一种飞机目标及典型地物红外辐射仿真方法

机场场景内的飞机目标及其所处的地物背景具有重要军事应用价值,为了实现对这类目标的检测、识别以及动态监测,需要一套能够在不同季节、不同气象条件、不同时段、不同探测波段等条件下机场场景内飞机/地物红外辐射仿真的软件来提供训练样本。在Visual Studio 2010环境下,利用OpenGL构建了典型机场场景下飞机及地物背景模型,结合传热学和红外辐射理论的分析,将一款用于热红外分析的RadThermIR软件内核嵌入算法中,提出一种计算飞机及其地物背景的红外辐射场模型和构建其红外图像仿真方法。以图像灰度相似度作为评价指标,该方法和真实红外图像相比,仿真精度高于80%,实验结果表明,该方法可为实现全天候机场场景下飞机目标自动检测识别提供丰富的红外特性分析数据和特性知识训练样本。     

基于多旋翼无人机的热红外地表温度场反演系统设计

对当前城市热岛效应研究所采用的三类主要方法进行了分析,分别得出其优势和存在的不足,提出了一种基于微小型多旋翼无人机平台开发小尺度高分辨率地表温度场观测系统的创新思路,并通过对红外测温原理的研究,设计了热红外无人机地表温度场反演系统,开发了B/S架构的地表温度场反演软件,实现了红外图像实时传输、自动拼图、米级网格化地表温度场反演、实景地图叠加、历史数据回放和数据导出等功能。经多次飞行实践应用表明,该系统运行稳定、数据准确、投资少,机动灵活,使用方便,可弥补传统卫星遥感等观测手段的不足,为开展城市区域热环境精细化观测提供了一种新的技术平台与工具,也为气象无人机的应用开辟了一个新的方向。     

基于毫米波辐射特性的水面植被检测方法

针对采用3 mm波段辐射计对水面植被辐射特性进行检测的问题,在研究分析了水面的亮度温度和水面植被的介电特性的基础上,采用相干法建立了水面植被辐射特性的多层介质模型,与3层介质模型相比,仿真结果与实验数据更加吻合,表明多层介质模型能更精确地模拟水面植被的辐射特性;通过实验得出,在不同的入射角下,水面植被亮温相比水面亮温均有上升,说明水面相比植被具有亮温低、冷目标的毫米波辐射特征,可利用毫米波辐射特性监测区域内水面植被。     

一种有效计算大气红外辐射传输效应的方法

红外辐射在大气中的传输特性对红外成像仿真研究具有重要意义.本文以红外辐射的传输理论为基础,综合考虑大气分子的吸收、散射,气象条件以及海拔高度等因素,提出了一种以大气条件为基本参数,计算红外成像仿真中大气光谱透过率的方法,并对算法进行了仿真实现;通过对不同条件下计算结果的分析,表明用该算法得出的结论与实际红外成像的规律基本相符,且可以满足实时性和准确性的要求,能够增强红外成像仿真的可信度,具有很好的应用价值.     

动态场景红外图像的压缩感知域高斯混合背景建模

针对动态场景下红外图像的背景模型构建问题,提出一种基于压缩感知（Compressed sensing,CS）域高斯混合模型（Gaussian mixture model,GMM）的背景建模方法.该方法不是对图像中的每个像素建立高斯混合模型,而是对图像局部区域的压缩感知测量值建立高斯混合模型.1）通过提取红外图像轮廓的角点特征,估计相邻帧图像间的相对运动参数以对图像进行校正与配准;2）将每帧图像网格化为适当数目的局部子图,利用序列图像构建每个局部子图的压缩感知域高斯混合背景模型;3）采用子空间学习训练稀疏字典,通过子空间追踪对可能含有目标的局部子图进行选择性稀疏重构;4）通过背景减除实现前景目标检测.以红外图像数据集CDnet2014和VIVID PETS2005进行实验验证,结果表明：该方法能建立有效的动态场景红外图像背景模型,对成像过程中所受到的场景动态变化、背景扰动等具有较强的鲁棒性,其召回率、精确率、F-measure等性能指标及处理速度较之于同类算法具有明显优势.     

高炉温度场的红外图像识别检测方法及应用

针对高炉炉内温度场的分布及高炉布料的情况,提出了一种基于红外图像处理的高炉温度场检测方法。它通过红外图像处理来建立温度场分布模型,结合十字测温进行温度定标,实现了高炉温度场分布在线监视,为指导高炉布料提供了一种有效的途径。基于图像处理的温度检测技术具有非接触、低成本、易维护、实时性的特点,使其在冶金、建材、热电厂等场合有着广泛的应用前景。     

红外图像的自适应混合消噪方法

针对带有高斯噪声和脉冲噪声的红外图像,提出一种自适应混合去噪方法。首先将受脉冲噪声和高斯噪声污染的像素区分开来,然后对被脉冲噪声污染的像素采用自适应层叠中值滤波法,对被高斯噪声污染的像素采用基于局部噪声方差估计的自适应局部滤波法。实验表明,该方法在信噪比(SNR)和最小均方误差(MSE)的改善上明显优于线性平滑滤波法和普通中值滤波算法,并具有较好的图像细节保护能力和较快的滤波速度。     

基于神经网络的混合模型建模方法及应用

神经网络凭借其对非线性的处理能力被广泛应用于实际系统的黑箱建模,但在理论上可以任意逼近模型的神经网络在实际应用中的能力是有限的,对于复杂动态特性的实际系统基于神经网络的模型在逼近效果和泛化能力上都存在不足.提出了基于神经网络的混合模型建模方法,建立的模型由通过传统方法建立的基本系统和由神经网络建立的逼近实际系统和基本模型之间差值的不确定部分组成,用此方法建模大大提高了模型的精度和对不同输入的泛化能力,通过对多个系统的建模仿真结果验证其可行性.     

压电振动能量采集器的力电耦合模型及其功率优化*

为提高传统压电振动能量采集器集总参数模型的性能预测精度,考虑悬臂梁的振型信息与轴向应变分布情况,提出了一种改进的力电耦合模型,该模型引入无因次幅值修正因子,通过曲线拟合方法确定了修正因子与振型函数和振动幅值之间的关系表达式;利用Rayleigh-Ritz模态分析法确定了力电耦合模型中的集总等效参数(如质量、刚度等),并根据弹性动力学原理建立了能量采集器的运动控制方程,得到了稳态时能量采集器的力、电输出响应表达式;最后,利用改进的模型对能量采集器的负载电阻和输出功率进行了优化,得到了负载短路和负载开路时能量采集器的最优输出特性。仿真结果与实例对比验证了提出模型的正确性,表明改进的力电耦合模型具有较高的预测精度。     

基于子空间辨识的煤气混合加压过程建模方法

本文针对高炉煤气与焦炉煤气混合加压过程,提出一种基于子空间辨识的过程状态与输出关系建模方法.通过分析过程的强耦合特性,以蝶阀前的高炉煤气压力和流量、焦炉煤气压力和流量为过程状态,混合煤气热值和压力为输出,采用子空间辨识方法建立了一个4输入2输出的关系模型.仿真实验表明,建立的模型有效地反映了过程特性,具有较高的辨识精度.     

基于本体的仿真系统元概念模型研究*

在仿真系统的概念模型开发过程中存在着模型重用性不高和缺乏管理等问题,这些问题将影响模型开发效率和仿真系统的可靠性.为解决以上问题,提出了元概念模型(MCM)的概念,以实现在更高层次对概念模型进行抽象.将本体思想引入MCM的设计中,提出了基于本体的元概念模型(OMCM)建模方法,并给出了OMCM的层次结构和建模方法.最后,将该方法应用于装备保障仿真系统元概念模型的建模中,得到了较好的验证.     

Characterising groundwater use by vegetation using a surface energy balance model and satellite observations of land surface temperature

This study presents a novel ‘model-data’ approach to detect groundwater-dependent vegetation (GDV), through differences in modelled and observed land surface temperatures (LST) in space and time. Vegetation groundwater use is inferred where modelled LST exceeds observed LST by more than a threshold determined from consideration of systematic and random errors in model and observations. Modelled LST was derived from a surface energy balance model and LST observations were obtained from Terra-MODIS thermal imagery. The model-data approach, applied in the Condamine River Catchment, Queensland, Australia, identified GDV coincident to existing mapping. GDV were found to use groundwater up to 48% of the time and for as many as 56 consecutive days. Under driest of conditions, groundwater was estimated to contribute up to 0.2 mm h⁻¹ to total ET for GDV. The ability to both detect the location and water-use dynamics of GDV is a significant advancement on previous remote-sensing GDV methods.     

基于标准差的地形三维表面模型建立方法*

针对二维数据域的Delaunay三角剖分推广到空间时存在的关键问题,提出一种基于标准差的地形三维表面模型建立算法.与空外接圆准则相比,该算法在计算时考虑了附加高程信息,引入标准差作为构网判断准则.剖析了标准差的含义,为什么使用标准差以及基于标准差的剖分准则,最后给出基于标准差的地形三维表面模型建立算法的具体步骤,并通过一个具体实例对算法进行了验证.     

A detection problem: Sensitivity and uncertainty analysis of a land surface temperature approach to detecting dynamics of water use by groundwater-dependent vegetation

Sustainable management of groundwater-dependent vegetation (GDV) requires the accurate identification of GDVs, characterisation of their water use dynamics and an understanding of associated errors. This paper presents sensitivity and uncertainty analyses of one GDV mapping method which uses temperature differences between time-series of modelled and observed land surface temperature (LST) to detect groundwater use by vegetation in a subtropical woodland. Uncertainty in modelled LST was quantified using the Jacobian method with error variances obtained from literature. Groundwater use was inferred where modelled and observed LST were significantly different using a Student's t-test. Modelled LST was most sensitive to low-range wind speeds (<1.5 m s⁻¹), low-range vegetation height (<=0.5 m), and low-range leaf area index (<=0.5 m² m⁻²), limiting the detectability of groundwater use by vegetation under such conditions. The model-data approach was well-suited to detection of GDV because model-data errors were lowest for climatic conditions conducive to groundwater use.     

基于专家评估和信息融合的高炉料面温度场智能建模

高炉料面温度分布对于高炉操作有着重要的指导意义.本文针对高炉目前无法准确全面了解料面温度分布的情况,挖掘现场已有数据,依据可信度理论,建立红外图像可信度评估的专家规则;根据评估结果,分别采用依靠红外图像的机理模型信息融合方法和不依靠红外图像的神经网络信息融合方法,建立基于专家评估和多源信息的高炉料面温度场模型.在某钢铁企业2 200 m3高炉应用结果表明,该模型可以更为准确,直观地反映料面温度分布,实现了对料面温度分布的实时检测,为复杂冶金过程控制和监控提供了有效的解决方法.     

Evaluation of ASTER and MODIS land surface temperature and emissivity products using long-term surface longwave radiation observations at SURFRAD sites

Land surface temperature (LST) and emissivity are key parameters in estimating the land surface radiation budget, a major controlling factor of global climate and environmental change. In this study, Terra Advanced Spaceborne Thermal Emission Reflection Radiometer (ASTER) and Aqua MODerate resolution Imaging Spectroradiometer (MODIS) Collection 5 LST and emissivity products are evaluated using long-term ground-based longwave radiation observations collected at six Surface Radiation Budget Network (SURFRAD) sites from 2000 to 2007. LSTs at a spatial resolution of 90 m from 197 ASTER images during 2000-2007 are directly compared to ground observations at the six SURFRAD sites. For nighttime data, ASTER LST has an average bias of 0.1 °C and the average bias is 0.3 °C during daytime. Aqua MODIS LST at 1 km resolution during nighttime retrieved from a split-window algorithm is evaluated from 2002 to 2007. MODIS LST has an average bias of − 0.2 °C. LST heterogeneity (defined as the Standard Deviation, STD, of ASTER LSTs in 1 × 1 km² region, 11 × 11 pixel in total) and instrument calibration error of pyrgeometer are key factors impacting the ASTER and MODIS LST evaluation using ground-based radiation measurements. The heterogeneity of nighttime ASTER LST is 1.2 °C, which accounts for 71% of the STD of the comparison, while the heterogeneity of the daytime LST is 2.4 °C, which accounts for 60% of the STD. Collection 5 broadband emissivity is 0.01 larger than that of MODIS Collection 4 products and ASTER emissivity. It is essential to filter out the abnormal low values of ASTER daily emissivity data in summer time before its application.     

In situ angular measurements of thermal infrared sea surface emissivity—Validation of models

In this paper, sea surface emissivity (SSE) measurements obtained from thermal infrared radiance data are presented. These measurements were carried out from a fixed oilrig under open sea conditions in the Mediterranean Sea during the WInd and Salinity Experiment 2000 (WISE 2000). The SSE retrieval methodology uses quasi-simultaneous measurements of the radiance coming from the sea surface and the downwelling sky radiance, in addition to the sea surface temperature (SST). The radiometric data were acquired by a CIMEL ELECTRONIQUE CE 312 radiometer, with four channels placed in the 8-14 μm region. The sea temperature was measured with high-precision thermal probes located on oceanographic buoys, which is not exactly equal to the required SST. A study of the skin effect during the radiometric measurements used in this work showed that a constant bulk-skin temperature difference of 0.05±0.06 K was present for wind speeds larger than 5 m/s. Our study is limited to these conditions. Thus, SST used as a reference for SSE retrieval was obtained as the temperature measured by the contact thermometers placed on the buoys at 20-cm depth minus this bulk-skin temperature difference.SSE was obtained under several observation angles and surface wind speed conditions, allowing us to study both the angular and the sea surface roughness dependence. Our results were compared with SSE models, showing the validity of the model of Masuda et al. [Masuda, K., Takashima, T., & Takayama, Y. (1988) Emissivity of pure seawaters for the model sea surface in the infrared window regions. Remote Sensing of Environment, 24, 313-329.] for observation angles up to 50°. For larger angles, the effect of double or multiple reflections on the sea surface produces discrepancies between measured and theoretical SSEs, and more complex models should be used to get accurate SSE values, such as the model of Wu and Smith [Wu, X., & Smith, W.L. (1997). Emissivity of rough sea surface for 8-13 μm: modelling and verification. Applied Optics, 36, 2609-2619.].     

Modelling daytime thermal infrared directional anisotropy over Toulouse city centre

Measurements of thermal infrared (TIR) directional anisotropy (difference between off-nadir and nadir brightness temperatures) performed over the city of Toulouse using a method based on the use of 2 airborne TIR cameras are presented. Results from 3 flights at different times during a summer day (July 15th 2004) and from 1 flight in winter (February 25th 2005) all confirm important anisotropy (up to 10 °C) and hot spot effects as previously reported in literature. A simple simulation approach is then proposed. It is based on the aggregation in any viewing direction of 6 directional temperatures (sunlit/shaded walls/streets/roofs) weighted by their corresponding surface ratios within the scene viewed. The city is described by 18 canyon streets oriented in all directions by 10° steps and the 6 temperatures are determined by integrating simulations of the energy balance model SOLENE repeated for the 18 canyon streets. The surface ratios are computed from images of the studied area generated with the POV-Ray software (Persistence of Vison Raytracer, http://www.povray.org/). This method is described in detail. The modelled anisotropy compares favourably with the measurements on all dates, despite a systematic underestimation ranging between 15 and 30%. The possible sources of discrepancy including sensitivity to the aspect ratio and to the surface parameters and possible impact of microscale structures are briefly discussed and several improvements of the modelling system are suggested.     

线性扫描浮法玻璃温度监控系统中误差分析

介绍红外线性扫描浮法玻璃退火窑玻璃温度场在线监控系统,提出浮法玻璃红外测温技术所引入的影响测温精度的因素,并对退火窑玻璃带测温精度影响因素及误差进行综合分析。