Overall structure of the infrared target simulator system and the principle of DMD are introduced. When DMD is on “open” state, all of the incidence light can rip into the pupil of the projection system. In addition, when it is on “close” state or “flat” state, all of the incident light can’t rip into the pupil of the projection system. Based on this principle, with a specific infrared target simulator, TIR prism with BaF2 as material is designed. And then, this design is improved by ZnSe material instead of BaF2. ZnSe transmission rate is very well in the range of 0.6 microns to 14 microns and the infrared target simulator in this project requires 3 to 5 microns and 8 to 14 microns wavelength. This material is hard and easy to be processed. The design idea and design process are introduced in details in this paper and angle parameters are obtained. To improve light utilization and image quality in infrared target simulator system, two types of thin film on TIR prism different surfaces are designed. One is high transmittance with incidence angle of 0° and 24°，the other is 55°. Finally, this scheme is simulated and optimized by Tracepro software. Approving results were acquired.
The design of the collimator for dynamic infrared (IR) scene simulation based on the digital micro-mirror devices (DMD) is present in this paper. The collimator adopts a reimaging configuration to limit in physical size availability and cost. The aspheric lens is used in the relay optics to improve the image quality and simplify the optics configuration. The total internal reflection (TIR) prisms is located between the last surface of the optics and the DMD to fold the raypaths of the IR light source. The optics collimates the output from 1024×768 element DMD in the 8~10.3μm waveband and enables an imaging system to be tested out of 8° Field Of View (FOV). The long pupil distance of 800mm ensures the remote location seekers under the test.
Infrared scene simulation system can simulate multifold objects and backgrounds to perform dynamic test and evaluate EO detecting system in the hardware in-the-loop test. The basic structure of a dual-waveband dynamic IR scene projector was introduced in the paper. The system’s core device is an IR Digital Micro-mirror Device (DMD) and the radiant source is a mini-type high temperature IR plane black-body. An IR collimation optical system which transmission range includes 3～5μm and 8～12μm is designed as the projection optical system. Scene simulation software was developed with Visual C++ and Vega soft tools and a software flow chart was presented. The parameters and testing results of the system were given, and this system was applied with satisfying performance in an IR imaging simulation testing.
With unique working principle and spectral characteristic, the long wave infrared (LWIR) interferometric spectral imaging is a popular technology with wide application in many fields. In order to miniaturize and light the instrument, a new method of LWIR spectral imaging system based on a variable gap Fabry-Perot (FP) interferometer is researched. With the system working principle analyzed, theoretically, it is researched that how to make certain the primary parameter, such as, the reflectivity of the two interferometric cavity surfaces and the wedge angle of interferometric cavity. A prototype is developed and good experimental results of blackbody and polypropylene film are obtained. The research shows that besides high throughput and high spectral resolution, the advantage of miniaturization is also simultaneously achieved in this method.
An acousto-optic tunable filter (AOTF) is an acousto-optic modulator. In this paper, the characteristics and overall
design method of AOTF hyperspectral imaging system are proposed, which operates in visible or near infrared waveband
(0.4-1.0um) and middle wave or long wave (3-5um and 8-12um). Compared with conventional dispersion element, the
AOTF hyperspectral imaging system has a larger clear aperture because of the special characteristic of beam separation
mode. In particularly, if the non-collinear design mode is used, the AOTF will have a larger diffraction aperture angle
and is more suitable for the application in spectral imaging domain. The AOTF hyperspectral imaging spectrometer that
operates in visible/near infrared waveband was developed by the non-collinear TeO2 crystal (8mm×8mm). All lights that
are through TeO2 crystal in whole field of view (FOV angle is 5 degree) forms an imagines onto the staring focal plane
array by Bragg diffraction. The diffraction wavelength of AOTF can be adjusted by the radio frequency signal. The
three-dimensional data cube is composed of two-dimension of object space and wavelength in this way, and the graph
and spectral are synthesized and implemented. The AOTF hyperspectral imaging spectrometer operating in visible/near
infrared waveband is analyzed, and the detailed analysis data is also presented. The AOTF hyperspectral imaging test is
studied and developed, and the analysis of data and the next developing advice is given. We also analyze the method
about selection of material and technological design in middle wave/long wave infrared waveband of AOTF
hyperspectral imaging system.
The paper outlines a simulation system based on the IR liquid crystal light valve (LCLV) and describes the design of the
optical systems for simulator including the variable magnification lens and the projection optics. The simulator is used in
testing of an infrared imaging system, which has two field angles of 6° and 8°. The variable magnification lens between
the LCD panel and the LCLV produce a visible image at varying magnifications on the LCLV. The projection optics
collimates the infrared image which is inverted by the LCLV to generate an infrared scene in the 8~12μm waveband. The
varying image size meets the need of the test IR imaging system, which field angle varies. The projection optics is
designed for a constant field angle and constant entrance pupil. Thus the IR image always fills the entrance aperture and
FOV of the test optical system. A long working distance and sufficient exit pupil distance of the projection optical
system ensure the mechanical and the optical assembly, and match the simulator exit pupil to the imagery system
entrance pupil. The Modulation Transfer Function (MTF) and spot diagram show the perfect image quality of the
This document describes the simulation principle, outlines the design procedure of the projection optics system from predesign to achromatization. The Optical system collimates output from Liquid crystal light valve in 8~12μm and enables an imaging system to be tested out of 20°field of view. The effective focal length of this F/1.5 system is about 113mm. There is sufficient exit pupil distance to match projector exit pupil to the LWIR imagery system entrance pupil. A long working distance between Liquid crystal light valve and the optics system is approximately 120mm. The Modulation Transfer Function (MTF) and the geometric blur spot for three-field position repenting an on-axis point, a full field and an intermediate point show the better performance of the optical system.