一种深度图像障碍物检测新方法   总被引：2，自引：1，他引：1  

王腾  卜乐平  黄忠义 《测绘科学》2017,42(6)

针对传统障碍物检测技术存在的不足,该文将Kinect深度摄像机作为障碍物检测系统的传感器,在Kinect实时三维重建和Meanshift图像分割的理论基础上,提出了一种基于Kinect深度图像的障碍物检测方法,并针对深度图像随机噪声点多的特点,提出了一种改进的高斯滤波算法.分别在不同环境中进行了障碍物检测实验,实验结果表明该文提出的检测算法能准确检测出复杂场景中的障碍物区域,并对光照具有很强的鲁棒性.  相似文献   

Additional Samples: Where They Should Be Located   总被引：2，自引：0，他引：2  

Pilger  G. G.  Costa  J. F. C. L.  Koppe  J. C. 《Natural Resources Research》2001,10(3):197-207

Information for mine planning requires to be close spaced, if compared to the grid used for exploration and resource assessment. The additional samples collected during quasimining usually are located in the same pattern of the original diamond drillholes net but closer spaced. This procedure is not the best in mathematical sense for selecting a location. The impact of an additional information to reduce the uncertainty about the parameter been modeled is not the same everywhere within the deposit. Some locations are more sensitive in reducing the local and global uncertainty than others. This study introduces a methodology to select additional sample locations based on stochastic simulation. The procedure takes into account data variability and their spatial location. Multiple equally probable models representing a geological attribute are generated via geostatistical simulation. These models share basically the same histogram and the same variogram obtained from the original data set. At each block belonging to the model a value is obtained from the n simulations and their combination allows one to access local variability. Variability is measured using an uncertainty index proposed. This index was used to map zones of high variability. A value extracted from a given simulation is added to the original data set from a zone identified as erratic in the previous maps. The process of adding samples and simulation is repeated and the benefit of the additional sample is evaluated. The benefit in terms of uncertainty reduction is measure locally and globally. The procedure showed to be robust and theoretically sound, mapping zones where the additional information is most beneficial. A case study in a coal mine using coal seam thickness illustrates the method.  相似文献   

Using non-Gaussian distributions in geostatistical simulations     

G. Bourgault 《Mathematical Geology》1997,29(3):315-334

Parametric geostatistical simulations such as LU decomposition and sequential algorithms do not need Gaussian distributions. It is shown that variogram model reproduction is obtained when Uniform or Dipole distributions are used instead of Gaussian distributions for drawing i. i.d. random values in LU simulation, or for modeling the local conditional probability distributions in sequential simulation. Both algorithms yield simulated values with a marginal normal distribution no matter if Gaussian, Uniform, or Dipole distributions are used. The range of simulated values decreases as the entropy of the probability distribution decreases. Using Gaussian distributions provides a larger range of simulated normal score values than using Uniform or Dipole distributions. This feature has a negligible effect for reproduction of the normal scores variogram model but have a larger impact on the reproduction of the original values variogram. The Uniform or Dipole distributions also produce lesser fluctuations among the variograms of the simulated realizations.  相似文献   

基于高斯括号原理的高斯光束传输与变换特性的分析     

何平安  林银森 《武汉大学学报(信息科学版)》1992,(4)

本文基于高斯括号原理,用ABCD定律详细地分析了基模高斯光束经过一般光学系统的传输与变换特性,并以此为基础,就各种典型光学系统及特殊情况作了进一步地讨论,得出了许多有实际应用价值的结论。  相似文献   

一种基于规则的对比度增强方法     

张向前  李晓峰  余旭初 《测绘学院学报》1991,(3)

本文提出了一种基于规则的对比度增强方法;着重对均值和方差变换、规则库的建立和修改、局部增强技术等进行了探讨。实验结果表明,该方法优于大多数传统的图像增强方法。  相似文献   

On counting the number of data pairs for semivariogram estimation     

Max D. Morris 《Mathematical Geology》1991,23(7):929-943

In planning spatial sampling studies for the purpose of estimating the semivariogram, the number of data pairs separated by a given distance is sometimes used as a comparative index of the precision which can be expected from a given sampling design. Because spatial data are correlated, this index can be unreliable. An alternative index which partially corrects for this correlation, themaximum equivalent uncorrelated pairs, is proposed for comparing spatial designs. The index is developed under the assumption that the underlying stochastic process is Gaussian and is appropriate when the (population) semivariogram is to be estimated by the sample semivariogram.  相似文献   

Spectral band selection for vegetation properties retrieval using Gaussian processes regression     

《International Journal of Applied Earth Observation and Geoinformation》2016

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Doppler-shift approximations of encountered wave statistics     

Sofia Aberg  Igor Rychlik 《Ocean Engineering》2007,34(17-18):2300-2310

In this paper the joint density of waveheight and half-wavelength is considered for waves observed at a fixed time point and encountering waves that are overtaking a ship from behind. The densities for these two cases are related by a Doppler shift, expressed in terms of the relative velocity of the waves and the ship. Based on this observation, an approximation of the encountered density is proposed. This approximation is then investigated for a Gaussian sea having a Pierson–Moskowitz spectrum.  相似文献   

Random-walk dynamics of exploited fish populations     

Niwa  Hiro-Sato 《ICES Journal of Marine Science》2007,64(3):496-502

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Maxima for Gaussian seas     

Anastassia Baxevani  Igor Rychlik 《Ocean Engineering》2006,33(7):895-911

The probability distribution of the height of global maximum for a Gaussian random field evolving in time is studied. In particular, the effect of spreading is studied and the role of the wave kinematics is discussed. It is observed that taking into account time dynamics of spatial characteristics results in distributions different from those obtained for the static case. The results are illustrated by computing the derived distribution for different Gaussian seas for three distinct sampling schemes. The resulting distributions are also used to compute return periods for rogue waves.  相似文献