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Hui M.,Beijing Institute of Technology | Hui M.,Beijing Key Laboratory for Precision Optoelectronic Measurement Instrument and Technology | Zhou P.,University of Arizona | Su P.,University of Arizona | And 2 more authors.
Applied Optics | Year: 2015

Lenslet array was introduced to an image detector to compensate for low sensitivity. These lenses deviate the light from different incident angles and potentially introduce errors when subpixel accuracy is needed. We investigated the spot centroid position because the angle of incidence changes on a Kodak KAI-16000 image detector with lenslet array. In our experiment, we noticed that there is a cubic dependency on the incident angle. The experimental results show that dependence on the angle of incidence is related to the lenslet array in the Kodak detector used for the pentaprism test. This situation caused an error in spherical aberration on the test surface after integration. The magnitude of the cubic component at incident angle of 14° (equivalent to F/2) is 11.6 μm, which corresponds to a 48 nm rms spherical aberration for the test surface and brings the scanning pentaprism test closer to the principal test while there is a 56 nm rms discrepancy. The discrepancy in spherical aberration between the two tests reduced to 8 nm after this calibration. It also showed the contrast measurement results for the Kodak detector and PointGrey detector. We performed experiments with two different detectors to quantify this effect. © 2015 Optical Society of America. Source


Gao M.,Beijing Institute of Technology | Gao M.,Beijing Key Laboratory for Precision Optoelectronic Measurement Instrument and Technology | Lan T.,Beijing Institute of Technology | Lan T.,Beijing Key Laboratory for Precision Optoelectronic Measurement Instrument and Technology | And 4 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2015

Optical receiving antenna is usually positioned before the detector of an indoor visible light communication (VLC) system in order to collect more optical energy into the detector. Besides optical gain of the antenna, the field of view (FOV) plays also an important role to the performance of a VLC system. In this paper, the signal noise ratio (SNR) and inter-symbol interference (ISI) versus FOV of the antenna are simulated via Line-of-Sight (LOS) and non-Line-of-Sight (NLOS) links within a room with a size of 5m × 5m × 3m. Results show that, the blind area appears while the FOV is less than 40 deg. and the SNR reduces as FOV increases and keeps small when FOV is more than 70 deg. Furthermore, the average power of ISI rises with the increase of FOV, and the rising trend is relatively moderate when FOV is below 50 deg., while there is a rapid increase between 50 deg. and 70 deg. and finally tends to be stable after 70 deg. Therefore, it is practical to determine the FOV of the optical receiving antenna in the scope of 40 to 50 deg. based on the installment of LED lights on the ceiling here so as to avoid the blind area, attain high SNR, and reduce the influence of ISI. It is also worthwhile in practice to provide an identifiable evidence for the determination of FOV of the optical antenna. © COPYRIGHT 2015 SPIE. Source


Wang X.,Beijing Institute of Technology | Wang X.,Beijing Key Laboratory for Precision Optoelectronic Measurement Instrument and Technology | Lv L.,Beijing Institute of Technology | Lv L.,Beijing Key Laboratory for Precision Optoelectronic Measurement Instrument and Technology | And 11 more authors.
Optical Engineering | Year: 2013

Abstract. An infrared (IR, 3-5 and 8-12 ?m)/microwave (MW, 2.7 GHz) micromirror array type of beam combiner was fabricated for test and analysis. A model based on transmission line theory, Snells law, and phase monopulse radar theory was built to analyze the boresight angle errors. Three types of boresight angle errors-inherent error, refraction-induced error and combiner inserting error-were calculated. The results indicated that combiner inserting error was the most important error. Using this theoretical model, a beam combiner was optimized, fabricated, and investigated experimentally. Measured by a phase monopulse radar, the boresight angle error introduced by the beam combiner was 0.1 deg, which coincided with the theoretical calculations. Infrared images were reflected by the beam combiner, the angular resolution of the reflected images in azimuth, and elevation directions were 40 and 80 in., respectively. © 2013 Society of Photo-Optical Instrumentation Engineers (SPIE). Source


Xu R.,Beijing Institute of Technology | Xu R.,Beijing Key Laboratory for Precision Optoelectronic Measurement Instrument and Technology | Wang X.,Beijing Institute of Technology | Wang X.,Beijing Key Laboratory for Precision Optoelectronic Measurement Instrument and Technology | And 5 more authors.
Applied Optics | Year: 2016

In order to test a direct-detection ladar in a hardware-in-the-loop simulation system, a ladar scene projector is proposed. A model based on the ladar range equation is developed to calculate the profile of the ladar return signal. The influences of both the atmosphere and the target's surface properties are considered. The insertion delays of different channels of the ladar scene projector are investigated and compensated for. A target range image with 108 pixels is generated. The simulation range is from 0 to 15 km, the range resolution is 1.04 m, the range error is 1.28 cm, and the peak-valley error for different channels is 15 cm. © 2016 Optical Society of America. Source


Tian Y.,Beijing Institute of Technology | Tian Y.,Shanghai Institute of Electro Mechanical Engineering | Tian Y.,Beijing Key Laboratory for Precision Optoelectronic Measurement Instrument and Technology | Sun G.,Beijing Institute of Technology | And 7 more authors.
Applied Optics | Year: 2014

The design method of an infrared/millimeter wave mirror array type of beam combiner was investigated. The beam combiner was composed of a support plate, air gap, and mirror array. It had two advantages: one was that the size of the beam combiner could beextended bysplicing more mirrors; the other was that the millimeter wave passband could be tuned by adjusting the thickness of the air gap. The millimeter wave and infrared structure was designed by using transmission line theory and optimized by a simplex Nelder-Mead method. In order to analyze the influence of deformation on performance, the mechanical characteristics of the mirrors and support plate were analyzed by the finite element method. The relationship between the millimeter wave transmission characteristics and the air gap was also analyzed by transmission line theory. The scattered field caused by pillars was computed by the multilevel fast multipole method. In addition, the effect of edge diffraction on the near field uniformity was analyzed by the aperture field integration method. In order to validate the mirror array splicing principle and the infrared imaging performance, a prototype of the mirror array was fabricated and tested. Finally, the infrared images reflected by the mirror array were obtained and analyzed. The simulation and experiment results validated the feasibility of the mirror array beam combiner. © 2014 Optical Society of America. Source

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