改进全卷积网络方法的高分二号影像农村道路提取

针对目前利用高分遥感数据提取农村道路的研究与应用少,提取结果精准度不够的问题,提出了结合空洞卷积和ASPP（Atrous Spatial Pyramid Pooling）结构的改进全卷积农村道路提取网络模型DC-Net（Dilated Convolution Network）。该模型基于全卷积的编解码结构来提取道路深度特征信息,同时针对农村道路细长的特点,在解编码层之间加入了以空洞卷积为基础的ASPP（Atrous Spatial Pyramid Pooling）结构来提取道路的多尺度特征信息,在不牺牲特征空间分辨率的同时扩大了特征感受野FOV（Field-of-View）,从而提高细窄农村道路的识别率。以长株潭城市群郊区部分区域为试验对象,以高分二号国产卫星遥感影像为实验数据,将本文提出的方法与经典的几种全卷积网络方法进行实验结果对比分析。实验结果表明：（1）本文所提出的道路提取模型DC-Net在农村道路的提取上具有可行性,整体提取平均精度达到98.72%,具有较高的提取精度;（2）对比几种经典的全卷积网络模型在农村道路提取上的效果,DC-Net在农村道路提取的精度和连结性、以及树木和阴影的遮挡方面,均表现出了较好的提取结果;（3）本文提出的改进全卷积网络道路提取模型能够有效地提取高分辨率遥感影像中农村道路的特征信息,总体提取效果较好,为提高基于国产高分影像的农村道路提取精度提供了一种新的思路和方法。     

融合SAR和TM图像更新GIS道路网络数据

遥感作为空间数据获取的一种手段,其在空间数据更新中的作用显得越来越重要,遥感数据已逐渐成为空间数据更新的主要数据来源。提出一种利用遥感图像自动更新GIS道路网络数据的方法,通过融合两种传感器图像数据,将整个道路网络准确完整地提取出来,然后通过线性特征的变化检测确定已修改的道路及新修建的道路。实验结果表明该方法可以准确地更新道路网络数据。     

An Integrated Multistage Framework for Automatic Road Extraction from High Resolution Satellite Imagery

Automated procedures to rapidly identify road networks from high-resolution satellite imagery are necessary for modern applications in GIS. In this paper, we propose an approach for automatic road extraction by integrating a set of appropriate modules in a unified framework, to solve this complex problem. The two main properties of roads used are: (1) spectral contrast with respect to background and (2) locally linear path. Support Vector Machine is used to discriminate between road and non-road segments. We propose a Dominant singular Measure (DSM) for the task of detecting linear (locally) road boundaries. This pair of information of road segments, obtained using Probabilistic SVM (PSVM) and DSM, is integrated using a modified Constraint Satisfaction Neural Network. Results of this integration are not satisfactory due to occlusion of roads, variation of road material, and curvilinear pattern. Suitable post-processing modules (segment linking and region part segmentation) have been designed to address these issues. The proposed non-model based approach is verified with extensive experimentations and performance compared with two state-of-the-art techniques and a GIS based tool, using multi-spectral satellite images. The proposed methodology is robust and shows superior performance (completeness and correctness are used as measures) in automating the process of road network extraction.     

国产高分辨率遥感影像农村公路核查方法及其应用

传统的农村公路核查需要人工实地抽查或通过GNSS设备进行信息采集验核,存在成本高、效率低等问题。遥感影像具有成像范围广、时效性高、成本低、能客观反映现实情况等优点。相比于传统方法,将遥感影像引入农村公路核查,能客观、准确、高效地对农村公路相关信息进行核查。本文基于国产高分辨率遥感影像,结合农村公路遥感核查业务,采用遥感影像道路提取算法,设计并实现了一种农村公路核查方法。将本方法应用于某中部省份农村公路遥感核查业务,实际应用表明该方法能有效提高现有农村公路遥感核查的工作效率。     

Automatic main road extraction from high resolution satellite imageries by means of particle swarm optimization applied to a fuzzy-based mean calculation approach

Manual extraction of road network by human operator is an expensive and time-consuming procedure. Alternatively, automation of the extraction process would be a great advancement. For this purpose, an automatic method is proposed to extract roads from high resolution satellite images. In this study, using few samples from road surface, a particle swarm optimization is applied to a fuzzy-based mean calculation system to obtain road mean values in each band of high resolution satellite colour images. Then, the images are segmented using the calculated mean values from the fuzzy system. Optimizing the fuzzy cost function by particle swarm optimization enables the fuzzy approach to be the best mean value of road with sub-grey level precision. Initially, this method was applied to simulated images where the calculated mean values are consistent with the hypothetic mean values. Application of the method to IKONOS satellite images has shown a prospective outcome for automatic road extraction. Mathematical morphology is subsequently used to extract an initial main road centreline from the segmented image. Then, small redundant segments are automatically removed. The quality of the extracted road centreline indicates the effectiveness of the proposed approach.     

改进剖面匹配和EKF对SAR影像道路半自动提取

道路提取作为典型的线状目标提取,是遥感影像目标解译的研究热点。合成孔径雷达（SAR）影像包含了丰富的物理特性,能够全天时、全天候地获取影像数据,已广泛应用于道路提取中。传统的道路提取方法分为全自动和半自动方法。全自动道路提取会出现漏检和错检,需要大量的人工后处理。半自动方法结合人工干预,是对计算机的计算能力和人工解译准确性的有效折中。提出了用一种改进剖面匹配和扩展卡尔曼滤波（EKF）的方法对SAR影像道路进行半自动提取的方法。首先构建了道路提取模型,其次通过改进剖面匹配算法获取准确的观测值,最后利用EKF对观测值进行更新获取道路最优估计值。选取美国缅因州Howland地区L波段UAVSAR数据和海南陵水地区X波段机载SAR数据进行实验,结果表明,该方法在较少人工干预的情况下,能够对复杂场景道路进行有效稳健的提取。     

Methodology of Maintenance Criteria of PMGSY Roads in Second Phase of Planning-A Case Study

Present paper focuses on the development of a planning model for upgradation of rural roads keeping Pradhan Mantry Gram Sadak Yoyna (PMGSY) program as the base of this model. Database for the PMGSY roads of Gandevi block of Navasari district in Gujarat state is prepared which includes data like village data, road network & traffic data. Core network is prepared for all the villages under study which can be defined as rural network required for providing ‘basic accesses to all villages. i.e. all villages are connected nearby market centre and essential places from all weather roads. Planning model is classified in two phases. First phase is the network planning and the second phase is upgradation of roads. For the network planning utility values of the villages is calculated by using Delphi technique and on the basis of that alternative routes are decided. For the upgradation of existing roads, Pavement Condition Index (PCI) value of each road is determined and based on these values upgradation of roads are priorities. The rural road network planning methodology for PMGSY roads based on the accessibility concept is presented in this paper and implemented using Geographic Information System (GIS) technology.     

Automatic Road Extraction from High Resolution Satellite Image using Adaptive Global Thresholding and Morphological Operations

Road network extraction from high resolution satellite images is one of the most important aspects. In the present paper, research experimentation is carried out in order to extract the roads from the high resolution satellite image using image segmentation methods. The segmentation technique is implemented using adaptive global thresholding and morphological operations. Global thresholding segments the image to fix the boundaries. To compute the appropriate threshold values several problems are also analyzed, for instance, the illumination conditions, the different type of pavement material, the presence of objects such as vegetation, vehicles, buildings etc. Image segmentation is performed using morphological approach implemented through dilation of similar boundaries and erosion of dissimilar and irrelevant boundaries decided on the basis of pixel characteristics. The roads are clearly identifiable in the final processed image, which is obtained by superimposing the segmented image over the original enhanced image. The experimental results proved that proposed approach can be used in reliable way for automatic detection of roads from high resolution satellite image. The results can be used in automated map preparation, detection of network in trajectory planning for unmanned aerial vehicles. It also has wide applications in navigation, computer vision as a predictor-corrector algorithm for estimating the road position to simulate dynamic process of road extraction. Although an expert can label road pixels from a given satellite image but this operation is prone to errors. Therefore, an automated system is required to detect the road network in a high resolution satellite image in a robust manner.     

Automatic urban road extraction using airborne laser scanning/altimetry and high resolution satellite data

Automatic road extraction from remotely sensed images has been an active research in urban area during last few decades. But such study becomes difficult in urban environment due to mix of natural and man-made features. This research explores methodology for semiautomatic extraction of urban roads. An integrated approach of airborne laser scanning (ALS) altimetry and high-resolution data has been used to extract road and differentiate them from flyovers. Object oriented fuzzy rule based approach classifies roads from high resolution satellite images. Complete road network is extracted with the combination of ALS and high-resolution data. The results show that an integration of LiDAR data and IKONOS data gives better accuracy for automatic road extraction. The method was applied on urban area of Amsterdam, The Netherlands.     

Application of Remote Sensing and Geographic Information System in infrastructure development

Road transportation network development is a vital component of infrastructure development. Absence of database on roads of Trivandrum district was felt as a major hindrance in prioritizing improvement/development/repair of the roads for better traffic efficacy. High resolution PAN imagery (IRS-IC, September-December 1999, 1:25,000 scale) was visually interpreted to decipher road net work for preparing an elaborate database for Kerala Highway. The data were incorporated on 1:25,000 scale SOI base maps. Field verification was carried out to identify and categorize the PWD roads as per their administrative sections. Final maps were digitized in ARC/INFO environment. Information about terrain conditions was also generated using satellite remote sensing images and aerial photographs. Incorporating the height source and elevation data in the value field and taking mass points as input, a TIN (Triangulated Irregular Network) model of a sample area near Vellanad, 22 km east of Trivandrum city was created to analyse the terrain-road network interrelationship. Our case study involving draping of road network on TIN model as well as on geomorphology map established that this methodology could be used to define alternative and efficient route corridors, with particular emphasis on selection of the least-cost route and prioritization of repair.     

Self-organised clustering for road extraction in classified imagery

The extraction of road networks from digital imagery is a fundamental image analysis operation. Common problems encountered in automated road extraction include high sensitivity to typical scene clutter in high-resolution imagery, and inefficiency to meaningfully exploit multispectral imagery (MSI). With a ground sample distance (GSD) of less than 2 m per pixel, roads can be broadly described as elongated regions. We propose an approach of elongated region-based analysis for 2D road extraction from high-resolution imagery, which is suitable for MSI, and is insensitive to conventional edge definition. A self-organising road map (SORM) algorithm is presented, inspired from a specialised variation of Kohonen's self-organising map (SOM) neural network algorithm. A spectrally classified high-resolution image is assumed to be the input for our analysis. Our approach proceeds by performing spatial cluster analysis as a mid-level processing technique. This allows us to improve tolerance to road clutter in high-resolution images, and to minimise the effect on road extraction of common classification errors. This approach is designed in consideration of the emerging trend towards high-resolution multispectral sensors. Preliminary results demonstrate robust road extraction ability due to the non-local approach, when presented with noisy input.     

白忱鹤迁徙路径与地面条件变化信息的遥感监测

据两千多年来的文字记载 ,候鸟适应了地球系统的气候环流、地表温度和湿地生态系统的分布与季节变化 ,选择了迁徙这种生存方式 ,幼年候鸟在迁徙往返中成长 ,候鸟种群在千里迁徙中优胜劣汰。传统监测候鸟迁徙路线的方法普遍采用的是环志法 ,这种方法的回收率为 1 0 %左右。近年来 ,我们与北海道环境研究所、东京大学 ,围绕鹤类鸟迁徙路径及其地面条件变化问题 ,开展了卫星跟踪数据、遥感成像数据、地表温度数据收集、处理和分析 ,得到了初步的结果。这项研究对中国东部经济快速发展地区和待振兴的东北老工业区的布局和发展 ,以及候鸟保护提供科学依据。本文主要介绍了具有代表性的候鸟 ,白忱鹤的迁徙路径监测和分析结果。     

A rule-based parameter aided with object-based classification approach for extraction of building and roads from WorldView-2 images

Roads and buildings constitute a significant proportion of urban areas. Considerable amount of research has been done on the road and building extraction from remotely sensed imagery. However, a few of them have been concentrating on using only spectral information. This study presents a comparison between three object-based models for urban features’ classification, specifically roads and buildings, from WorldView-2 satellite imagery. The three applied algorithms are support vector machines (SVMs), nearest neighbour (NN) and proposed rule-based system. The results indicated that the proposed rules in this study, despite the spectral complexity of land cover types, performed a satisfactory output with an overall accuracy of 92.92%. The advantages offered by the proposed rules were not provided by other two applied algorithms and it revealed the highest accuracy compared to SVM and NN. The overall accuracy for SVM was 76.76%, which is almost similar to the result achieved by NN (77.3%).     

像元与对象特征融合的高分辨率遥感影像道路中心线提取

提出了一种融合像元-多尺度对象级特征的高分辨率遥感影像道路中心线提取方法。首先在像素级上提取影像的纹理和形状结构特征,在构建的多尺度分割集影像上提取对象的区域光谱特征。然后,将像元级特征与多尺度对象特征进行决策级融合,完成道路网的粗提取。最后,结合本文所提出的非道路区域自动去除算法和张量投票算法,实现道路中心线的精提取。不同场景、不同分辨率数据下开展的试验结果表明,该方法可有效改善传统道路提取方法易产生的"盐噪声"和非道路地物粘连现象。     

基于对象直方图G统计量的遥感影像道路提取

提出了一种基于对象直方图G统计量的遥感影像道路提取方法。首先基于标记分水岭算法分割高分辨率遥感影像获取对象像斑,提取对象光谱特征并利用SVM从影像中分离出光谱相似的建成区（道路、建筑物等）;然后从建成区选择合适的对象作为训练样本,采用G统计量度量测试样本与训练样本的LBP纹理直方图距离,以表达对象纹理特征的异质性,并利用最小距离分类器完成建成区内道路与建筑物等的分离;最后结合几何形状特征和数学形态学处理对提取的道路进行优化,获得最终的道路提取结果。试验结果表明：该方法能较好地提取出道路信息。     

一种基于小波变换的遥感影像道路自动提取方法

遥感影像上道路的自动提取是摄影测量与遥感、计算机视觉等领域的重要课题。本文通过对图像小波系数的分析,完成道路节点的提取。随后利用基于小波变换的边缘提取算子,对道路进行边缘提取。边缘提取出来之后,以道路节点为种子点,对道路进行Snake跟踪。为保证提取效果,对图像进行了预处理。实验表明,利用本文提出的理论与方法能为道路网的自动提取与识别提供一个可靠的依据,同时也对其他地物（如建筑物）的自动提取提供一个有价值的参考。     

Rural Road Surface Extraction Using Mobile LiDAR Point Cloud Data

The existing roadway infrastructures are mostly archived with two-dimensional (2D) drawings that lack the possibility for three-dimensional (3D) interpretation and advanced 3D analysis. The mobile LiDAR system (MLS) is gaining popularity in 3D mapping applications along various types of road corridors. MLS achieves the highest data quality and completeness among the traditional roadway data collection methods. The rural roads in different countries especially in India form a substantial portion of the road network. Therefore the proper maintenance and road safety analysis of rural roads are recommended activity, which could be addressed using detailed 3D road surface information. The absence of raised curb at road boundary, and presence of complexity, heterogeneity and occlusions along the rural roadway settings restrict the use of existing studies for road surface extraction using MLS point cloud data. Therefore considering the above requirement, this research paper proposes a two-stage method. The first stage extract planar ground surfaces which are further used to filter road surface in the second stage. Global properties of road, that is, topology and smoothness and its radiometric response to laser beam of MLS are used in the second stage. MLS point cloud data of rural roadway were used to test the proposed method. The road surface points were accurately extracted without being affected by the absence of raised curb and hanging objects over the road surface, that is, tree canopies and overhead power lines. The quantitative assessment of the proposed method was performed in terms of correctness, completeness and quality, which were 96.3, 94.2, and 90.9%, respectively.     

A cognitive framework for road detection from high-resolution satellite images

Road network extraction from high-resolution satellite (HRS) imagery is a complex task. It is an important field of research and is widely used in various cartographic applications such as updating and generating maps. The objective of this research work is to develop a novel framework, emulating human cognition, for detection of roads from HRS images. Roads network from HRS images are detected using support vector machines within the different stages of cognitive task analysis. In the first stage, basic information about the cognitive parameters which are required for image interpretation is collected. In the second stage, the rule-based method is used for knowledge representation. Lastly, during knowledge elicitation, the developed rules are used to extract roads from HRS images. The proposed method is validated using 16 HRS images of developed suburban, developed urban, emerging suburban and emerging urban region.     

Improving urban road extraction in high-resolution images exploiting directional filtering, perceptual grouping, and simple topological concepts

In this letter, the problem of detecting urban road networks from high-resolution optical/synthetic aperture radar (SAR) images is addressed. To this end, this letter exploits a priori knowledge about road direction distribution in urban areas. In particular, this letter presents an adaptive filtering procedure able to capture the predominant directions of these roads and enhance the extraction results. After road element extraction, to both discard redundant segments and avoid gaps, a special perceptual grouping algorithm is devised, exploiting colinearity as well as proximity concepts. Finally, the road network topology is considered, checking for road intersections and regularizing the overall patterns using these focal points. The proposed procedure was tested on a pair of very high resolution images, one from an optical sensor and one from a SAR sensor. The experiments show an increase in both the completeness and the quality indexes for the extracted road network.     

基于灰度和方向一致性的遥感影像道路网提取

从遥感影像中提取道路网是一个经典课题,根据遥感影像中的道路具有灰度和方向一致性的特征,提出一种从遥感影像中提取道路网的新方法。首先根据遥感影像的灰度信息和方向方差信息建立灰度和方向一致性准则分割模型,由此可从遥感影像中提取基本的道路网轮廓,然后再针对道路区域存在非道路点:空洞和裂缝等情况,采用膨胀、腐蚀等操作去除杂乱物块,最后通过数学形态学操作提取出道路网。实验结果表明,该方法能够适用道路、建筑物、植被等多种复杂地物的城市遥感影像中提取道路网,且能获得较好地提取效果。