基于灰度形态学的高分辨率遥感影像预处理

提出了一种从高分辨率遥感影像中提取线性目标时影像预处理的方法。该方法基于灰度形态学的Top-Hat运算和灰度膨胀运算，用Top-Hat算子除去影像的噪声，再利用灰度膨胀增强影像目标和背景之间的对比度，使目标更易于识别。经过处理的遥感影像，能够更有效地提取影像的目标。     

基于模糊算子理论的道路半自动提取

提出了一种基于模糊算子理论的道路半自动提取方法。该方法在对小比例尺影像进行Sobel边缘检测的基础上，定义了12种模糊算子表示2维道路的各种可能的结构，然后在给定道路种子点附近形成的一定范围内进行搜索，提取出道路的中心线。实验结果表明，该算法速度较快并且具有较强的鲁棒性。     

GIS数据辅助下的线状目标自动提取

首先介绍了遥感影像中线状目标骨架自动提取的意义和研究现状，然后结合老的GIS数据，提出了一种算法来实现遥感影像中线状目标骨架的自动提取，算法主要包括影像预处理、GIS数据与影像的配准、骨架跟踪、编组连接与数据简化等步骤。最后又利用遥感影像和相应的GIS数据进行了实验，实验证明了算法的可行性和有效性。     

基于光谱空间密度分析的边缘提取

针对传统的边缘提取方法大部分不适应高光谱数据的特点，提出了基于光谱空间密度分析边缘提取的思想。在分组主分量变换提取第一主分量作为特征维的基础上，采用面向对象的二次判别边缘的方法，通过立体判决将光谱空间中低密度超椭球体集群视为真实边缘点集群。试验表明，此方法是合理可行的。     

基于物方影像匹配和概率松弛的断面自动提取

提出了基于物方影像匹配的断面提取,为了提高匹配的可靠性,引入了概率松弛法,最终获得了高精度的断面.     

Anabranching in mixed bedrock-alluvial rivers: the example of the Orange River above Augrabies Falls, Northern Cape Province, South Africa

Anabranching is characteristic of a number of rivers in diverse environmental settings worldwide, but has only infrequently been described from bedrock-influenced rivers. A prime example of a mixed bedrock-alluvial anabranching river is provided by a 150-km long reach of the Orange River above Augrabies Falls, Northern Cape Province, South Africa. Here, the perennial Orange flows through arid terrain consisting mainly of Precambrian granites and gneisses, and the river has preferentially eroded bedrock joints, fractures and foliations to form multiple channels which divide around numerous, large (up to 15 km long and 2 km wide), stable islands formed of alluvium and/or bedrock. Significant local variations in channel-bed gradient occur along the river, which strongly control anabranching style through an influence on local sediment budgets. In relatively long (>10 km), lower gradient reaches (<0.0013) within the anabranching reach, sediment supply exceeds local transport capacity, bedrock usually only crops out in channel beds, and channels divide around alluvial islands which are formed by accretion in the lee of bedrock outcrop or at the junction with ephemeral tributaries. Riparian vegetation probably plays a key role in the survival and growth of these islands by increasing flow roughness, inducing deposition, and stabilising the sediments. Less commonly, channels may form by eroding into once-continuous island or floodplain surfaces. In shorter (<10 km), higher gradient reaches (>0.0013) within the anabranching reach, local transport capacity exceeds sediment supply, bedrock crops out extensively, and channels flow over an irregular bedrock pavement or divide around rocky islands. Channel incision into bedrock probably occurs mainly by abrasion, with the general absence of boulder bedforms suggesting that hydraulic plucking is relatively unimportant in this setting. Mixed bedrock-alluvial anabranching also occurs in a number of other rivers worldwide, and appears to be a stable and often long-lived river pattern adjusted to a number of factors commonly acting in combination: (1) jointed/fractured granitoid rock outcrop; (2) erosion-resistant banks and islands; (3) locally variable channel-bed gradients; (4) variable flow regimes.     

Distribution of trace metals in the Odra River system: Water–suspended matter–sediments

Extensive investigations of trace metals concentrations in water, suspended particulate matter (SPM) and bottom sediments of the whole Odra River system were carried out over the years 1997–2000. The vertical distribution of selected metals and their mobility were also studied in the sediment cores from upper and middle river sections. Significant levels of metal contamination were found. Median concentrations (Cd, Pb, Cu, Zn and As) in the SPM and sediments were (mg kg⁻¹) 7.1 and 8.9 Cd, 128 and 146 Pb, 81 and 119 Cu, 1198 and 1204 Zn, 48 and 54 As, respectively. The highest metal pollution of the Odra River solids was found with cadmium, zinc, lead and arsenic, showing high similarity in their frequency distributions in both SPM and sediments. Cd, Zn and As appear to be of particular concern because of the high levels, that appear to be bioavailable, and their high mobility. The exchangeable and carbonate chemical forms of Cd and Zn reached up to 50% of their total amount. Besides the determination of total metal concentration, the metal chemical forms in river solids were investigated. The results of very wide studies of the Odra River system through 4 years suggest that metal pollution decreased, especially for Zn, Pb and Cu. Among all metals studied in the Odra River sediments, substantial reductions of Cd contamination were observed neither in the period after ’97 flood, nor if compared with the earlier results obtained before ’97. No essential differences of the metal contents were observed among the samples for the same river compartment, from the same locality, taken within the five sampling campaigns. The pattern of spatial and vertical metal distributions in the river solids indicates that a variety of sources might be responsible for the contamination; very intensive, historical and current mining and smelting activities probably are the most important ones.     

Causes for continuous siltation of the lower Yellow River

Previous studies indicate that aggradation of a river channel is caused by upriver and/or downriver controls, but the evaluation of their relative importance is often difficult. A method is proposed to isolate the effect of the downriver control based on the slopes of the existing river profile, those of the graded profile estimated from the discharge-sediment relationship and slope reduction due to local base-level rise. The method was applied to the rapidly aggrading lower Yellow River. The downriver control in this case refers to the local base-level rise associated with deltaic extension during the period under discussion. The result shows that the main portion of siltation along the river is not caused by downriver control but by the slope difference between the existing and the graded profiles over a period within the last 700 years, assuming conditions of discharge and sediment load during the period from 1962 to 1985 are reflective of the long term. The marked slope difference between the existing and the graded profiles of the river is a result of changes in the river environment in the past several thousand years including the increase of sediment load, local base-level rise associated with river lengthening by deltaic growth, and relative sea-level rise due to tectonic subsidence of the coastal alluvial plain.     

Influence of vegetation on aeolian sand transport rate from a backshore to a foredune at Hasaki, Japan

The influence of vegetation on aeolian sediment transport rate in the region from a backshore to a foredune was investigated at the Hasaki Coast in Japan, where an onshore wind was predominant and the creeping beach grasses Carex kobomugi and Calystegia soldanella were major species. The comparison of cross-shore distributions of the cross-shore component of aeolian sand transport rate with and without vegetation, which were estimated on the basis of the beach profile changes and a mass conservation equation, showed that the creeping grasses influenced the aeolian sand transport rate. The landward aeolian sand transport rate rapidly decreased landward from the seaward limit of vegetation when the grasses grew. The aeolian sand transport rate reduced by 95% with a vegetation cover of 28%. On the other hand, when the grasses were absent, the landward aeolian sand transport rate did not decrease near the seaward vegetation limit, but near the foot of the foredune.     

甘肃华亭地区铀矿化信息遥感提取方法

从分析ETM各波段图像的信息特征入手,在黄土覆盖等环境因素干扰严重的地区,利用遥感技术对其铀矿化的信息进行了提取.在ERDAS软件的支持下,应用图像融合、波段比值、主成分分析、光谱指数等技术方法,对ETM遥感影像数据进行增强处理.其中,图像融合与传统的图像融合略有不同,是在进行图像融合前将原始图像（ETM1～5,7）进行低通滤波处理,使得融合后的图像既保留高分辨率数据的空间信息,又保留低分辨率数据的光谱信息.在对研究区的遥感数据进行增强处理后,选取有利波段组合,圈定了有利铀成矿的远景区.