◽  
Large Area ◽  
Beam Scanning

scholarly journals Estimating Underwater Light Regime under Spatially Heterogeneous Sea Ice in the Arctic

2018 ◽  
Vol 8 (12) ◽  
pp. 2693 ◽  
Author(s):  
Philippe Massicotte ◽  
Guislain Bécu ◽  
Simon Lambert-Girard ◽  
Edouard Leymarie ◽  
Marcel Babin
Keyword(s):  
Sea Ice ◽  
Water Column ◽  
Attenuation Coefficient ◽  
Vertical Profile ◽  
Light Field ◽  
Incident Light ◽  
Single Point ◽  
The Arctic ◽  
Large Area ◽  
Average Irradiance

The vertical diffuse attenuation coefficient for downward plane irradiance ( K d ) is an apparent optical property commonly used in primary production models to propagate incident solar radiation in the water column. In open water, estimating K d is relatively straightforward when a vertical profile of measurements of downward irradiance, E d , is available. In the Arctic, the ice pack is characterized by a complex mosaic composed of sea ice with snow, ridges, melt ponds, and leads. Due to the resulting spatially heterogeneous light field in the top meters of the water column, it is difficult to measure at single-point locations meaningful K d values that allow predicting average irradiance at any depth. The main objective of this work is to propose a new method to estimate average irradiance over large spatially heterogeneous area as it would be seen by drifting phytoplankton. Using both in situ data and 3D Monte Carlo numerical simulations of radiative transfer, we show that (1) the large-area average vertical profile of downward irradiance, E d ¯ ( z ) , under heterogeneous sea ice cover can be represented by a single-term exponential function and (2) the vertical attenuation coefficient for upward radiance ( K L u ), which is up to two times less influenced by a heterogeneous incident light field than K d in the vicinity of a melt pond, can be used as a proxy to estimate E d ¯ ( z ) in the water column.

Design of Light-Small Mobile 3D Laser Measurement System

2013 ◽  
Vol 405-408 ◽  
pp. 3032-3036
Author(s):  
Yi Bo Sun ◽  
Xin Qi Zheng ◽  
Zong Ren Jia ◽  
Gang Ai
Keyword(s):  
Point Cloud ◽  
Laser Scanning ◽  
Laser Scanner ◽  
Digital Camera ◽  
Scanning System ◽  
Point Cloud Data ◽  
3D Laser Scanning ◽  
Large Area ◽  
Cloud Data ◽  
Laser Scanning System

At present, most of the commercial 3D laser scanning measurement systems do work for a large area and a big scene, but few shows their advantage in the small area or small scene. In order to solve this shortage, we design a light-small mobile 3D laser scanning system, which integrates GPS, INS, laser scanner and digital camera and other sensors, to generate the Point Cloud data of the target through data filtering and fusion. This system can be mounted on airborne or terrestrial small mobile platform and enables to achieve the goal of getting Point Cloud data rapidly and reconstructing the real 3D model. Compared to the existing mobile 3D laser scanning system, the system we designed has high precision but lower cost, smaller hardware and more flexible.

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