共查询到20条相似文献，搜索用时 31 毫秒
1.
Anomaly analysis is used for various geophysics applications such as determination of geophysical structure's location and
border detections. Besides the classical geophysical techniques, artificial intelligence based image processing algorithms
have been found attractive for geophysical anomaly analysis. Recently, cellular neural networks (CNN) have been applied to
geophysical data and satisfactory results are reported. CNN provides fast and parallel computational capability for geophysical
image processing applications due to its filtering structure. The behavior of CNN is defined by two template matrices that
are adjusted by a properly supervised learning algorithm. After training stage for geophysical data, Bouguer anomaly maps
can be processed and analyzed sequentially. In this paper, CNN learning and processing capability have been improved, combining
Wavelet functions and backpropagation learning algorithms. The new architecture is denoted as Wavelet-Cellular Neural networks
(Wave-CNN) and it is employed to analyze Bouguer anomaly maps which are important to extract useful information in geophysics.
At first, Wave-CNN performance is tested on synthetic geophysical data, which are created by a computer environment. Then,
Bouguer anomaly maps of the Dumluca iron ore field have been analyzed and results are reported in comparison to real drilling
results. 相似文献
2.
图像增强技术在重磁图像中的应用 总被引：2，自引：0，他引：2
本文综述了图像增强技术在位场数据中的应用现状，并介绍了两种改进的图像增强技术，用于增强重磁图像特征。一种方法借鉴了直方图平滑化的思想，应用于位场彩色影像的色谱的自动确定。该方法的应用能够使色彩合理地配置，从而保证了图像的视觉效果和分辨率。另一种方法基于改进的Radon变化和梯度计算，用于重磁图像中线性特征的检测和增强。该方法能在变化域中突出显示线性特征，从而有利于线性特征的检测和增强。通过对简单图像和实际资料的应用，表明了两种方法在增强特征中的有效性。 相似文献
3.
烃渗漏效应会在近地表形成磁性蚀变带,因而可以根据磁性蚀变带产生的磁异常寻找油气异常区.为了减少利用磁力资料识别油气渗漏异常的不确定性和多解性,满足多种地学资料集成管理和综合分析的需要,有必要建立一个集数据管理、实时处理、综合评价和制图功能为一体的判别系统.本文对建立判别系统的关键技术进行了讨论.该系统以ArcGIS为二次开发平台,在继承ArcGIS现有功能的基础上,开发了常规位场数据处理方法模块和基于图像处理和分析技术的重磁异常信号增强和特征提取等功能模块,用于实现近地表油气渗漏异常的地球物理检测与判别,能够为油气有利区的确定提供技术支持,有利于提高地球物理数据处理和解释的效率. 相似文献
4.
N. Tholey 《Surveys in Geophysics》2000,21(2-3):209-222
Earth observation techniques provide digital images of the Earth's surface. In the field of environmental applications, image processing techniques can be used to manipulate the data, in particular to display satellite images in gray level or in a color composition, to radiometrically and geometrically preprocess the data, and to extract thematic information, by visual interpretation or by semi-automatic techniques.This paper presents some basic concepts in digital image processing and givesa general overview of the main processing methods that can be applied to derivegeographical information from Earth observation images. 相似文献
5.
位场全张量梯度数据以其信息量大、含有更高频的信号成分,能更好地描述小的异常特征等优点在地球物理领域中得到广泛应用.边界检测是位场解释中不可缺少的任务,需要新的边界探测器来处理位场梯度张量数据.为了充分利用位场梯度张量数据的多信息成分,本文定义了方向总水平导数和加强方向总水平导数,并利用其定义新的边界检测器.为了能同时显示不同振幅大小异常的边界,本文对其进行了归一化处理.通过模型试验,证明了归一化方法能更加清晰准确地显示浅部和深部的地质体边界信息.最后将该边界检测方法用于加拿大圣乔治湾实际测得全张量重力梯度数据和中国朱日和地区的磁异常数据中,并得到了较好的边界检测结果. 相似文献
6.
This study integrates potential gravity and magnetic field data with remotely sensed images and geological data in an effort to understand the subsurface major geological structures in Afghanistan. Integrated analysis of Landsat SRTM data was applied for extraction of geological lineaments. The potential field data were analyzed using gradient interpretation techniques, such as analytic signal (AS), tilt derivative (TDR), horizontal gradient of the tilt derivative (HG-TDR), Euler Deconvolution (ED) and power spectrum methods, and results were correlated with known geological structures.The analysis of remote sensing data and potential field data reveals the regional geological structural characteristics of Afghanistan. The power spectrum analysis of magnetic and gravity data suggests shallow basement rocks at around 1 to 1.5 km depth. The results of TDR of potential field data are in agreement with the location of the major regional fault structures and also the location of the basins and swells, except in the Helmand region (SW Afghanistan) where many high potential field anomalies are observed and attributed to batholiths and near-surface volcanic rocks intrusions.A high-resolution airborne geophysical survey in the data sparse region of eastern Afghanistan is recommended in order to have a complete image of the potential field anomalies. 相似文献
7.
Paolo Dell'Aversana Gianluca Gabbriellini Alfonso Amendola 《Geophysical Prospecting》2017,65(1):146-157
In this paper, we introduce a new method of geophysical data interpretation based on simultaneous analysis of images and sounds. The final objective is to expand the interpretation workflow through multimodal (visual–audio) perception of the same information. We show how seismic data can be effectively converted into standard formats commonly used in digital music. This conversion of geophysical data into the musical domain can be done by applying appropriate time–frequency transforms. Using real data, we demonstrate that the Stockwell transform provides a very accurate and reliable conversion. Once converted into musical files, geophysical datasets can be played and interpreted by using modern computer music tools, such as sequencers. This approach is complementary and not substitutive of interpretation methods based on imaging. It can be applied not only to seismic data but also to well logs and any type of geophysical time/depth series. To show the practical implications of our integrated visual–audio method of interpretation, we discuss an application to a real seismic dataset in correspondence of an important hydrocarbon discovery. 相似文献
8.
V. L. S. BHIMASANKARAM A. G. TARKHOV A. A. NIKITIN S. V. SESHAGIRI RAO 《Geophysical Prospecting》1973,21(3):464-471
Application of statistical methods of analysis of geophysical data is often helpful for the detection of weak anomalies against a noisy background. The processing and analysis of areal geophysical data by two such methods are presented. The advantage of these methods are illustrated with the help of two field examples. 相似文献
9.
Nowadays, geostatistics is commonly applied for numerous gridding or modelling tasks. However, it is still under used and unknown for classical geophysical applications. This paper highlights the main geostatistical methods relevant for geophysical issues, for instance to improve the quality of seismic data such as velocity cubes or interpreted horizons. These methods are then illustrated through four examples. The first example, based on a gravity survey presents how a geostatistical interpolation can be used to filter out a global trend, in order to better define real anomalies. In the second case study, dedicated to refraction surveying, geostatistical filtering is used to filter out acquisition artefacts and identify the main geological structures. The third one is an example of porosity being integrated geostatistically with a seismic acoustic impedance map. The last example deals with geostatistical time to depth conversion; the interest of performing geostatistical simulations is finally discussed. 相似文献
10.
研究适应信息化时代特征的矿产资源潜力制图新技术、新方法对推动矿产资源评价理论与技术的发展具有重要的意义.笔者把GIS技术、图像分类算法和空间统计学理论进行有机集成,在空间统计学的空间结构分析技术和遥感图像纹理分类算法的基础上,提出了一种以综合地学数据（地质、地球物理、地球化学和遥感图像数据等）为基本数据源的矿产资源潜力自动制图方法.该方法的技术流程为：①数据准备,即对地球物理和地球化学勘探数据进行预处理,生成一个物化遥综合图像文件;②图像空间结构性分析和纹理图像生成,以综合地学图像为研究对象,用空间统计学的结构分析技术研究地学数据综合图像的空间结构性,生成纹理图像;③纹理图像多元分类,用实验变差函数纹理分类方法对研究区进行多元分类,生成分类专题图;④分类后处理,用叠置分析修正空间分类结果,生成区域矿产资源潜力分布图. 相似文献
11.
地球物理信号通常在多个尺度段表现尺度不变性,这些不变性起因于不同的地质、地球物理或成矿过程的自相似性. 利用这种在多个尺度段的尺度不变性可以设计多维分形滤波器,滤波所得信号表征了具尺度不变性的地质地球物理或成矿过程,可以用于成矿预测或环境评价. 本文研究了Walsh变换列率空间地球物理信号的列率功率谱密度与列率之间的分形与多维分形关系, 试验证实了大洋钻探、石油以及煤系地层地球物理测井资料在Walsh域的多维分形性质,提出了用于分解地球物理场,提取有用信号并用于矿产资源勘探或环境评价的多维分形W-A模型. 利用波列率域中的多维分形关系构造了W A图解(W-A Plot). 借助W-A图解可以确定最小平方误差（LS）意义下Walsh功率谱变化的不同自相似性的频率分界点,从而用于设计W-A分形滤波器. 这种滤波器可将地球物理场分解成具有不同自相似性的局部场,并且保留原场的各向异性结构. 与通常使用的基于Fourier变换的滤波技术相比,W-A模型具有许多优点：W-A适用于检测地球物理信号中的突变、线性、环状、局部与纹理结构等弱信号. 同时,由于Walsh变换中只有简单的变号(加法与减法),其计算速度远快于建立在复数乘法之上的Fourier变换,所以W-A计算速度远快于Fourier域的滤波方法,可以用于地球物理信号的现场实时处理. 用加拿大Nova-cotia省西南地区的布格重力异常进行了W-A方法的试算,处理结果反映了地质、矿产分布规律,能够很好地进行矿产预测. 相似文献
12.
As part of the resource evaluation and exploration program conducted by Los Alamos Scientific Laboratory for the national Hot Dry Rock (HDR) Geothermal Program, a regional magnetotelluric (MT) survey of New Mexico and Arizona is being performed. The MT lines are being located in areas where the results of analysis of residual gravity anomaly maps of Arizona and New Mexico, integrated with other geologic and geophysical studies indicate the greatest potential for HDR resources.The residual gravity anomalies are derived by applying the concept of predicting gravity anomalies from topography. This can be accomplished by employing reductions similar to those used in some isostatic investigations, in which a regional topographic surface is used as the Bouguer reduction datum. The datum is derived by comparison of various harmonics of Bouguer anomalies and elevations of stations. Topography can be used to predict Bouguer anomalies because of isostatic compensation; the resultant anomalies can be considered high frequency residual anomalies or isostatic anomalies corrected for regional compensation. Such maps have been produced for Arizona, New Mexico, west Texas, and Chihuahua, Mexico.The main objective of the MT project is to produce a regional geoelectric contour map of the pervasive deep electrical conductor within the crust and/or upper mantle beneath the Colorado Plateau and the adjacent Basin and Range Province and Rio Grande Rift. The MT survey consists of 200 sites along several long profiles with site spacing of 15–20 km. Pre-existing available MT data are being integrated with the new data. After the data are processed, a one-dimensional inversion is applied to the sounding curve and used as a starting point for 2-D modeling. Such a project and ultimate map will be of major value in studying the regional geophysics and tectonics of the southwest United States as they now apply to HDR resources in particular and geothermal resources in general.Electrical conductivity anomalies of large areal extent are of particular interest in geothermal exploration. Correlation analysis of large conductive anomalies with other geophysical, geological, and geotectonic data is being performed. Preliminary analysis of the data has suggested several major regions of anomalously shallow high electrical conductivity. Among these is the Aquarius area of northwest Arizona which is the site of a longwavelength residual anomaly low, which when modeled and correlated with other geophysical data can be shown to be possibly related to low density and high temperature in the crust at depths of 20 km or less. Preliminary analysis of MT data indicates the possible existence of a mid-crustal high electrical conductivity anomaly in this same region. 相似文献
13.
14.
A local plane-wave approach of generalized diffraction tomography in heterogeneous backgrounds, equivalent to Kirchhoff summation techniques when applied in seismic reflection, is re-programmed to act as repeated synthetic aperture radar (SAR) imaging for seismic prestack depth migration. Spotlight-mode SAR imaging quickly provides good images of the electromagnetic reflectivity of the ground via fast Fourier transform (FFT)-based signal processing. By calculating only the Green's functions connecting the aircraft to the centre of the illuminated patch, scattering structures around that centre are also recovered. SAR technology requires us to examine seismic imaging from the local point of view, where the quantity and quality of the available information at each image point are what are important, regardless of the survey geometry. When adapted to seismics, a local image of arbitrary size and sampling is obtained by FFT of seismic energy maps in the scattering wavenumber domain around each node of a pre-calculated grid of Green's functions. These local images can be used to generate a classic prestack depth-migrated section by collecting only their centres. However, the local images also provide valuable information around the centre, as in SAR. They can therefore help to pre-analyse prestack depth migration efficiently, and to perform velocity analysis at a very low cost. The FFT-based signal-processing approach allows local, efficient and automatic control of anti-aliasing, noise and resolution, including optimized Jacobian weights. Repeated local imaging could also be used to speed up migration, with interpolation between local images associated with a coarse grid of Green's functions, as an alternative to interpolation of Green's functions. The local images may, however, show distortions due to the local plane-wave approximation, and the velocity variations across their frame. Such effects, which are not necessarily a problem in SAR, should be controlled and corrected to further enhance seismic imaging. Applications to realistic models and to real data show that, despite the distortion effects, the local images can yield similar information to prestack depth migration, including common-image-point gathers for velocity analyses and AVO/AVA effects, at a much lower cost when a small target is considered. 相似文献
15.
In this study, a Markov Random Field (MRF) approach is used to locate source boundary positions which are difficult to identify
from Bouguer gravity and magnetic maps. As a generalized form of Markov Chains, the MRF approach is an unsupervised statistical
model based algorithm and is applied to the analysis of images, particularly in the detection of visual patterns or textures.
Here, we present a dynamic programming based on the MRF approach for boundary detection of noisy and super-positioned potential
anomalies, which are produced by various geological structures. In the MRF method, gravity and magnetic maps are considered
as two-dimensional (2-D) images with a matrix composed of N1 × N2 pixels. Each pixel value of the matrix is optimized in real time with no a priori processing by using two parameter sets; average steering vector (θ) and quantization level (M). They carry information about the correlation of neighboring pixels and the locality of their connections. We have chosen
MRF as a processing approach for geophysical data since it is an unsupervised, efficient model for image enhancement, border
detection and separation of 2-D potential anomalies. The main benefit of MRF is that an average steering vector and a quantization
level are enough in evaluation of the potential anomaly maps. We have compared the MRF method to noise implemented synthetic
potential field anomalies. After satisfactory results were found, the method has been applied to gravity and magnetic anomaly
maps of Gelibolu Peninsula in Western Turkey. Here, we have observed Anafartalar thrust fault and another parallel fault northwest
of Anafartalar thrust fault. We have modeled a geological structure including a lateral fault, which results in a higher susceptibility
and anomaly amplitude increment. We have shown that the MRF method is effective to detect the broad-scale geological structures
in the Gelibolu Peninsula, and thus to delineate the complex tectonic structure of Gelibolu Peninsula. 相似文献
16.
Resolution analysis of geophysical images: Comparison between point spread function and region of data influence measures 总被引：1，自引：0，他引：1
Practical decisions are often made based on the subsurface images obtained by inverting geophysical data. Therefore it is important to understand the resolution of the image, which is a function of several factors, including the underlying geophysical experiment, noise in the data, prior information and the ability to model the physics appropriately. An important step towards interpreting the image is to quantify how much of the solution is required to satisfy the data observations and how much exists solely due to the prior information used to stabilize the solution. A procedure to identify the regions that are not constrained by the data would help when interpreting the image. For linear inverse problems this procedure is well established, but for non‐linear problems the procedure is more complicated. In this paper we compare two different approaches to resolution analysis of geophysical images: the region of data influence index and a resolution spread computed using point spread functions. The region of data influence method is a fully non‐linear approach, while the point spread function analysis is a linearized approach. An approximate relationship between the region of data influence and the resolution matrix is derived, which suggests that the region of data influence is connected with the rows of the resolution matrix. The point‐spread‐function spread measure is connected with the columns of the resolution matrix, and therefore the point‐spread‐function spread and the region of data influence are fundamentally different resolution measures. From a practical point of view, if two different approaches indicate similar interpretations on post‐inversion images, the confidence in the interpretation is enhanced. We demonstrate the use of the two approaches on a linear synthetic example and a non‐linear synthetic example, and apply them to a non‐linear electromagnetic field data example. 相似文献
17.
本文介绍一个把小波多尺度分析、表面刻痕分析以及位场频率域解释理论和反演方法结合起来的数据处理、反演解释和信息提取的方法系统.这一方法系统简称为区域重力场多尺度刻痕分析方法,应用于刻画地壳分层的三维密度结构、地壳变形带分布和构造单元分区.多尺度刻痕分析包含频率域重力场场源分层、重力场小波变换多尺度分解、场源分层深度及密度扰动反演、分层刻痕分析和构造边界定位四个子系统.文中扼要地介绍这四个子系统基本原理、方法技术及应用效果.从地球物理探测到大地构造学发现,是一个多学科综合研究的探索过程.要取得重大研究成果,必须研发和组合来自不同学科的多个新方法技术,使多学科综合研究有宽厚的理论支撑.本文介绍的四个子系统组合的理论支撑分别来自应用数学、地球物理学和信息科学. 相似文献
18.
Miroslav Novotný 《Surveys in Geophysics》2011,32(6):827-855
The refraction CEL09 profile from the CELEBRATION 2000 project intersects the main terranes of the Bohemian Massif in the
NW–SE direction: the Saxothuringian, the Teplá-Barrandian, the Moldanubian and the Moravo-Silesian. In its easternmost part,
it crosses the Western Outer Carpathians overthrust westward onto the Bohemian Massif. Only the first 450 km were surveyed
with the densest deployment of shot points providing data suitable for a reliable geological interpretation. The first-arrival
depth-recursive tomography was applied here to derive a P-wave velocity image of the upper and middle crust (Part A). The
proper interpretation of the obtained velocity features is the subject of the accompanying paper (Part B). The attained resolution
in the velocity image is shown to be superior as compared with the previous CEL09 models based also on the more uncertain
later arrivals of reflection waves. The applied DRTG (depth-recursive tomography on grid) method is based on a regular network
of refraction grid rays generated for iteratively updated starting models. Only the distinct first arrivals with minimum uncertainty
are used for the DRTG inversions to yield the maximum resolution. Thanks to the full control of the data fit by the grid rays
used, the statistical lateral resolution could be determined at single grid depths for the chosen confidence levels. Thus,
the lateral sizes of the anomalies that can be yet resolved are determined in dependence on their depths and their velocity
excesses. The defocusing of the imaged features is studied on the basis of the spatial responses to spike excitation. The
calculated spatial responses also allowed the edge smearing of the velocity anomalies to be assessed. Special attention is
paid to the imaging of low-velocity zones that are usually suppressed by the smoothing measures used in standard tomographic
methods. An improvement was achieved if the smoothing was suggested with regard to the occurrence of the low-velocity zones
repeatedly appearing in higher iterations. The gained deblurring effect concerns both the negative and positive anomalies
as documented on the velocity features interpreted in the accompanying paper. 相似文献
19.
In this paper, we designed a color visualization model for sparse representation of the whole hyperspectral image, in which, not only the spectral information in the sparse representation but also the spatial information of the whole image is retained. After the sparse representation, the color labels of the effective elements of the sparse coding dictionary are selected according to the sparse coefficient and then the mixed images are displayed. The generated images maintain spectral distance preservation and have good separability. For local ground objects, the proposed single-pixel mixed array and improved oriented sliver textures methods are integrated to display the specific composition of each pixel. This avoids the confusion of the color presentation in the mixed-pixel color display and can also be used to reconstruct the original hyperspectral data. Finally, the model effectiveness was proved using real data. This method is promising and can find use in many fields, such as energy exploration, environmental monitoring, disaster warning, and so on. 相似文献
20.
目的利用重磁异常数据微弱信息增强技术识别线性构造的方法,并介绍其实现过程.方法文中提出了一种梯级带滤波增强非线性滤渡技术与Tilt梯度及其水平导数的有效结合,增强放大微弱信息再识别提取线性构造,利用数字图象显示技术成图.结果识别出柴迭木盆地线性构造多条,分析对比柴达木盆地区域地质构造资料及重力解释成果,具有较好的吻合性.为深入研究该地区线性构造、成矿特征、寻找勘探靶区补充了新的证据.结论该方法提取了区域航磁异常资料中的微弱信息,弥补传统方法的不足,对断层边界及异常的边界划定更为准确.梯级带滤波增强技术与Tilt梯度及其水平导数相结合取得良好的解释效果. 相似文献