This PDF file contains the front matter associated with SPIE Proceedings Volume 8707, including the Title Page, Copyright information, Table of Contents, Introduction, and the Conference Committee listing.

A model is described for the problem of optimally projecting a pixellated light source onto a pixellated imaging sensor, in the context that the projected source is used for performance testing of the sensor. The model can be used, for example, to compute the paraxial design requirements of the projection lens, given that the parameters of all other subsystems in the problem are fixed. For remote sensing applications, where the performance of a sensor focused at infinity is to be tested, the projector lens becomes a collimator. For optimal projection when using the source for performance testing of the sensor, one then requires that the projector pixels are not spatially resolved by the imaging sensor, the entrance pupil of the sensor is overfilled without vignetting, and also, where feasible, the sensor field of view is overfilled. The model uses paraxial analytical ray tracing approximations to provide a set of equations that are used in an associated spreadsheet to determine the basic collimator requirements such as effective focal length, f/#, and relief distance, given the geometrical characteristics of the projector spatial light modulator and the sensor under test. Beyond this, the model provides a sense of intuition and guidance prior to detailed computerized ray tracing.

We report on the design and testing of a 2-color dynamic scene projector system based on the MIRAGE-XL infrared scene projector. The system is based on the optical combination of two 1024x1024 MIRAGE-XL resistive arrays. Algorithms derived for 2-color operation are discussed and system performance data is presented, including radiometric performance, sub-pixel spatial co-registration and compensation for spectral cross-talk.

Recently, the US Army developed a prototype shortwave infrared (SWIR) multispectral polarized scene projector (MPSP) system. This system is capable of projecting single spectral images as well as videos with full polarization content from 850 to 1650 nm with variable spectral bandwidth. The bandwidth can vary between 12 and 100 nm. A multistage liquid crystal tunable filter is used to tune the wavelength of light with desired bandwidth and three reflective 512x512 liquid crystal on silicon (LCoS) spatial light modulators (SLMs) with 37.5 μm pixel pitch are used to project an image with all Stokes parameters. This scene projector is intended to characterize hardware-in-the loop spectral and polarization performance of spectropolarimetric imagers operating in the SWIR region. We used this projector to characterize a SWIR hyperspectral imager with a single polarization based on an acousto-optic tunable filter (AOTF). Here, we will briefly describe the scene projector and the hyperspectral imager, discuss the experimental setup and present the results of our characterization.

OPTRA is developing a next-generation digital micromirror device (DMD) based two-band infrared scene projector (IRSP) with infinite bit-depth independent of frame rate and an order of magnitude improvement in contrast over the state of the art. Traditionally DMD-based IRSPs have offered larger format and superior uniformity and pixel operability relative to resistive and diode arrays, however, they have been limited in contrast and also by the inherent bitdepth / frame rate tradeoff imposed by pulse width modulation (PWM). OPTRA’s high dynamic range IRSP (HIDRA SP) has broken this dependency with a dynamic structured illumination solution. The HIDRA SP uses a source conditioning DMD to impose the structured illumination on two projector DMDs – one for each spectral band. The source conditioning DMD is operated in binary mode, and the relay optics which form the structured illumination act as a low pass spatial filter. The structured illumination is therefore spatially grayscaled and more importantly is analog with no PWM. In addition, the structured illumination concentrates energy where bright object will be projected and extinguishes energy in dark regions; the result is a significant improvement in contrast. The projector DMDs are operated with 8-bit PWM, however the total projected image is analog with no bit-depth / frame rate dependency. In this paper we describe our progress towards the development, build, and test of a prototype HIDRA SP.

The Missile Defense Transfer Radiometer (MDXR) is designed to calibrate infrared collimated and flood sources over the fW/cm² to W/cm² power range from 3 μm to 28μ m in wavelength. The MDXR operates in three different modes: as a filter radiometer, a Fourier-transform spectrometer (FTS)-based spectroradiometer, and as an absolute cryogenic radiometer (ACR). Since 2010, the MDXR has made measurements of the collimated infrared irradiance at the output port of seven different infrared test chambers at several facilities. We present a selection of results from these calibration efforts compared to signal predictions from the respective chamber models for the three different MDXR calibration modes. We also compare the results to previous measurements made of the same chambers with a legacy transfer radiometer, the NIST BXR. In general, the results are found to agree within their combined uncertainties, with the MDXR having 30 % lower uncertainty and greater spectral coverage.

There is a need for a Precision Radiometric Surface Temperature (PRST) measurement capability that can achieve noncontact profiling of a sample’s surface temperature when heated dynamically during laser processing, aerothermal heating or metal cutting/machining. Target surface temperature maps within and near the heated spot provide critical quantitative diagnostic data for laser-target coupling effectiveness and laser damage assessment. In the case of metal cutting, this type of measurement provides information on plastic deformation in the primary shear zone where the cutting tool is in contact with the workpiece. The challenge in these cases is to measure the temperature of a target while its surface’s temperature and emissivity are changing rapidly and with incomplete knowledge of how the emissivity and surface texture (scattering) changes with temperature. Bodkin Design and Engineering, LLC (BDandE), with partners Spectral Sciences, Inc. (SSI) and Space Computer Corporation (SCC), has developed a PRST Sensor that is based on a hyperspectral MWIR imager spanning the wavelength range 2-5 μm and providing a hyperspectral datacube of 20-24 wavelengths at 60 Hz frame rate or faster. This imager is integrated with software and algorithms to extract surface temperature from radiometric measurements over the range from ambient to 2000K with a precision of 20K, even without a priori knowledge of the target’s emissivity and even as the target emissivity may be changing with time and temperature. In this paper, we will present a description of the PRST system as well as laser heating test results which show the PRST system mapping target surface temperatures in the range 600-2600K on a variety of materials.

Ground testing of space- and air-borne imaging sensor systems is supported by Vis-to-LWIR imaging sensor calibration and characterization, as well as hardware-in-the-loop (HWIL) simulation with high-fidelity complex scene projection to validate sensor mission performance. To accomplish this successfully, there must be the development of tools, technologies, and methodologies that are used in space simulation chambers for such testing. This paper provides an overview of such efforts being investigated and implemented at Arnold Engineering Development Complex (AEDC).

At DSTO, a real-time scene generation framework, VIRSuite, has been developed in recent years, within which trials data are predominantly used for modelling the radiometric properties of the simulated objects. Since in many cases the data are insufficient, a physics-based simulator capable of predicting the infrared signatures of objects and their backgrounds has been developed as a new VIRSuite module. It includes transient heat conduction within the materials, and boundary conditions that take into account the heat fluxes due to solar radiation, wind convection and radiative transfer. In this paper, an overview is presented, covering both the steady-state and transient performance.

Rendering of point scatterer based radar scenes for millimeter wave (mmW) seeker tests in real-time hardware-in-the-loop (HWIL) scene generation requires efficient algorithms and vector-friendly computer architectures for complex signal synthesis. New processor technology from Intel implements an extended 256-bit vector SIMD instruction set (AVX, AVX2) in a multi-core CPU design providing peak execution rates of hundreds of GigaFLOPS (GFLOPS) on one chip. Real world mmW scene generation code can approach peak SIMD execution rates only after careful algorithm and source code design. An effective software design will maintain high computing intensity emphasizing register-to-register SIMD arithmetic operations over data movement between CPU caches or off-chip memories. Engineers at the U.S. Army Aviation and Missile Research, Development and Engineering Center (AMRDEC) applied two basic parallel coding methods to assess new 256-bit SIMD multi-core architectures for mmW scene generation in HWIL. These include use of POSIX threads built on vector library functions and more portable, highlevel parallel code based on compiler technology (e.g. OpenMP pragmas and SIMD autovectorization). Since CPU technology is rapidly advancing toward high processor core counts and TeraFLOPS peak SIMD execution rates, it is imperative that coding methods be identified which produce efficient and maintainable parallel code. This paper describes the algorithms used in point scatterer target model rendering, the parallelization of those algorithms, and the execution performance achieved on an AVX multi-core machine using the two basic parallel coding methods. The paper concludes with estimates for scale-up performance on upcoming multi-core technology.

The performance parameters influence the design of a Flight Motion Simulator (FMS) and affect its dynamic accuracies. A highly dynamic simulator needs low inertias and lightweight gimbals. This is counterproductive for a system with high position accuracies. A simulator with high position accuracy requires a stiff, rigid system with minimal deflections. Critical parameters that affect the FMS design are payload sizes, accuracies, and dynamic requirements.