Real-Time Generation of Dynamic Infrared Scene

Although many models have been put forward to realize static infrared scene, they could not generate dynamic infrared scene real time in interactive way. In this paper a new method is proposed to solve the problem. We first model the targets and background of infrared scene based on the hybrid way of geometry and multi-spectral texture images. Then considering the attenuation effect of atmosphere and the noise mechanic of infrared image sensor, we present an infrared depth image model to generate dynamic images of the objects in the scene from different viewpoint. The complexity of infrared dynamic scene is thus reduced greatly and the reality of infrared scene is improved. Finally, real-time walkthrough for infrared scene is successfully realized and the average walkthrough speed is larger than 25 frames per second.     

Generation of Dynamic Infrared Outer Space Scene

This paper proposes a new method to generate the dynamic infrared outer space scene in real time. In the paper, we first model the dynamic infrared background of star sky based on the infrared star catalogue and temporal and spacial coordinate transformations. We also present a new concept called infrared star magnitude for given infrared receiving wavebands to display the infrared star sky effectively. Then we put forward an infrared image synthesis model for outer space targets based on the method of divided elements and energy equilibrium. To generate the dynamic infrared outer space scene, several simplification and accelerating techniques such as Billboard, Levels of Details and Occlusion Culling are hired to accelerate the generating speed of the scene. Finally infrared images of targets, background of outer space scene at different infrared receiving wavebands are drawn and the dynamic infrared outer space scene is successfully carried out in real time. * Corresponding author     

Infrared optical modulators for missile testing

The continued proliferation of imaging infrared (I²R) missile systems has created the need for fully representative infrared scene generators. In order to test these I²R systems correctly a very large dynamic range is required of the scene generator. This cannot easily be produced by the standard approach of an array of suspended resistor heater elements. This paper therefore describes the fabrication of infrared optical modulators for use in high dynamic range and high frame rate scene generation. Modulation is produced by the heating of a variable reflectivity coating. This is achieved by coating a suitable substrate with a thin film of vanadium dioxide (VO₂) via a reactive sputtering process. VO₂ undergoes a semiconductor to metal phase transition at approximately 68°C and the associated change in reflectivity is exploited to create the modulator. The correct stoichiometry of the thin film of VO₂ is critical in producing high frame rate devices. Both transmissive and reflective modulators are described.     

High dynamic range compression and detail enhancement of infrared images in the gradient domain

To find the trade-off between providing an accurate perception of the global scene and improving the visibility of details without excessively distorting radiometric infrared information, a novel gradient-domain-based visualization method for high dynamic range infrared images is proposed in this study. The proposed method adopts an energy function which includes a data constraint term and a gradient constraint term. In the data constraint term, the classical histogram projection method is used to perform the initial dynamic range compression to obtain the desired pixel values and preserve the global contrast. In the gradient constraint term, the moment matching method is adopted to obtain the normalized image; then a gradient gain factor function is designed to adjust the magnitudes of the normalized image gradients and obtain the desired gradient field. Lastly, the low dynamic range image is solved from the proposed energy function. The final image is obtained by linearly mapping the low dynamic range image to the 8-bit display range. The effectiveness and robustness of the proposed method are analyzed using the infrared images obtained from different operating conditions. Compared with other well-established methods, our method shows a significant performance in terms of dynamic range compression, while enhancing the details and avoiding the common artifacts, such as halo, gradient reversal, hazy or saturation.     

Research on DMD infrared scene projector with a high contrast ratio infrared prism design

In this paper a single-DMD infrared scene projector with a high contrast ratio prism design of the illumination optical system is presented. By using the innovative infrared three-element TIR prism group, the off-state and flat-state light that reflected by the DMD could be all steered away from the projection lens. The contrast ratio and optical efficiency has been improved with this three-element TIR prism as the light-separator. This DMD infrared scene projector also features low-profile and compact structure. The illumination and projection optical systems are proved to be of great efficient light utilization. In this letter we analyze the impacts of optical efficiency on temperature simulation. This architecture with three-element TIR prism added could be used in IRSP based single-DMD to improve contrast and optical efficiency.     

Infrared Image Simulation Based On Statistical Learning Theory

A real-time simulation algorithm of infrared image based on statistical learning theory is presented. The method includes three contents to achieve real-time simulation of infrared image, such as acquiring the training sample, forecasting the scene temperature field value by statistical learning machine, data processing and data analysis of temperature field. The simulation result shows this algorithm based on ν - support vector regression have better maneuverability and generalization than the other method, and the simulation precision and real-time quality are satisfying.     

发动机热喷流红外辐射计算与仿真

利用求每个小视场视线方向辐射亮度的方法计算喷流红外辐射的光谱分布。以辐射传递方程数值和形式为基础,采用Malkmus统计窄谱带模型和Curtis-Godson(CG)近似求视线方向的辐射强度。采用CFD分析软件FLUENT模拟流场和组分摩尔分数分布。建立喷流红外成像仿真模型,仿真生成了液体火箭发动机热喷流红外图像。结果表明,该方法可以很好地分辨出流场的细微结构。该模型也适用于航空发动机喷流红外辐射计算与仿真。     

法庭科学领域中微量物证的显微红外技术鉴定

在法庭科学领域中,由于案件现场提取到的物证通常是极微量的,另外样品形态各异、成分复杂,常规红外光谱分析技术常常无法达到检测要求。显微红外技术是基于傅里叶变换红外光谱技术与显微镜技术的结合发展起来的。与常规红外光谱技术相比,显微红外技术具有检测灵敏度高、微区分析和无损检测等优点,测试时几乎不引入外部干扰,卓有成效地解决了法庭科学领域中微量物证鉴定的难题,可以满足微量物证必须保留以用于法庭作证的特殊需要。通过本实验中心测试的真实案例分析,详细阐述了显微红外技术在法庭科学领域中微量物证鉴定方面的优势。采用显微红外技术,本文分别对油漆物证、塑料物证、橡胶物证、纤维物证、药物和毒物物证进行了红外光谱振动特征的比对分析,为各类刑事案件和交通肇事案件的定性提供有力的谱学依据。实验结果表明,显微红外技术具有常规红外测试技术无法比拟的优势,是法庭科学领域中微量物证鉴定的有效手段。     

Salient contour extraction from complex natural scene in night vision image

The theory of center-surround interaction in non-classical receptive field can be applied in night vision information processing. In this work, an optimized compound receptive field modulation method is proposed to extract salient contour from complex natural scene in low-light-level (LLL) and infrared images. The kernel idea is that multi-feature analysis can recognize the inhomogeneity in modulatory coverage more accurately and that center and surround with the grouping structure satisfying Gestalt rule deserves high connection-probability. Computationally, a multi-feature contrast weighted inhibition model is presented to suppress background and lower mutual inhibition among contour elements; a fuzzy connection facilitation model is proposed to achieve the enhancement of contour response, the connection of discontinuous contour and the further elimination of randomly distributed noise and texture; a multi-scale iterative attention method is designed to accomplish dynamic modulation process and extract contours of targets in multi-size. This work provides a series of biologically motivated computational visual models with high-performance for contour detection from cluttered scene in night vision images.     

红外景象模拟器的测试方法探讨

红外景象模拟器是检验红外制导系统性能的半实物仿真试验系统的关键设备,其性能关系到半实物仿真试验的可信度。介绍了一种对各种不同类型的红外景象模拟器的动、静态辐射特性进行测试的通用方法,通过理论分析得出了红外景象模拟器的一些基本性能参数,这些工作将对红外景象模拟器的研制和改进具有一定的指导意义。     

安全距离和成像尺寸约束的超大视场红外系统车载应用关键参数论证

在现有车载辅助驾驶系统中,可见光成像系统难以有效应用于夜晚、雨、雾、霾等低照度不良天气。红外成像系统有效克服了上述不足,但传统车载红外系统存在视场角小、视野盲区大的缺点。研究了超大视场红外系统的车载辅助驾驶应用,提出了基于安全距离和成像尺寸联合约束的超大视场红外系统关键参数论证方法。通过分析等距投影成像规律,建立了超大视场红外系统车载应用的安全距离约束模型和成像尺寸约束模型,以极限速度对应的探测最近距离和二维Johnson准则约束下的“发现”最远距离来验证超大视场红外车载系统的可行性,计算了视场角等关键参数。经过理论论证和分析,超大视场红外车载系统的镜头焦距/像元尺寸范围需在[276.1 521.3]范围之内。通过开展系统试验,设计了水平视场角为140°的超大视场红外成像系统,满足了对人的发现距离大于130 m的要求,进而可用于车辆辅助驾驶。     

虚拟情景实训环境三维模拟

应用计算机技术当中的虚拟模拟技术,对于当前各领域实现虚拟情景三维模拟训练已成为可能。本文研究当前技术环境下,利用Unity3D模拟平台构造虚拟情景训练系统的开发与设计。从三维模拟训练系统的关键技术研究入手,以三维场景优化、物理碰撞逻辑检测、动态加载场景以及网络通信作为开发的重点,设计出较为先进和逼真的虚拟情境下三维模拟训练系统。并以消防部门作为系统应用的检测部门,检测结果表示此系统可以很好的表现出现场场景的模拟程度以及逻辑,对于加强消防部门的训练技术和应用效果有很大优势。     

Improvement in adaptive nonuniformity correction method with nonlinear model for infrared focal plane arrays

The scene adaptive nonuniformity correction (NUC) technique is commonly used to decrease the fixed pattern noise (FPN) in infrared focal plane arrays (IRFPA). However, the correction precision of existing scene adaptive NUC methods is reduced by the nonlinear response of IRFPA detectors seriously. In this paper, an improved scene adaptive NUC method that employs “S”-curve model to approximate the detector response is presented. The performance of the proposed method is tested with real infrared video sequence, and the experimental results validate that our method can promote the correction precision considerably.     

On the proposal of quantitative temperature measurement by using three-color technique combined with several infrared sensors having different detection wavelength bands

We developed the previous infrared sensing technique, the two-color technique, to establish further a more general technique to measure the temperature quantitatively under near-ambient conditions. The quantitative temperature measurement, three-color technique, was newly proposed by combining three kinds of infrared radiometers having different detection wavelength bands. The measurement can also be done by adding three infrared filters to one infrared radiometer. The radiometers have a selective detection wavelength band of several μm in width which is in the range of 2–13 μm. The method was confirmed using numerical simulation to allow a parametric study of how the result varies for different values of emissivity corresponding to the respective infrared radiometers. An experimental investigation was also performed to evaluate the measurement error and the adaptability of the technique. As this technique has a feature that can perform quantitative temperature measurement for objective surfaces at each picture element without presuming any emissivity, reflectivity and ambient conditions, there is a possibility that the technique will be useful for various medical or engineering disciplines.     

Raman Spectra of Porphyrins

The spectroscopy of porphyrins has been developing rapidly during the last two decades, this class of compounds being of great biological importance and possessing a number of significant properties. Different spectroscopic techniques, viz., electronic spectroscopy including fine-structure quasiline spectra (Shpolsky effect), infrared spectroscopy, luminescence, flash photolysis, ESR and NMR spectroscopy etc., have been applied to the study of these molecules (see reference ¹ for a review). However until recently there were no publications on Raman spectra of porphyrins and related compounds although it is evident that a complete analysis of molecular vibrations is impossible without knowing the Raman frequencies, especially for centrosymmetrical molecules. We have obtained Raman spectra of two porphin derivatives, viz., copper and nickel octamethylporphin ² which seems to be, together with data on hemoglobin and cytochrome^3-5 and on chlorophylls ⁶, the first observation of Raman spectra of porphyrins. In this paper Raman spectra of several metalloporphyrins are presented including metal complexes of porphin, octamethylporphin, etioporphyrin I, meso-tetraphenylporphin and tetrabenzporphin. For some of them Shpolsky spectra have been obtained and a juxtaposition is made of the two kinds of spectral data concerning the frequencies of molecular no- modss. Also some data of infrared spectra are presented.     

On the generation and maintenance of waves and turbulence in simulations of free-surface turbulence

One of the challenges in numerical simulation of wave–turbulence interaction is the precise setup and maintenance of wave and turbulence fields. In this paper, we investigate techniques for the generation and suppression of specific surface wave modes, the generation of turbulence in an inhomogeneous physical domain with a wavy boundary-fitted grid, and the generation and maintenance of waves and turbulence during the complex wave–turbulence interaction process. We apply surface pressure to generate and suppress waves. Based on the solution of linearized Cauchy–Poisson problem, we derive three pressure expressions, which lead to a δ-function method, a time-segment method, and a gradual method. Numerical experiments show that these methods generate waves as specified and eliminate spurious waves effectively. The nonlinear wave effect is accounted for with a time-relaxation method. For turbulence generation, we extend the linear forcing method to an inhomogeneous physical domain with a curvilinear computational grid. Effects of force distribution and computational grid distortion are examined. For wave–turbulence interaction, we develop an algorithm to instantaneously identify specific progressive and standing waves. To precisely control the wave amplitude in a complex turbulent flow field, we further develop an energy controlling method. Finally, a simulation example of wave–turbulence interaction is presented. Results show that turbulence has unique features in the presence of waves. Velocity fluctuations are found to be strongly dependent on the wave phase; variations of these fluctuations are explained by the pressure–strain correlation associated with the wave-induced strain field.     

Single infrared image super-resolution combining non-local means with kernel regression

In many infrared imaging systems, the focal plane array is not sufficient dense to adequately sample the scene with the desired field of view. Therefore, there are not enough high frequency details in the infrared image generally. Super-resolution (SR) technology can be used to increase the resolution of low-resolution (LR) infrared image. In this paper, a novel super-resolution algorithm is proposed based on non-local means (NLM) and steering kernel regression (SKR). Based on that there are a large number of similar patches within an infrared image, NLM method can abstract the non-local similarity information and then the value of high-resolution (HR) pixel can be estimated. SKR method is derived based on the local smoothness of the natural images. In this paper the SKR is used to give the regularization term which can restrict the image noise and protect image edges. The estimated SR image is obtained by minimizing a cost function. In the experiments the proposed algorithm is compared with state-of-the-art algorithms. The comparison results show that the proposed method is robust to the noise and it can restore higher quality image both in quantitative term and visual effect.     

Performance of the infrared microspectroscopy station at SSRF

At the third generation synchrotron light source Shanghai Synchrotron Radiation Facility (SSRF), the first infrared beamline BL01B has been successfully constructed. The infrared beamline collects both bending magnet and edge radiation. A brief introduction of the infrared beamline design has been given in this article. The infrared microspectroscopy station is equipped with a Nicolet 6700 FTIR spectrometer and a Nicolet Continuum Microscope. The flux at the entrance of the FTIR spectrometer, the intensity profile, the signal to noise ratio (SNR) with different apertures, and the focused spot size of the infrared microspectroscopy station have been measured. The performances with synchrotron radiation infrared source and internal globar source have been compared. The results indicate that the infrared microspectroscopy station at SSRF has the ability of analysis samples in a small area with diffraction limited spatial resolution.     

Generation of Realistic Infrared Image for Moving Objects

Most of current methods are available for synthesizing the static infrared scene, but fail to simulate the infrared signature of the objects caused by motion. This paper presents a new method for generating realistic infrared image of moving objects. Considering various environmental factors, object geometry and structure, internal heat conditions and state of movement, an infrared image synthesis model for moving objects is established. Based on this model the rendering method for infrared image of this kind of objects is proposed. By incorporating the effect of atmosphere transmission and the noise mechanism of infrared sensor, the infrared images of the working aircraft and automobile are successfully generated from different viewpoint. Experimental results illustrate the potential of our method.