基于粒子群优化算法的最大类间方差多阈值图像分割     

周晓伟  葛永慧 《测绘科学》2010,35(2):88-89,122

最大类间方差法是图像分割中一种常用的阈值分割方法,对于单阈值分割具有显著的效果,但是对于多阈值分割,计算复杂度大、耗时较多。本文将粒子群优化算法与最大类间方差法结合,提出了一种新的图像分割方法,该方法利用粒子群优化算法的寻优高效性,并由灰度图像的最大类间方差值作为适应值,搜索最优分割阈值,实现图像的多阈值分割。实验结果显示,新方法大大缩短了寻找最优阈值的时间,降低了运算复杂度,提高了图像分割速度,说明基于粒子群优化算法的图像分割算法是可行的、有效的。  相似文献   

地理编码系统中地名地址分词算法研究   总被引：4，自引：0，他引：4  

张林曼  吴升 《测绘科学》2010,35(2):46-48

对中文分词有关技术进行分析和研究,结合地理编码的特点,设计了基于双字哈希和数组的三层组合分词词典数据结构,以及逐次增字的最大正向分词算法。并通过构建和遍历地名通名词典,识别地名地址中未登录词。测试表明,本文算法速度和效果较好,解决了地理信息系统中中文分词的相关问题。  相似文献   

基于LIDAR数据的建筑物轮廓提取   总被引：2，自引：0，他引：2  

杨洋  张永生  马一薇  胥亚 《测绘科学》2010,35(3):203-205

建筑物轮廓的准确提取是建筑物三维重建中最重要的一步。本文在研究已有建筑物轮廓提取方法的基础上,针对LIDAR离散的点云数据,提出了一种自动快速提取建筑物轮廓信息的方法。首先通过点云数据生成城市的数字表面模型(DSM)和数字地面模型(DTM)相减计算得出规则化的数字表面模型(nDSM),进而将地面点和非地面点进行分类;其次,考虑到地物的几何特性,提出一种8邻域搜索的方法对非地面点点云进行分割,得到建筑物表面点云;最后运用基于梯度图的边界跟踪的方法来获取建筑物的轮廓信息。实验表明:该方法能有效地提取建筑物轮廓。  相似文献   

纹理主方向的遥感影像居民地提取   总被引：1，自引：0，他引：1  

金飞  张占睦  芮杰 《测绘科学》2010,35(4):139-141

本文研究利用基于傅立叶变换和Hough变换的灰度共生矩阵方法对遥感影像居民地进行提取。首先,通过傅立叶变换把遥感影像变换到频率域,然后利用Hough变换找出遥感影像的主纹理方向,进而把影像主纹理方向旋转至水平,最后利用灰度共生矩阵方法进行纹理分割。实验结果表明:基于傅立叶变换和Hough变换的灰度共生矩阵方法对遥感影像居民地有较好的提取结果。  相似文献   

车载激光点云的道路标线提取及语义关联     

姚连璧  秦长才  张邵华  陈启超  阮东旭  聂顺根 《测绘学报》2020,49(4):480-488

自动驾驶技术已成为未来智能交通的发展方向之一,高精度地图为L3级及以上自动驾驶实现高精度定位和路径规划提供先验信息,是自动驾驶车辆传感器在遮挡或观测距离受限情况下的重要补充。道路标线的位置和语义信息,比如实线和虚线的绝对位置是高精度地图的基本组成部分。本文从车载激光点云中提取扫描线,根据道路边缘位置几何形态的突变从扫描线中提取道路路面,在此基础上首先利用反距离加权插值的方法把路面点云图像以一定的分辨率转换为栅格图像,其次利用基于积分图的自适应阈值分割方法把栅格图像转化为二值图像,然后利用欧氏聚类的方法从二值图像中提取标线点云,并利用特征属性筛选的方法对提取的标线点云进行语义识别,最后建立交通标线和交通规则之间的语义关联。  相似文献   

基于目标分割和景观格局特征的城市土地利用分类     

李伟峰  王轶 《国土资源遥感》2011,22(1):118-122

根据相同土地利用类型景观格局特征相似的原理,在传统遥感分类方法的基础上,结合景观生态学理论,建立了土地利用分类新方法; 应用SPOT遥感图像提取了北京市五环内的居民用地和非居民用地类型,总分类精度达到了85.9%,Kappa系数为71.1%.本研究结合学科交叉的优势,为遥感技术应用和土地利用信息提取提供了新思路.  相似文献   

Segmentation of soil roughness profiles     

Lorenzo Borselli 《地球表面变化过程与地形》1999,24(1):71-90

A robust and flexible algorithm to study spatial series like soil roughness profile has been introduced. It avoids using classic spectral analysis, considers the profile first and foremost as non-stationary and makes it possible to identify the separate domains inside the profile where chosen statistical parameters and roughness indexes have their own value. The method analyses a roughness profile considering it as an assemblage of several entities that may differ in terms of statistical properties and length, without establishing constraints as to number and extension. The method derives the variability of statistical and roughness properties along the profile and extracts the possible components - random and oriented - detectable inside the sample. Some examples of application illustrate the possibility offered by the method to study real roughness profiles recorded in the field by a portable laser microprofilometer. The procedure proposed allows the investigation of local roughness properties with varying degrees of accuracy and should be useful to monitor the differential evolution of roughness on patterned soil surface, increasing the overall information content. A general definition of ‘ordered roughness’ is introduced. The definition proposed seems more suited to current techniques for the numerical treatment of digital profiles and for the existing physical relationships between the scale of observation of roughness and the scale of the process investigated (hydraulic resistance, water storage in depressions). Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   

Effect of image segmentation & voxel size on micro-CT computed effective transport & elastic properties     

《Marine and Petroleum Geology》2017

Digital rock technology is rapidly evolving interdisciplinary field with many promises, including fast turnaround times for core analysis, repeatable analysis, and multiphysics simulation. We study the impact of the image segmentation threshold and image voxel size on image-computed permeability, elastic moduli, and electrical conductivity. Improved quantitative understanding of such effects is critically important when comparing laboratory-measured rock properties with those computed on digital images of rocks. We analyze properties of over 500 binary microstructures (each of size 1024³ voxels) segmented using different segmentation algorithms. We find that uncertainty in computed rock properties, induced due to the choice of segmentation threshold, increases with coarsening of image voxels. Segmentation of the same rock, acquired with different voxels sizes, lead to small variations in porosity but induces relatively large variation in flow and electrical rock properties. This uncertainty is larger for rocks of lower porosity. We find that coarsening of image voxels also leads to rounding and smoothing of pore throats and a sharp decline in specific surface area which results in an increase in computed permeability. We propose simple models to remove the bias in rock properties when image-derived porosity is either overestimated or underestimated due to the choice of the segmentation threshold. This approach is particularly useful when comparing laboratory-measured rock properties to those derived from digital rocks since often the image calculated porosity and the laboratory-measured porosity are not the same. Even after such corrections, the impact of finite image voxel size would still need to be compensated.  相似文献   

Numerical estimation of carbonate rock properties using multiscale images          下载免费PDF全文

Mohamed Soufiane Jouini  Sandra Vega  Ahmed Al‐Ratrout 《Geophysical Prospecting》2015,63(2):405-421

Characterizing the pore space of rock samples using three‐dimensional (3D) X‐ray computed tomography images is a crucial step in digital rock physics. Indeed, the quality of the pore network extracted has a high impact on the prediction of rock properties such as porosity, permeability and elastic moduli. In carbonate rocks, it is usually very difficult to find a single image resolution which fully captures the sample pore network because of the heterogeneities existing at different scales. Hence, to overcome this limitation a multiscale analysis of the pore space may be needed. In this paper, we present a method to estimate porosity and elastic properties of clean carbonate (without clay content) samples from 3D X‐ray microtomography images at multiple resolutions. We perform a three‐phase segmentation to separate grains, pores and unresolved porous phase using 19 μm resolution images of each core plug. Then, we use images with higher resolution (between 0.3 and 2 μm) of microplugs extracted from the core plug samples. These subsets of images are assumed to be representative of the unresolved phase. We estimate the porosity and elastic properties of each sample by extrapolating the microplug properties to the whole unresolved phase. In addition, we compute the absolute permeability using the lattice Boltzmann method on the microplug images due to the low resolution of the core plug images. In order to validate the results of the numerical simulations, we compare our results with available laboratory measurements at the core plug scale. Porosity average simulations for the eight samples agree within 13%. Permeability numerical predictions provide realistic values in the range of experimental data but with a higher relative error. Finally, elastic moduli show the highest disagreements, with simulation error values exceeding 150% for three samples.  相似文献   

天绘一号卫星影像的平原绿化提取方法     

尚珂  于信芳  岳彩荣  王乾坤  王正兴 《地球信息科学学报》2015,17(3):361-368

平原绿化是我国平原地区森林植被的主体,为生态环境建设提供了有力保障。但平原绿化分布零散,斑块面积小,不易被准确提取。本文以河南省封丘县为例,利用天绘一号卫星影像面向对象分类技术提取了平原绿化。在面向对象分类过程中,针对不同平原绿化信息选取不同的分割尺度和参数,建立影像对象的分割层次结构,确保农田林网、通道防护林、四旁防护林等平原绿化信息能够被准确分割。分类时通过构建隶属度函数,利用层与层之间的关系,子类继承父类的分类特征,在此基础上增加自己的特征,建立分类规则集,逐层提取绿化信息。本文共获取封丘县平原绿化面积152.51 km²,其中,农田林网36.09 km²,通道防护林21.29 km²,四旁防护林71.56 km²,片林23.57 km²。利用验证点数据,对分类结果进行精度评价,总体分类精度为93.50%,Kappa系数达到0.92。  相似文献