Advanced Image Intensifier: a 60°field-of-view night vision system with integral electroluminescent display

Technologies for pedestrian safety are increasingly emphasized by Automakers in advance of autonomous driving vehicles. A Night Vision System attached behind the front grille can reduce fatal accidents, especially during the nighttime, however, consumers may hesitate to adopt such systems on account of their high price. High-cost Germanium is used in commercial Night Vision System windows, and therefore replacing it with a cheaper infrared window material can lead to a more affordable system. To achieve this, Zinc Sulfide (ZnS), which has about 70% transmittance in the Long-Wavelength Infrared region of 8~12 μm, was selected for the window substrate material. In this study, we designed, fabricated and characterized a single layer cost-effective anti-reflection coating on a ZnS window substrate using Calcium Fluoride (CaF2). The CaF2 coating was fabricated by E-beam evaporation technique, with Quarter wavelength anti-reflection thickness (QAR). It was characterized by FT-IR, SEM and a thermal camera test module. We found that CaF2 both side coated the ZnS window and exhibited about 10~15% higher transmittance than the ZnS window substrate. In addition the CaF2 coating stably bonded to the ZnS substrate without any internal defects. A thermal camera based window test also showed better detection performance with the CaF2 Coating than a bare ZnS substrate window, which was calculated using the output voltage of the microbolometer thermal sensor.

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HMD digital night vision system for fixed wing fighters

10.1117/12.2018104 ◽

2013 ◽

Author(s):

Bobby D. Foote

Keyword(s):

Vision System ◽

Night Vision

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Flexible method for accurate calibration of large-scale vision metrology system based on virtual 3-D targets and laser tracker

International Journal of Advanced Robotic Systems ◽

10.1177/1729881419893516 ◽

2019 ◽

Vol 16 (6) ◽

pp. 172988141989351

Author(s):

Xi Zhang ◽

Yuanzhi Xu ◽

Haichao Li ◽

Lijing Zhu ◽

Xin Wang ◽

...

Keyword(s):

High Precision ◽

Stereo Vision ◽

Large Scale ◽

Vision System ◽

Calibration Method ◽

Field Of View ◽

Large Field ◽

Laser Tracker ◽

Calibration Target ◽

Pose Tracking

For the purpose of obtaining high-precision in stereo vision calibration, a large-size precise calibration target, which can cover more than half of the field of view is vital. However, large-scale calibration targets are very difficult to fabricate. Based on the idea of error tracing, a high-precision calibration method for vision system with large field of view by constructing a virtual 3-D calibration target with a laser tracker was proposed in this article. A virtual 3-D calibration target that covers the whole measurement space can be established flexibly and the measurement precision of the vision system can be traceable to the laser tracker. First, virtual 3-D targets by calculating rigid body transformation with unit quaternion method were constructed. Then, the high-order distortion camera model was taken into consideration. Besides, the calibration parameters were solved with Levenberg–Marquardt optimization algorithm. In the experiment, a binocular stereo vision system with the field of view of 4 × 3 × 2 m3 was built for verifying the validity and precision of the proposed calibration method. It is measured that the accuracy with the proposed method can be greatly improved comparing with traditional plane calibration method. The method can be widely used in industrial applications, such as in the field of calibrating large-scale vision-based coordinate metrology, and six-degrees of freedom pose tracking system for dimensional measurement of workpiece, as well as robotics geometrical accuracy detection and compensation.

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Automatic Rectification of the Hybrid Stereo Vision System

Sensors ◽

10.3390/s18103355 ◽

2018 ◽

Vol 18 (10) ◽

pp. 3355

Author(s):

Chengtao Cai ◽

Bing Fan ◽

Xin Liang ◽

Qidan Zhu

Keyword(s):

Stereo Vision ◽

Optimization Problem ◽

Vision System ◽

Field Of View ◽

Computation Complexity ◽

Constrained Optimization Problem ◽

Projection Model ◽

Nonlinear Constrained Optimization ◽

Stereo Vision System ◽

Dynamic Hybrid

By combining the advantages of 360-degree field of view cameras and the high resolution of conventional cameras, the hybrid stereo vision system could be widely used in surveillance. As the relative position of the two cameras is not constant over time, its automatic rectification is highly desirable when adopting a hybrid stereo vision system for practical use. In this work, we provide a method for rectifying the dynamic hybrid stereo vision system automatically. A perspective projection model is proposed to reduce the computation complexity of the hybrid stereoscopic 3D reconstruction. The rectification transformation is calculated by solving a nonlinear constrained optimization problem for a given set of corresponding point pairs. The experimental results demonstrate the accuracy and effectiveness of the proposed method.

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