Aeromagnetic data over the Mamfe Basin have been processed. A regional magnetic gridded dataset was obtained from the Total Magnetic Intensity (TMI) data grid using a 3 × 3 convolution (Hanning) filter to remove ...Aeromagnetic data over the Mamfe Basin have been processed. A regional magnetic gridded dataset was obtained from the Total Magnetic Intensity (TMI) data grid using a 3 × 3 convolution (Hanning) filter to remove regional trends. Major similarities in magnetic field orientation and intensities were observed at identical locations on both the regional and TMI data grids. From the regional and TMI gridded datasets, the residual dataset was generated which represents the very shallow geological features of the basin. Processing this residual data grid using the Source Parameter Imaging (SPI) for magnetic depth suggests that the estimated depths to magnetic sources in the basin range from about 271 m to 3552 m. The highest depths are located in two main locations somewhere around the central portion of the study area which correspond to the area with positive magnetic susceptibilities, as well as the areas extending outwards across the eastern boundary of the study area. Shallow magnetic depths are prominent towards the NW portion of the basin and also correspond to areas of negative magnetic susceptibilities. The basin generally exhibits a variation in depth of magnetic sources with high, average and shallow depths. The presence of intrusive igneous rocks was also observed in this basin. This characteristic is a pointer to the existence of geologic resources of interest for exploration in the basin.展开更多
Mineral exploration is done by different methods. Geophysical and geochemical studies are two powerful tools in this field. In integrated studies, the results of each study are used to determine the location of the dr...Mineral exploration is done by different methods. Geophysical and geochemical studies are two powerful tools in this field. In integrated studies, the results of each study are used to determine the location of the drilling boreholes. The purpose of this study is to use field geophysics to calculate the depth of mineral reserve. The study area is located 38 km from Zarand city called Jalalabad iron mine. In this study, gravimetric data were measured and mineral depth was calculated using the Euler method. 1314 readings have been performed in this area. The rocks of the region include volcanic and sedimentary. The source of the mineralization in the area is hydrothermal processes. After gravity measuring in the region, the data were corrected, then various methods such as anomalous map remaining in levels one and two, upward expansion, first and second-degree vertical derivatives, analytical method, and analytical signal were drawn, and finally, the depth of the deposit was estimated by Euler method. As a result, the depth of the mineral deposit was calculated to be between 20 and 30 meters on average.展开更多
An understanding of the amount and type of aerosols present in the atmosphere is required for the atmospheric correction of satellite imagery. A sensitivity analysis of the atmospheric inputs to the MOD09 software has...An understanding of the amount and type of aerosols present in the atmosphere is required for the atmospheric correction of satellite imagery. A sensitivity analysis of the atmospheric inputs to the MOD09 software has shown that uncertainty in the estimation of Aerosol Optical Depth (AOD) has the greatest impact on the accuracy of atmospheric correction of MODIS data. The MOD09 software used for the generation of surface reflectance products estimates the AOD of the atmosphere at the time of image acquisition. AOD measurements retrieved from MODIS were compared with near-simultaneous AErosol RObotic NETwork (AERONET) data over three sites in Australia, using time-series of MODIS surface reflectance products. The results of the study provide an important independent validation of ACRES MODIS Surface Reflectance Products. This procedure may be applied to long time series MODIS data for estimating the accuracy of MOD09 retrieved AOD.展开更多
Gravity survey was done at the Eburru area to estimate the source depth locations and delineate the fault boundaries using 3D Euler deconvolution. Gravity data was collected using CG-5 gravimeter. Gravity data reducti...Gravity survey was done at the Eburru area to estimate the source depth locations and delineate the fault boundaries using 3D Euler deconvolution. Gravity data was collected using CG-5 gravimeter. Gravity data reductions were done by applying drift correction, latitude correction, free air correction, Bouguer correction and terrain correction to the observed raw data to obtain complete bouguer anomaly (CBA). The CBA data was transferred to Oasis montaj software for Euler deconvolution processing. The 3D Euler deconvolution was carried out to determine and estimate the depth of the density bodies. Euler deconvolution locates the gravity anomaly source and estimates its depth from the gravity observation level. Euler deconvolution was preferred to other filtering methods in this study as solutions are only determined over identified analytic signal peaks, the window size varies according to anomaly size and the final solution involves only a few more precise depth estimates. The Euler deconvolution was performed using structural indices of 0.5, 1.0 and 2.0. Results from this analysis indicated that the CBA values in this study area range from gravity values of -272 mGal to -286 mGal and residual Bouguer anomaly amplitude range between -3 mGal and 3.4 mGal. The 0.5, 1.0 and 2.0 structural indices generated five solutions at depth range of 433 m - 2269 m, 801 m - 1433 m and 1170 m - 2246 m respectively occurring almost at the same locations on gravity highs. The deep structures were observed to occur in the northern part of the study area, and interpreted to be dense intruding masses likely to be trapped by the overlying cap rock at these depths. These could be geothermal heat sources that can be exploited to generate geothermal energy.展开更多
目前,ToF(Time of Flight)三维成像技术在人脸检测、3D目标识别、三维重建等视觉任务领域具有广阔的应用前景。然而,用ToF相机所获得的深度信息往往存在与像素、温度、深度畸变、多径干扰以及背景光相关的噪声干扰。现有的ToF优化算法...目前,ToF(Time of Flight)三维成像技术在人脸检测、3D目标识别、三维重建等视觉任务领域具有广阔的应用前景。然而,用ToF相机所获得的深度信息往往存在与像素、温度、深度畸变、多径干扰以及背景光相关的噪声干扰。现有的ToF优化算法耗时较大且很难保留目标的细节信息,这些问题严重影响了ToF相机的实际应用。针对以上问题,本文提出一种实时的基于振幅图的ToF深度图优化方法。首先通过ToF接收端采集的原始数据生成带有噪声的振幅图像。针对振幅图中的噪声,选用快速高效的双边网格滤波对振幅图进行去噪。然后,利用优化后的振幅图生成掩码以分割出深度图中前景和背景区域。同时,对深度图中的噪声以及误差像素用滤波的方式优化,最后将优化后的深度图和掩码融合生成最终的深度图。实验结果表明,本文所提算法可以实时有效地滤除深度图噪声,去除背景噪声的干扰,同时能很好地保留深度图中目标对象的细节信息。有助于ToF相机拥有更广泛的应用场景。展开更多
随着电力系统中多类型直流线路占比的逐步提升,调度系统与异构平台间的潮流数据交换需求明显增大,亟需研究新形态下交直流混联系统的潮流计算数据生成问题。该文从拓扑转换、网络拓扑分析、设备建模以及数据生成策略4个主要步骤,实现含...随着电力系统中多类型直流线路占比的逐步提升,调度系统与异构平台间的潮流数据交换需求明显增大,亟需研究新形态下交直流混联系统的潮流计算数据生成问题。该文从拓扑转换、网络拓扑分析、设备建模以及数据生成策略4个主要步骤,实现含交直流系统的基于可扩展标记语言的通用信息模型(common information model/extensible markup language,CIM/XML)数据到潮流计算输入数据的转换。首先,该文从设备间开关拓扑的角度,进行深度优先算法(depth first search,DFS)搜索和设备拓扑拼接,实现开关/节点模型到母线/支路模型的转换;其次,在筛选出活拓扑岛、剔除不带电设备后,着重分析了CIM/XML中换流器建模对交直流节点选取的影响,进而提出了直流节点选取规则和具备普适性的直流数据生成策略。最后,以某地调度500kV及以上交直流网络导出的CIM/XML数据为算例,潮流计算结果与数据采集与监视控制系统(supervisory control and data acquisition,SCADA)量测数据比对验证所提策略的有效性。展开更多
仪表着陆系统(Instrument Landing System,ILS)对飞机进近着陆安全起到基础性保障作用。研究航迹偏离刻度(DOT)、调制度差(Difference in Depth of Modulation,DDM)与航迹偏离角三者间的关系可以进一步量化DOT,显示DDM与真实航迹偏离角...仪表着陆系统(Instrument Landing System,ILS)对飞机进近着陆安全起到基础性保障作用。研究航迹偏离刻度(DOT)、调制度差(Difference in Depth of Modulation,DDM)与航迹偏离角三者间的关系可以进一步量化DOT,显示DDM与真实航迹偏离角的数量关联,为飞行事故调查提供量化依据。基于仪表着陆系统原理建立了ILS数字化波形仿真模型;并通过飞行数据进行回归分析,对国内某机场04R跑道的ILS信号进行实例分析,求解了飞机进近阶段DOT、DDM与航迹偏离角间的定量关系;同时讨论了影响飞机进近安全的次级下滑道现象,为飞行数据分析提供了可行的量化计算方法。展开更多
文摘Aeromagnetic data over the Mamfe Basin have been processed. A regional magnetic gridded dataset was obtained from the Total Magnetic Intensity (TMI) data grid using a 3 × 3 convolution (Hanning) filter to remove regional trends. Major similarities in magnetic field orientation and intensities were observed at identical locations on both the regional and TMI data grids. From the regional and TMI gridded datasets, the residual dataset was generated which represents the very shallow geological features of the basin. Processing this residual data grid using the Source Parameter Imaging (SPI) for magnetic depth suggests that the estimated depths to magnetic sources in the basin range from about 271 m to 3552 m. The highest depths are located in two main locations somewhere around the central portion of the study area which correspond to the area with positive magnetic susceptibilities, as well as the areas extending outwards across the eastern boundary of the study area. Shallow magnetic depths are prominent towards the NW portion of the basin and also correspond to areas of negative magnetic susceptibilities. The basin generally exhibits a variation in depth of magnetic sources with high, average and shallow depths. The presence of intrusive igneous rocks was also observed in this basin. This characteristic is a pointer to the existence of geologic resources of interest for exploration in the basin.
文摘Mineral exploration is done by different methods. Geophysical and geochemical studies are two powerful tools in this field. In integrated studies, the results of each study are used to determine the location of the drilling boreholes. The purpose of this study is to use field geophysics to calculate the depth of mineral reserve. The study area is located 38 km from Zarand city called Jalalabad iron mine. In this study, gravimetric data were measured and mineral depth was calculated using the Euler method. 1314 readings have been performed in this area. The rocks of the region include volcanic and sedimentary. The source of the mineralization in the area is hydrothermal processes. After gravity measuring in the region, the data were corrected, then various methods such as anomalous map remaining in levels one and two, upward expansion, first and second-degree vertical derivatives, analytical method, and analytical signal were drawn, and finally, the depth of the deposit was estimated by Euler method. As a result, the depth of the mineral deposit was calculated to be between 20 and 30 meters on average.
文摘An understanding of the amount and type of aerosols present in the atmosphere is required for the atmospheric correction of satellite imagery. A sensitivity analysis of the atmospheric inputs to the MOD09 software has shown that uncertainty in the estimation of Aerosol Optical Depth (AOD) has the greatest impact on the accuracy of atmospheric correction of MODIS data. The MOD09 software used for the generation of surface reflectance products estimates the AOD of the atmosphere at the time of image acquisition. AOD measurements retrieved from MODIS were compared with near-simultaneous AErosol RObotic NETwork (AERONET) data over three sites in Australia, using time-series of MODIS surface reflectance products. The results of the study provide an important independent validation of ACRES MODIS Surface Reflectance Products. This procedure may be applied to long time series MODIS data for estimating the accuracy of MOD09 retrieved AOD.
文摘Gravity survey was done at the Eburru area to estimate the source depth locations and delineate the fault boundaries using 3D Euler deconvolution. Gravity data was collected using CG-5 gravimeter. Gravity data reductions were done by applying drift correction, latitude correction, free air correction, Bouguer correction and terrain correction to the observed raw data to obtain complete bouguer anomaly (CBA). The CBA data was transferred to Oasis montaj software for Euler deconvolution processing. The 3D Euler deconvolution was carried out to determine and estimate the depth of the density bodies. Euler deconvolution locates the gravity anomaly source and estimates its depth from the gravity observation level. Euler deconvolution was preferred to other filtering methods in this study as solutions are only determined over identified analytic signal peaks, the window size varies according to anomaly size and the final solution involves only a few more precise depth estimates. The Euler deconvolution was performed using structural indices of 0.5, 1.0 and 2.0. Results from this analysis indicated that the CBA values in this study area range from gravity values of -272 mGal to -286 mGal and residual Bouguer anomaly amplitude range between -3 mGal and 3.4 mGal. The 0.5, 1.0 and 2.0 structural indices generated five solutions at depth range of 433 m - 2269 m, 801 m - 1433 m and 1170 m - 2246 m respectively occurring almost at the same locations on gravity highs. The deep structures were observed to occur in the northern part of the study area, and interpreted to be dense intruding masses likely to be trapped by the overlying cap rock at these depths. These could be geothermal heat sources that can be exploited to generate geothermal energy.
文摘目前,ToF(Time of Flight)三维成像技术在人脸检测、3D目标识别、三维重建等视觉任务领域具有广阔的应用前景。然而,用ToF相机所获得的深度信息往往存在与像素、温度、深度畸变、多径干扰以及背景光相关的噪声干扰。现有的ToF优化算法耗时较大且很难保留目标的细节信息,这些问题严重影响了ToF相机的实际应用。针对以上问题,本文提出一种实时的基于振幅图的ToF深度图优化方法。首先通过ToF接收端采集的原始数据生成带有噪声的振幅图像。针对振幅图中的噪声,选用快速高效的双边网格滤波对振幅图进行去噪。然后,利用优化后的振幅图生成掩码以分割出深度图中前景和背景区域。同时,对深度图中的噪声以及误差像素用滤波的方式优化,最后将优化后的深度图和掩码融合生成最终的深度图。实验结果表明,本文所提算法可以实时有效地滤除深度图噪声,去除背景噪声的干扰,同时能很好地保留深度图中目标对象的细节信息。有助于ToF相机拥有更广泛的应用场景。
文摘随着电力系统中多类型直流线路占比的逐步提升,调度系统与异构平台间的潮流数据交换需求明显增大,亟需研究新形态下交直流混联系统的潮流计算数据生成问题。该文从拓扑转换、网络拓扑分析、设备建模以及数据生成策略4个主要步骤,实现含交直流系统的基于可扩展标记语言的通用信息模型(common information model/extensible markup language,CIM/XML)数据到潮流计算输入数据的转换。首先,该文从设备间开关拓扑的角度,进行深度优先算法(depth first search,DFS)搜索和设备拓扑拼接,实现开关/节点模型到母线/支路模型的转换;其次,在筛选出活拓扑岛、剔除不带电设备后,着重分析了CIM/XML中换流器建模对交直流节点选取的影响,进而提出了直流节点选取规则和具备普适性的直流数据生成策略。最后,以某地调度500kV及以上交直流网络导出的CIM/XML数据为算例,潮流计算结果与数据采集与监视控制系统(supervisory control and data acquisition,SCADA)量测数据比对验证所提策略的有效性。
文摘仪表着陆系统(Instrument Landing System,ILS)对飞机进近着陆安全起到基础性保障作用。研究航迹偏离刻度(DOT)、调制度差(Difference in Depth of Modulation,DDM)与航迹偏离角三者间的关系可以进一步量化DOT,显示DDM与真实航迹偏离角的数量关联,为飞行事故调查提供量化依据。基于仪表着陆系统原理建立了ILS数字化波形仿真模型;并通过飞行数据进行回归分析,对国内某机场04R跑道的ILS信号进行实例分析,求解了飞机进近阶段DOT、DDM与航迹偏离角间的定量关系;同时讨论了影响飞机进近安全的次级下滑道现象,为飞行数据分析提供了可行的量化计算方法。
