ADS 80数码航摄仪L0级影像后处理试验

介绍了三线阵数码航摄仪ADS 80,探讨了其Level 0级影像的后处理技术,分析了不同软件在相同地面分辨率下不同地面控制条件下的后处理精度。得出的结论是控制点分布、数量、位置和航摄影像地面分辨率对ADS 80相机L0级影像空三解算和生成的L1级影像精度影响较大;在充分考虑以上因素的情况下,ADS 80相机在获取的航摄影像地面分辨率低于成图比例尺要求时仍能得到较高的校正精度。     

DEM matching for bias compensation of rigorous pushbroom sensor models

DEM matching is a technique to match two surfaces or two DEMs, at different reference frames. It was originally proposed to replace the need of ground control points for absolute orientation of perspective images. This paper examines DEM matching for precise mapping of pushbroom images without ground control points. We proved that DEM matching based on 3D similarity transformation can be used when model errors are only on the platform’s position and attitude biases. We also proposed how to estimate bias errors and how to update rigorous pushbroom sensor models from DEM matching results. We used a SPOT-5 stereo pair at ground sampling distance of 2.5 m and a reference DEM dataset at grid spacing of 30 m and showed that rigorous pushbroom models with accuracy better than twice of the ground sampling distance both in image and object space have been achieved through DEM matching. We showed further that DEM matching based on 3D similarity transformation may not work for pushbroom images with drift or drift rate errors. We discussed the effects of DEM outliers on DEM matching and automated removal of outliers. The major contribution of this paper is that we validate DEM matching, theoretically and experimentally, for estimating position and attitude biases and for establishing rigorous sensor models for pushbroom images.     

Remote sensing techniques to locate ground water potential zones in upper Urmil River Basin, district Chhatarpur — Central India

In the present study efforts have been made to locate favourable zones for ground water targeting using IRS-USS-II data, Hydromorphogeological lineament, lineament density and ground water prospect maps have been prepared through visual interpretation of geocoded images on 1:50,000 scale and Survey of India topographical maps of the same scale. The resulting base line information has been integrated for evaluating ground water potential of mapping units. The alluvial plain, flood plain, infilled valley and deeply buried pediplain ace the prospective zones of ground water exploration and development. Fractures and faults parallel to drainage courses constitute priority zones for ground water targetting.     

PHOTOGRAPHIC SURVEYING OF FLAT COUNTRY

Abstract

THE mapping of flat country from the ground always entails much more work than the mapping of hilly country for the obvious reason that the nearness of the horizon, coupled with the obstruction of trees, buildings, and vegetation, restricts the view, and long lines are not possible. In contrast to this, mapping from air-photographs becomes much more simple when the country is flat, for the photographic projection is not complicated by height distortions, and it is only necessary to correct for distortions caused by the impossibility of keeping the camera perfectly horizontal at the instant of exposure. During the past four years in Bengal and the United Provinces, where the alluvial plains scarcely vary a foot from monotonous flatness, many thousands of square miles have been surveyed photographically, and excellent maps have been made on a scale of 16 inches to 1 mile and are being used by Settlement Officers for purposes of land assessment.     

Testing satellite and ground thermal imaging of low-temperature fumarolic fields: The dormant Nisyros Volcano (Greece)

The Nisyros Volcano (Greece) was monitored by satellite and ground thermal imaging during the period 2000–2002. Three night-scheduled Landsat-7 ETM⁺ thermal (band 6) images of Nisyros Island were processed to obtain land surface temperature. Ground temperature data were also collected during one of the satellite overpasses. Processed results involving orthorectification and 3-D atmospheric correction clearly show the existence of a thermal anomaly inside the Nisyros Caldera. This anomaly is associated mainly with the largest hydrothermal craters and has land surface temperatures 5–10 °C warmer than its surroundings. The ground temperature generally increased by about 4 °C inside the main crater over the period 2000–2002. Ground thermal images of the hydrothermal Stephanos Crater were also collected in 2002 using a portable thermal infrared camera. These images were calibrated to ground temperature data and orthorectified. A difference of about 0–2 °C was observed between the ground thermal images and the ground temperature data. The overall study demonstrates that satellite remote sensing of low-temperature fumarolic fields within calderas can provide a reliable long-term monitoring tool of dormant volcanoes that have the potential to reactivate. Similarly, a portable thermo-imager can easily be deployed for real-time monitoring using telemetric data transfer. The operational costs for both systems are relatively low for an early warning system.     

二维控制场建立中的关键技术研究

本文对控制点标志的选择进行分析,指出选择的基本原则;提出了基于像点与物方之间几何关系来识别点的方法。阐述了对目标影像的分割、定位及光束法平差解算物方点的空间坐标,并根据验后方差确定观测值的权;给出了一个二维控制场建立的实例,物方控制点的坐标中误差小于±0.2mm。     

EVALUATION OF METRIC CAMERA PHOTOGRAPHY FOR MAPPING AND CO-ORDINATE DETERMINATION

Rigorous photogrammetric methods have been used to carry out a detailed evaluation of Metric Camera panchromatic photographs of two areas, one in south-east France and the other on the coast of Libya. Inner, relative and absolute orientation and space resection were performed in order to determine how accurately ground co-ordinates can be obtained and the most suitable scale for mapping. Results of absolute orientation (residuals of 19m in plan and 26m in height) indicate that it is possible to produce maps at 1:100000 scale with contours at 100m intervals. Plotting has been done at 1:100000 scale showing cultural and drainage features. It was not possible to identify all detail which is plotted on existing 1:100000 scale line maps.     

资源三号国产星敏感器事后定姿方案设计与系统实现

作为绝对姿态测量精度最高的仪器,星敏感器已广泛应用在当前大多遥感卫星上,其定姿精度直接影响光学测绘遥感卫星的几何定位能力。针对资源三号卫星首次下传的国产APS原始星图数据,设计并实现了一套基于国产星图的地面事后定姿方案。该方案充分利用地面事后定姿时间充足、计算资源丰富的特点,重点对星图预处理、星表重构、星图识别、恒星相机在轨检校等关键技术进行优化和改进,实现了一套资源三号国产星敏感器事后定姿系统,并将其应用于基于国产星图的绝对姿态确定中。利用资源三号卫星下传原始星图对该系统进行全面试验验证,结果分析表明,事后定姿系统不仅可靠性高,而且定姿精度达到1.82角秒（1σ,光轴指向精度）,优于星上处理2.18 角秒（1σ）,为资源三号卫星原始星图业务化处理提供了技术保障。     

POS辅助机载LiDAR无地面控制点DEM,DOM制作

DEM和DOM已成为航空遥感生产的重要产品,机载Li DAR系统获取的具有三维坐标信息的点云数据,经系统误差校正和滤波分类后,结合机载POS数据和数码影像,可进行无地面控制点的DEM和DOM制作。经实践分析,成果精度满足1∶2 000比例尺DEM和1∶5 000比例尺DOM精度指标,该方法产品制作周期短,成果质量较高,满足了无人区和应急情况下的测绘需求。     

Soil image segmentation and texture analysis: a computer vision approach

Automated processing of digitized soilsection images reveals elements of soil structure and draws primary estimates of bioecological importance, like ground fertility and changes in terrestrial ecosystems. We examine a sophisticated integration of some modern methods from computer vision for image feature extraction, texture analysis, and segmentation into homogeneous regions, relevant to soil micromorphology. First, we propose the use of a morphological partial differential equation-based segmentation scheme based on seeded region-growing and level curve evolution with speed depending on image contrast. Second, we analyze surface texture information by modeling image variations as local modulation components and using multifrequency filtering and instantaneous nonlinear energy-tracking operators to estimate spatial modulation energy. By separately exploiting contrast and texture information, through multiscale image smoothing, we propose a joint image segmentation method for further interpretation of soil images and feature measurements. Our experimental results in images digitized under different specifications and scales demonstrate the efficacy of our proposed computational methods for soil structure analysis. We also briefly demonstrate their applicability to remote sensing images.     

遥测地表温度与比辐射率的迭代反演方法──理论推导与数值模拟

首先在地表比辐射率为已知的条件下,提出一个非线性迭代温度反演模型,我们对不同的地表和大气条件进行了模拟计算,结果表明当大气温度廓线误差－２Ｋ－２Ｋ,水汽廓线误差±２０％时的温度均方根误差为０．４８Ｋ。当大气模式误差一个模式时反演的温度均方根误差为０．８５Ｋ。在此基础上,引人相邻像元的概念,相邻像元的大气状况可以认为是相同的,应用两个时相的遥感影像数据,假定在两个相近时相之间地表比辐射率值不变,建立地表比辐射率与温度的反演模型。我们对不同的地表和大气条件进行了模拟计算,结果表明当大气温度廓线误差－２Ｋ－２Ｋ,水汽廓线误差±２０％时地表温度均方根误差小于１．５Ｋ,地表比辐射率均方根误差小于０．０２,地表辐射均方根误差为１％;当大气温度廓线误差－２Ｋ－２Ｋ,水汽廓线误差±１０％时,地表温度均方根误差小于１．０Ｋ,地表辐射均方根误差小于０．６％。     

天绘一号03星三线阵/多光谱载荷影像质量评价

2015年10月26号发射的天绘一号03星是中国传输型立体测绘卫星天绘一号系列的第3颗卫星。三线阵和多光谱影像数据是天绘一号卫星的重要数据,用于立体测绘、彩色融合、遥感观测等多种用途。因此,为了推动天绘一号03卫星影像数据早日为相关领域提供服务,本文采用客观评价的方法,对天绘一号03星的三线阵和多光谱影像质量进行了全面的评价分析。评价结果显示(天绘一号)03星的清晰度、对比度、细节能量、边缘能量、功率谱、信息容量指标值远高于天绘一号01、02星。说明天绘一号03星三线阵/多光谱影像在地物细节和边缘纹理特征的描述上优于天绘一号01、02星,同时载荷接收的信息量远高于天绘一号01、02星。天绘一号03星较高的信噪比指标说明其载荷抑制噪声的能力优于天绘一号01、02星。边缘辐射畸变和增益调整畸变表明在辐射均匀程度上,天绘一号03星三线阵/多光谱影像介于天绘一号01和02星之间。因此,与同类天绘一号01,02星的三线阵与多光谱影像相比,天绘一号03星影像质量有着显著的提高。     

空间实验室图像的制图能力分析及其地学应用——以西藏日喀则地区和珠峰地区的试验为例

本文论述了空间实验室测量相机(MC)拍摄的彩色红外立体像对在中比例尺地形制图、正射影像地图以及土地资源调查中的应用可能性,给出1:10万和1:20万比例尺的制图例证,表明平面位置和高程精度能满足1:10万比例尺地形图规范要求;1:10万比例尺影像图可以满足专题制图精度要求。 应用数字图像处理技术,将二种来源(MC,MSS)的遥感数据做数字匹配,并进行信息提取、组合、增强和分类等处理,其结果与原始图像比较表明有独特的优越性,与MSS原始数据相比,图像的空间分辨率明显提高,各种类型界线更分明,可分辨类目增多;而与MC原始图像相比,其光谱特性获得改善且能保持原有的空间分辨率。土地利用类型解释精度与MSS和MC原始图像比较分别提高7—20％左右。     

Comparison of reconnaissance soil maps prepared by conventional method and landsat imagery interpretation

Landsat images have been used in conjunction with topographical and geological information to prepare soil map of Mudhol taluk in Bijapur district, Karnataka state. The map has been compared with the reconnaisance map prepared by conventional method using 1:63,360 scale Survey of India toposheets. The study reveals that more accurate soil maps in terms of boundary delineation and composition of soil mapping units could be prepared by interpretation of Landsat images with adequate ground data. The method can thus be used in revising and improving many of the existing reconnaissance soil maps prepared by conventional method.     

结合特征分量构建和面向对象方法提取高分辨率卫星影像阴影

针对高分辨率卫星影像,提出一种特征分量构建与面向对象结合的阴影提取方法。分析遥感阴影光谱特性,构建彩色不变特征C3、亮度特征I、主成分第一特征量PC1以及蓝色波段和近红外波段归一化比率特征RATIOb_nir,增强阴影信息。采用线性变换将几个特征分量Digital Number(DN)值归一化到相同范围,对这几个分量进行综合分析。以I和PC1分量为输入对影像进行多尺度分割,建立包括波段均值、标准差、最大差异等特征的规则集,实现面向对象的阴影信息提取。选取20幅QuickBird影像为例进行阴影提取实验,平均总体精度为97%,平均用户精度为96%,平均Kappa系数为0.94。实验结果表明,相对传统基于像素信息提取方法,本文方法提取阴影斑块完整,无破碎图斑;相对基于原始光谱的面向对象方法,本文方法提取精度更高。     

基于有理多项式模型的星载高分InSAR影像制作数字高程模型的研究

合成孔径雷达干涉测量是一种利用SAR影像复数据的相位信息提取地面三维信息的技术,它通过获取地面目标在两幅SAR影像上的相位差值来解算该点的三维坐标。有理多项式（RPC,Rational Polynomial Coefficient）模型作为一种数学意义上的几何模型,它独立于传感器和平台,简单且具有通用性,可建立地面任意坐标与影像空间的关系。本文在RPC模型用于替代星载SAR的距离多普勒模型和星载InSAR的干涉相位方程基础上,研究 RPC模型应用于星载高分辨率InSAR影像制作DEM的可行性和精度。利用兰州COSMO-SkyMed数据和资源三号三线阵数据制作的DEM为参考数据进行实验验证,RPC模型用于InSAR技术生成的DEM,中误差为7.55米。     

The use of motor-glider in topoclimatic studies

This paper reports on the advantages and disadvantages of motor-glider use in studying topoclimates. Despite the widespread use of images taken from low-altitude flying platforms (planes, helicopters, UAVs), the use of a motor-glider for imagery collection has not been reported in environmental studies. In presented study, the low-altitude remote sensing techniques were used to increase the spatial resolution of thermal maps derived from Landsat ETM+ thermal bands. Thermal images from motor-glider were taken by a thermovision camera. At the local scale, land surface temperature (LST) is one of the factors influencing topoclimatic diversity hence, by analysing LST distribution one can determine topoclimatic variability. Topoclimate has been the subject of previous studies, however, they have not used thermal remote sensing in the research process but instead relied on ground measurement network. The presented research contributes to better understanding of the thermal environment of the Earth by employing an innovative data collection method suitable for relatively large areas under specific weather conditions. The data collection with motor glider offers good spatial resolution of less than 1 m and facilitates the compilation of good quality LST maps. The paper discusses the influence of spatial resolution on LST variability and demonstrates gain in information granularity resulting from sub-meter resolution of collected data.     

Age discrimination among eruptives of Menengai Caldera,Kenya, using vegetation parameters from satellite imagery

This paper reports an investigation to determine the degree to which digitally processed Landsat TM imagery can be used to discriminate among vegetated lava flows of different ages in the Menengai Caldera, Kenya. Since Landsat data display vegetation parameters well, and plant communities vary with type and depth of soil development, selective digital processing techniques were applied to take advantage of these characteristics for discriminating relative age differences of the underlying volcanics. A selective series of five images, consisting of a color‐coded Landsat 5 classification and four color composites, were compared with geologic maps. These included a color coded, modified, unsupervised classification and contrast enhanced, color composite images using TM bands 3–2–1, 4–3–2 and 7–5–3, and the first 3 Karhunen‐Loeve transformation axes that had been generated using 7 Landsat TM bands.

The most recent of more than 70 post‐caldera flows within the caldera are trachytes, which are variably covered by shrubs and subsidiary grasses. Soil development evolves as a function of time, and as such, supports a changing plant community. Progressively older flows exhibit the increasing dominance of grasses over bushes. It was found that the Landsat images correlated well with geologic maps, but that the two mapped age classes could be further subdivided on the basis of different vegetation communities. It is concluded that field maps can be modified, and in some cases corrected by use of such imagery, and that digitally enhanced Landsat imagery can be a useful aid to field mapping in similar terrains.     

Land subsidence prediction in Beijing based on PS-InSAR technique and improved Grey-Markov model

Land subsidence induced by excessive groundwater withdrawal has caused serious social, geological, and environmental problems in Beijing. Rapid increases in population and economic development have aggravated the situation. Monitoring and prediction of ground settlement is important to mitigate these hazards. In this study, we combined persistent-scatterer interferometric synthetic aperture radar with Grey system theory to monitor and predict land subsidence in the Beijing plain. Land subsidence during 2003–2014 was determined based on 39 ENVISAT advanced synthetic aperture radar (ASAR) images and 27 RadarSat-2 images. Results were consistent with global positioning system, leveling measurements at the point level and TerraSAR-X subsidence maps at the regional level. The average deformation rate in the line-of-sight was from ?124 to 7 mm/year. To predict future subsidence, the time-series deformation was used to build a prediction model based on an improved Grey-Markov model (IGMM), which adapted the conventional GM(1,1) model by utilizing rolling mechanism and integrating a k-means clustering method in Markov-chain state interval partitioning. Evaluation of the IGMM at both point level and regional scale showed good accuracy (root-mean-square error <3 mm; R² = 0.94 and 0.91). Finally, land subsidence in 2015–2016 was predicted, and the maximum cumulative deformation will reach 1717 mm by the end of 2016. The promising results indicate that this method can be used as an alternative to the conventional numerical and empirical models for short-term prediction when there is lack of detailed geological or hydraulic information.     

Visual discrimination of surface features of salt affected soils using satellite images in arid region of Rajasthan (India)

The study has been carried for visual discrimination of natural salt affected soils on FCC images of IRS 1 B in Pali district of Rajasthan. The salt affected soils show wide variations in salinity (EC_2.53.7 to 28 dSm^-1), alkalinity (pH 8.5-9.8), cover ofP. juliflora (10-90%), salt tolerant grasses (10–55%) and gravelly surface (20–35%). ThoughP. juliflora and grasses were present at most of the observation points their cover decreased with soil EC_2.5 values more than 10 and 13 dSm^-1, respectively. Five darkness categories derived as the result of visual interpretation of FCCs; and ground and laboratory studies revealed that the darkness category 1 represented fewer plant community with high salinity (EC 28.7 dSm^-1) and gravelly surface, categories 2 and 3 were characterised by grass cover and moderate salt affected soils (EC 3-10 dSm^-1) whereas category 4 was dominated by thicket ofP. juliflora. The derived numerical darkness categories of the FCC images were slightly low for February images. The darkness values of observation pixel on February images correlated positively withP. juliflora cover and negatively with grass cover and soil pH indicating that surface features on FCC were related with the immediate observation pixels.