SPOT6卫星图像处理关键技术研究

从正射纠正、图像融合及波段选择与组合等关键技术入手,对2012年9月获取的SPOT6卫星图像进行处理,初步研究结果表明:在正射纠正中,在辅助信息相同且精度较高的前提下,利用有理函数模型(rational function model,RFM)和严格物理模型(rigorous physical model,RPM)纠正的图像均能达到1∶1.5万比例尺正射影像图的制图精度,但RPM方法的纠正精度明显优于RFM的,且对地面控制点数量需求上,RPM最少需要8个,而RFM仅需要3~4个;在图像融合中,Pan Sharp变换法融合的图像在信息量、光谱特征和边缘特征等方面具有综合优势;在波段选择及组合中,若以信息提取为目的,认为B4(R)B1(G)[(B2+B3)/2](B)波段组合最优,若以制图为目的,选择B3(R)B2(G)B1(B)波段组合效果更佳。     

Measuring rural settlement expansion in Uzbekistan using remote sensing to support spatial planning

Population growth demands sustainable spatial planning strategies for settlements in Uzbekistan, Central Asia, especially in rural areas that are inhabited by approximately 64 percent of the country's population. Where can settlements expand in rural Uzbekistan and does settlement growth affect valuable agricultural land? SPOT-5 data with a resolution of 2.5 m was utilized for mapping building layers and assessing settlement growth between 2006 and 2011 at the example of 53 communities located in the Khorezm province in North-West Uzbekistan. Object based image analysis was conducted, i.e. a multi-scale segmentation for the derivation of building contours, followed by a random forest (RF) classification of the object's spectral and spatial characteristics. A geographical information system (GIS) was used for identifying settlement densification and expansion processes, and for quantifying agricultural land parcels of different soil quality occupied during settlement growth.A calibration routine based on indices of segmentation quality enabled the selection of optimal segmentation parameters. After GIS-based refinements of the RF classification results, the overall accuracy (OA) of the building layers of both years exceeded 95%. The OA of the change map was 92.7%. The results revealed that the building area increased by 20%, whilst settlement expansion amounted to 10% in 2006–2011. Settlements widely expanded in accordance with the existing rules prohibiting the conversion of agricultural land to housing areas. Nevertheless, about 20% of the settlement growth occurred on agricultural production areas, also on those with highly productive soils. The results indicated both, the pressure on land resources for settlement growth and – in face of continuous population growth – an increasing demand for comprehensive spatial planning in rural Uzbekistan. The elaborated methodological approach can be extrapolated to regions throughout Central Asia with similar environmental conditions.     

Extracting vegetation phenology metrics in Changbai Mountains using an improved logistic model

Remotely sensing images are now available for monitoring vegetation dynamics over large areas.In this paper,an improved logistic model that combines double logistic model and global function was developed.Using this model with SPOT/NDVI data,three key vegetation phenology metrics,the start of growing season (SOS),the end of growing season (EOS) and the length of growing season (LOS),were extracted and mapped in the Changbai Mountains,and the relationship between the key phenology metrics and elevation were ...     

Semi-supervised support vector regression model for remote sensing water quality retrieving

This paper proposed a semi-supervised regression model with co-training algorithm based on support vector machine, which was used for retrieving water quality variables from SPOT5 remote sensing data. The model consisted of two support vector regressors (SVRs). Nonlinear relationship between water quality variables and SPOT5 spectrum was described by the two SVRs, and semi-supervised co-training algorithm for the SVRs was established. The model was used for retrieving concentrations of four representative pollution indicators—permanganate index (CODmn), ammonia nitrogen (NH₃-N), chemical oxygen demand (COD) and dissolved oxygen (DO) of the Weihe River in Shaanxi Province, China. The spatial distribution map for those variables over a part of the Weihe River was also produced. SVR can be used to implement any nonlinear mapping readily, and semi-supervised learning can make use of both labeled and unlabeled samples. By integrating the two SVRs and using semi-supervised learning, we provide an operational method when paired samples are limited. The results show that it is much better than the multiple statistical regression method, and can provide the whole water pollution conditions for management fast and can be extended to hyperspectral remote sensing applications.     

基于SPOT影像的筏式养殖区提取方法研究

本文以山东省荣成市黑泥湾及其北部海域作为研究区,分析了筏式养殖区在SPOT5假彩色合成影像上的亮度特征;根据纯水体亮度受悬沙分布影响较大的特点,设计了以邻域分析为基础的图像增强及分类方法,并在ArcGIS软件中实现;运用Erdas软件聚类统计、去除分析工具消除噪声,提高精度。该方法可快速监测浅海筏式养殖区空间分布情况,为提高用海管理水平并进行科学用海规划提供服务。     

辽宁太子河上游沿岸景观格局的幅度效应

河岸景观幅度效应是河流生态学研究的关键问题,是河岸管理的重要依据.基于2008年2.5m的SPOT5影像解译的景观类型图,应用缓冲带分析和景观格局指数分析,研究了辽宁太子河上游河流沿岸25 m、50 m、100m、200 m、500 m和1000m范围的景观幅度效应.结果表明:①河流两侧景观具有明显的幅度效应.距河道近的区域表现出具有多种景观要素的密集格局,斑块类型呈均衡化分布趋势,破碎化程度和丰富度较高;随距河道距离的增加,区域具有优势景观类型,景观中斑块形状变的规则,均匀度和丰富度降低.②景观类型分布具有区域性.草地和裸地主要分布在河道两侧50～100 m内,农田和居民地主要分布在河道两侧100～200 m内;离河道越远的区域受人类干扰越小,林灌植被保存好;研究区内河滩总面积较小,多分布在距河流25～50 m范围.③河流两侧景观在类型尺度和景观尺度上均具有明显的幅度效应,但由于景观自身发育和人类活动的异质性,幅度效应在不同类型间表现不同.     

海岸带地区SPOT卫星影像大气校正方法比较及精度验证

为获得反演海岸带地区地表真实反射率的最佳大气校正方法,分别利用DOS、6S及FLAASH三种模型对SPOT卫星影像进行大气校正,对比分析校正前后影像的典型地物光谱曲线及NDVI指数的变化情况,并对结果进行精度验证。研究表明:三种大气校正模型均能有效去除大气对遥感影像的影响,获取较为准确的地表反射率信息;对比河流、水库、海水、植被、城镇、裸地等六种典型地物校正前后的光谱曲线,与DOS及6S模型相比,FLAASH模型校正结果中各地物反射率差别较大、特征明显,能较好的还原地表真实情况;NDVI指数检验显示,FLAASH模型对地物NDVI响应更强烈,在地物光谱响应特征分析等方面具有更强的优势,是三种模型中最适宜海岸带地区SPOT影像的大气反演方法。研究方法及结论可为同类研究提供参考与借鉴。     

Interpretation of landslide distribution triggered by the 2005 Northern Pakistan earthquake using SPOT 5 imagery

The 2005 northern Pakistan earthquake (magnitude 7.6) of 8 October 2005 occurred in the northwestern part of the Himalayas. We interpreted landslides triggered by the earthquake using black-and-white 2.5-m-resolution System Pour l’Observation de la Terre 5 (SPOT 5) stereo images. As a result, the counts of 2,424 landslides were identified in the study area of 55 by 51 km. About 79% or 1,925 of the landslides were small (less than 0.5 ha in area), whereas 207 of the landslides (about 9%) were large (1 ha and more in area). Judging from our field survey, most of the small landslides are shallow rock falls and slides. However, the resolution and whitish image in the photos prevented interpreting the movement type and geomorphologic features of the landslide sites in detail. It is known that this earthquake took place along preexisting active reverse faults. The landslide distribution was mapped and superimposed on the crustal deformation detected by the environmental satellite/synthetic aperture radar (SAR) data, active faults map, geological map, and shuttle radar topography mission data. The landslide distribution showed the following characteristics: (1) Most of the landslides occurred on the hanging-wall side of the Balakot–Garhi fault; (2) greater than one third of the landslides occurred within 1 km from the active fault; (3) the greatest number of landslides (1,147 counts), landslide density (3.2 counts/km²), and landslide area ratio (2.3 ha/km²) was found within Miocene sandstone and siltstone, Precambrian schist and quartzite, and Eocene and Paleocene limestone and shale, respectively; (4) there was a slight trend that large landslides occurred on vertically convex slopes rather than on concave slopes; furthermore, large landslides occurred on steeper (30° and more) slopes than on gentler slopes; (5) many large landslides occurred on slopes facing S and SW directions, which is consistent with SAR-detected horizontal dominant direction of crustal deformation on the hanging wall.     

SPOT 5 HRS立体影像无(稀少)控制绝对定位技术研究

研究了SPOT5卫星HRS立体影像的成像原理，构建了无需地面控制点的直接对地绝对定位模型。实验表明，无控制绝对定位结果存在不同程度的系统误差；利用任意位置的1个地面控制点消除系统误差后即可获得较好的平面和高程定位精度；利用1个地面控制点外推580km进行绝对定位时，平面定位精度仍优于20m，高程定位精度约10m，说明卫星轨道本身具有较好的稳定性，显示了本模型具有良好的应用前景。     

SPOT卫星影像居民地信息自动提取的决策树方法研究

以南京市江宁县为研究区域，首先分析了该区域居民地的影像特征，然后研究了居民地及其背景地物在SPOT—4(Ⅺ)卫星影像4个波段上的光谱特征，并由此探讨了它们在光谱特征上的可分性。研究发现，除道路在光谱特征上与居民地差异不大而难以完全分开外，其它背影地物均可以依据各波段亮度值的大小关系或适当的阈值与居民地分开。但道路和居民地在形状上存在明显差异，因此可以利用形状指数的差异加以去除。最后分析建立了基于光谱特征和形状特征的简单决策树模型，对研究区域居民地信息进行了提取并对结果进行了精度评价。结果表明，该方法的总体