Research Issues in Using Reconfigurable Computing to Accelerate Infrared Simulation

We describe the development of a 3-D statistically nonstationary earthlimb stochastic structure representation and its application to earthlimb infrared (IR) background structure simulations. An earthlimb viewing geometry is defined by the location of both observer and source in space. The line-of-sight tangent altitude is the minimum altitude of the trajectory, defined at the earth-centered perpendicular to the line of sight. The stochastic structure overlay is constructed from a 2-D diagonal cut through a 3-D matrix of correlated Gaussian deviates; each plane of the matrix represents a statistically constant representation of the 2-D correlation lengths at a given altitude above the earth. Each matrix plane is generated using successive 2-D fast Fourier transform routines that have empirical values of vertical and horizontal correlation lengths as input. The total deviate variance versus altitude is then scaled from empirical measurements of fluctuations in atmospheric density, temperature, and/or emissivity. These structure generators are used both as perturbations on input atmospheric data to IR radiance codes and as high-resolution overlays to earthlimb lR mean-radiance 2-D scenes. An IR structured scene realization and scene validation analysis is presented.

The importance of hard-ware-in-the-loop infrared seekers testing with realistic infrared scenes warrants a review of the current technologies used in dynamic infrared scene simulation. Infrared seeker dynamic scene simulation technology includes dynamic infrared simulator technology and infrared scene image generation technology. Infrared simulator includes resistor arrays, liquid crystal light valves, laser writers, laser diode arrays, CRT and digital mirror devices (DMD). The technology that may provide high performance for testing seekers is the DMD approach. Other technologies such as resistor arrays, LCLVs, laser diodes, and the CRTs are still under development. Infrared scene generation can be divided into the stage of data generation and the stage of programming. Target 3D model is completed by the software of Multigen Creator and dynamic scene image generation is completed by the software of Vega. The SensorVision module of Vega can supply the atmosphere model parameter and target texture material.

Dynamic infrared scene simulation using grayscale modulation of digital micro-mirror device

An automatic selection method and its application to key search algorithms

Adaptive grid-based confidence assessment for synthetic optoelectronic images by Physical Reasonable Infrared Scene Simulation Engine (PRISSE)

The aim of the work described in this paper, is to generate realistic infra-red (IR) images of sea clutter including sun glint, suitable for the testing of image analysis and detection algorithms. The accuracy of detection algorithms can only be determined by using a wide variety of test data representing different scene parameters such as sea state, sun angles and camera position. This type of data is extremely costly and difficult to obtain in practical trials. Synthetic generation of such scenes offers the capability to generate suitable data sets at a fraction of the cost, whilst offering precise control over the scene parameters. A model suitable for the generation of such data is developed and some results of synthetic IR scenes are presented. The model presented in this paper consists of three parts, namely: 1. The generation of the sea surface, including: animation of the wave motion. 2. The computer graphics required for the viewing of the scene. 3. The computation of the IR radiance for each element of the scene.

A few years ago, a microlithographic deposition process on infrared-transmitting substrates was developed in order to produce realistic infrared scenes for FLIR testing. In recent months, the performance of this product, named Thermoscene, has been improved by improving the control over the production process. The two main results are: (1) An increase in the number of simulated grey levels from 15 to 290, without reduction of the total number of pixels. (2) A decrease in imperfections, such as unwanted holes in the mesh deposition, to almost zero. The Thermoscene is useful as a component of infrared simulators, to project realistic infrared scenes through collimating optics to a FLIR, missile seeker, etc., for testing purposes.

An approach to utilize the symmetric multiprocessing environment of the Silicon GraphicsTM (SGI) OnyxTM and Onyx2TM has been developed to support the generation of infrared (IR) scenes in real-time. This development, supported by the Navy, is driven by a desire to maximize use of commercial-off-the-shelf (COTS) hardware and minimize cost and development time. In the past, real-time IR scene generators have been developed as custom architectures that are expensive and difficult to maintain. An SGI based Real- time Infrared Scene Simulator (RISS) system was developed to utilize the SGI's fast symmetric multiprocessing hardware to perform real-time IR scene radiance calculations for scene objects. During real-time scene simulation, the SGI symmetric multiprocessors are used to update polygon vertex locations and compute radiometrically accurate floating point radiance values. The output of this process can be utilized to drive a variety of scene rendering engines including the SGI Reality Engine2TM, the SGI Infinite RealityTM, and Amherst Systems' custom Scene Rendering System. This paper will discuss the critical technologies that apply to infrared scene generation and hardware-in-the- loop testing using COTS hardware. Specifically, the application of RISS high-fidelity real time radiance algorithms on the SGI's symmetric multiprocessing hardware will be discussed. Also, issues relating to the integration of the real-time algorithms with various rendering engines and external real-time control will be addressed.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The digital micromirror device DMD is widely used in visible light projection, special-purpose spatial light modulation, and infrared scene simulation, due to its high resolution, uniformity and energy concentration. In some applications that require high frame rate scene image display, it is necessary to ensure that the DMD displays high gray level images at a high frame rate. However, the display frame rate of the pulse width modulation (PWM) method is limited by the minimum time required for DMD loading data, unable to achieve high frame rate display. Although the DMD binary display mode can meet the requirements of high frame rate display, it cannot meet the requirements of high gray level. The paper proposes an image display method that uses light source and DMD to synchronize modulation. Decompose the high-order gray image into bit planes according to the gray threshold, and the DMD displays each bit plane in binary mode under the trigger of an sync pulse. The intensity of the illumination laser source is modulated by an acousto-optic modulator to match the bit plane and the radiated laser power. This method makes use of the function of high frame rate display in DMD binary mode cooperate with light intensity modulation of illumination laser source, and realizes high frame rate and high dynamic range image display. With this method, the maximum frame rate of 8-bit gray level image with 1920 ×1080 resolution can reach 2KHz. The experimental system has realized 200Hz frame rate display of 8-bit gray level image with 1920 ×1080 resolution.

OPTRA is developing a two-band midwave infrared scene simulator based on digital micromirror devices (DMD). The simulator is intended for testing a number of different infrared tracking technologies. Our approach allows for the relative intensities of the two spectral bands to be varied for realistic simulations of an approaching target. The system employs a broadband IR (thermal) source whose energy is spectrally filtered via a series of bandpass filters acting as dichroic beamsplitters prior to being imaged onto two DMDs - one for each spectral band. The "on" reflected images from the two DMDs are then fused, expanded by a telescope, and transmitted towards the unit under test. The relative intensities of each spatial element of the two bands are controlled through the duty cycle of "on" versus "off" of the related micromirror. In this paper we present a breadboard design, build, and test which establishes the feasibility of our approach. A description of the opto-mechanical system is given along with radiometric performance projections. Results from breadboard testing, including maximum radiant intensity and radiant intensity resolution, and a series of simulated images are shown.

Reliable modeling for thermal infrared (IR) signatures of real-world city scenes is required for signature management of civil and military platforms. Traditional modeling methods generally assume that scene objects are individual entities during the physical processes occurring in infrared range. However, in reality, the physical scene involves convective and conductive interactions between objects as well as the radiations interactions between objects. A method based on radiosity model describes these complex effects. It has been developed to enable an accurate simulation for the radiance distribution of the city scenes. Firstly, the physical processes affecting the IR characteristic of city scenes were described. Secondly, heat balance equations were formed on the basis of combining the atmospheric conditions, shadow maps and the geometry of scene. Finally, finite difference method was used to calculate the kinetic temperature of object surface. A radiosity model was introduced to describe the scattering effect of radiation between surface elements in the scene. By the synthesis of objects radiance distribution in infrared range, we could obtain the IR characteristic of scene. Real infrared images and model predictions were shown and compared. The results demonstrate that this method can realistically simulate the IR characteristic of city scenes. It effectively displays the infrared shadow effects and the radiation interactions between objects in city scenes.

Rapid standoff spectroscopic characterization of plastic waste using quartz tuning fork

Large IR detector arrays, particularly ones intended for military and aerospace applications, are often difficult and expensive to directly test. These detectors require an IR projector for scene simulation. Current methods for testing such sensors rely heavily on expensive field test programs and/or utilize lower performance thermal emission-based IR scene projectors. Recently there has been increased interest and development of seminconductor-based infrared (IR) LED-based emitter array devices (e.g. SLEDS), due to their ability to produce higher apparent temperatures, lower background temperatures, and much faster rise and fall times than thermal emission techniques. These devices flip-chip a large CMOS driver chip onto a two-dimensional array of IR emitter devices typically fabricated on a GaSb substrate. Several testing sessions showed the unique functionality and capabilities in several important areas such as: apparent temperature exceeding 1000 Kelvin, rise and fall time of 3–4 microseconds, and low apparent background temperatures. Unfortunately, SLEDS arrays require the removal of kW-level heat fluxes while being maintained at liquid-nitrogen temperatures. Although multiple project for construction of these IR emitter arrays are underway, currently there appears to be no cooling system available to operate these arrays at the performance level that they are capable of achieving.

In this study, a novel IR projector driver that can minimize nonuniformity in electric circuits, using a dual-current-programming structure, is proposed to generate high-quality infrared (IR) scenes for accurate sensor evaluation. Unlike the conventional current-mode structure, the proposed system reduces pixel-to-pixel nonuniformity by assigning two roles (data sampling and current driving) to a single transistor. A prototype of the proposed circuit was designed and fabricated using the SK-Hynix 0.18 µm CMOS process, and its performance was analyzed using post-layout simulation data. It was verified that nonuniformity, which is defined as the standard deviation divided by the mean radiance, could be reduced from 21% to less than 0.1%.

Effective coordination and synchronization between processes remains a challenge that becomes even more important with the rise of multicore hardware. This thesis introduces Octopus, a coordination service for the Barrelfish operating system. Octopus addresses the problem of coordination between concurrent processes or activities in Barrelfish. The Octopus design is influenced by ideas from distributed computing. We show that these ideas are transferrable to operating systems. We used a declarative, logic programming engine to implement parts of the Octopus service and evaluate the benefits and drawbacks of this approach. In a case study, we used Octopus to write a service that is responsible for device management and bootstrapping the OS as well as a replacement for the Barrelfish name server. Our experience with Octopus has shown that it simplifies programming services that require complex coordination patterns by a great deal, while at the same time offering a flexible API for a programmer to solve a wide range of coordination and synchronization problems.