Steerable Pyramid分解在储层断裂检测中的应用

在隐蔽油气藏勘探中,正确刻画储层断裂对于油气勘探和开发都有着至关重要的作用.储层断裂在地震数据中表现为边缘特征.但现今多尺度边缘检测的基本理论和方法都有其本身的局限性.本文详细阐述了Steerable Pyramid分解用于储层断裂检测的基本原理和方法.输入的三维地震切片经过Steerable Pyramid分解后,不仅可以分析不同尺度不同方向上断裂的特征及走向,还可以通过重构得到经S函数控制的断裂信息,该断裂信息不仅仅是断裂的边缘检测,而是增强的断裂本身.将该算法应用于实际地震切片的断裂检测,得到了清晰的断裂信息,完整细致地展现了这些地质类型的特征,为构造解释、地震相表征及储层预测提供了有用信息.

Steerable Pyramid分解地震随机噪声衰减——基于局部Laplace先验概率密度模型

简单介绍了具有多尺度与多方向性特点的Steerable Pyramid分解和重构的基本原理。采用softLMAP阈值将其应用于地震数据随机噪声衰减中,进行了仿真计算和实际资料的处理并与自适应BayesShrink阈值及小波域softLMAP阈值去噪进行比较。结果证明利用Steerable Pyramid分解softLMAP阈值能比较彻底地去掉噪声,去噪后的图像边缘保持良好,滤除噪声同时还保留了有效部分,去噪效果良好,且易于实现,在地震资料处理中具有一定的可行性和应用前景。

Steerable Pyramid分解方法及其在断层检测中的应用

分析了Steerable Pyramid分解用于断层检测的基本原理.输入的三维地震时间切片经过Steerable Pyramid分解后,不仅可以分析不同尺度不同方向上断层的特征及走向,还可以通过重构得到断层信息.该信息不仅是断层的边缘检测,而且将断层直接提取出来.在去除了断层信息后,该方法还可用于河道砂的沉积成像.将该方法应用于一张实际的地震振幅属性切片,结果证明将Steerable Pyramid分解用于储层断层检测与沉积成像是成功的.但是,处理结果对空间平滑参数都很敏感,参数的最优选择要根据输入图像的特征而变.

Steerable Pyramid分解域地震强随机噪声衰减

为解决油气地球物理勘探中地震资料的噪声问题,研究了Steerable Pyramid分解阈值去噪对地震资料强随机噪声背景下弱信号识别的影响。根据地震资料弱信号的Steerable Pyramid分解系数值较小的特点,从Steerable Pyramid分解域硬阈值去噪出发,采用降低阈值的方法保护Steerable Pyramid分解系数值较小的弱信号,同时针对时域噪声残留采用均值平滑的方法保证去噪效果。经过理论模型和实际资料实验,得出在Steerable Pyramid分解域采用硬阈值降阈值+均值滤波的方法可以从较强的噪声背景中识别出弱信号,并且保证信噪比有足够的提高;在去噪的同时,不但连续性好,反射强的同相轴得到了增强,而且即使连续性差,反射弱的同相轴也得到了有效的保留。采用本方法去噪伪影较少,剖面的保真度较高。

基于超复数Steerable滤波器的电力输电线检测方法

提出一种自然场景下基于超复数频域Steerable滤波器的电力输电线检测算法.该算法首先利用二维高斯函数构造超复数Steerable正交对滤波器,然后将构造的滤波器与彩色电力输电线图像进行不同方向的脊能量检测,进而获得输电线脊能量最大方向响应,最后得到电力输电线检测图.实验结果表明,该算法具有较好的方向可控性,对输电线的检测比其他算法精度高且速度快,具有一定的理论和实际应用价值.

Steerable microcatheters for complex percutaneous coronary interventions in octogenarians: from Venture to Swift Ninja

0ctogenarians represent the fastest growing group of patients undergoing percutaneous coronary intervention(PCI),now constituting more than one in five patients treated with PCI in real-world practice.[1,2]Comparing coronary lesion characteristics of patients aged<≥80 years to those≥80 years undergoing PCI,the octogenarians have a higher prevalence of calcified and ostial lesions,tortuous coronary anatomy,multi-vessel disease and left main stem(LMS)stenosis.⑶Furthermore,they often have greater ischemic burden than their younger counterparts,suggesting an even greater benefit following revascularization.

EchoNavigator virtual marker and Agilis NxT steerable introducer facilitate transseptal transcatheter closure of mitral paravalvular leak

BACKGROUND Paravalvular leak(PVL),also known as paravalvular prosthetic regurgitation,is not a rare complication after surgical valve replacement,and it may cause varying degrees of heart failure.The transcatheter closure of PVL is technically demanding and challenging.CASE SUMMARY A 68-year-old man presented with degenerative mitral regurgitation with heart failure,New York Heart Association functional class 3.He received bioprosthetic mitral valve replacement in December 2019.PVL was noted at the location of the aorto-mitral curtain in transesophageal echocardiography without signs of endocarditis or dehiscence of the bioprosthetic valve.Transseptal transcatheter closure of the mitral PVL was performed efficiently using the EchoNavigator virtual marker and Agilis NxT steerable introducer.CONCLUSION This case highlights that the EchoNavigator virtual marker and Agilis NxT steerable introducer can facilitate transseptal transcatheter closure of mitral PVL by reducing the procedure time and contrast media.

STEERABLE ANTENNAS MOVEMENT COMPENSATION FOR HIGH ALTITUDE PLATFORM

High Altitude Platform(HAP) must compensate for relative motion with respect to the ground because of the stratosphere complexity,which is important to guarantee Quality of Service(QoS) in intended coverage area.With analysis on HAP movement models for predicting the geographical coverage in the cases of shift horizontally and vertically,yaw,roll and pitch,the mechanisms of steerable antennas movement compensation are investigated.The mechanism is applied to a scenario of 127 cell architecture,with a cell cluster size of four.By the simulation results of Carrier to Interference Ratio(CIR),the steerable antenna movement compensation mechanism decrease influence of HAP movement and guarantee effective coverage of the service area.

3D Steerable Pyramid分解域地震资料随机噪声衰减

三维地震资料的去噪工作在油气地球物理勘探中处于至关重要的位置.本文分析了3D Steerable Pyramid分解及重构原理,在3D Steerable Pyramid分解域采用硬阈值降阈值+均值滤波的方法对三维地震资料中的随机噪声进行衰减.经过理论模型和实际资料实验,得出无论噪声水平的高低,在3D Steerable Pyramid分解域采用硬阈值降阈值+均值滤波方法均可以从噪声背景中识别出有效信号,并且保证信噪比有足够的提高;在去噪的同时,不但连续性好,反射强的同相轴得到了增强,而且连续性差,反射弱的同相轴也得到了有效的保留.采用本方法去噪伪影较少,数据的保真度较高,去噪结果干净,同相轴连续,波组关系清晰,断块成像清晰、断点干脆.

Steerable filtering in interactive tracing of archaeological linear features using digital true colour aerial images

In this study,a semi-automatic approach to support archaeological line tracing is proposed.The suggested procedure is based on colour and texture information derived from orthorectified RGB digital aerial data and consists of four steps:(1)line sketching;(2)steerable filtering;(3)objects selection;and(4)straight line fitting and vectorisation.Good results were observed by evaluating the algorithm according to trace visibility and integrity,global difficulty and level of feature extraction.Further reliability tests were performed to study poor data initialisation and different annual seasonal land use at the same site.

Investigation into phantom downlinks and development of a prevention algorithm in rotary steerable system

This paper investigated the failure cause of phantom downlinks of a flow rate detection mechanism in a rotary steerable system and developed a prevention algorithm.Downlinking is the process of controlling a drilling tool from the surface by sending commands to downhole.Directional drillers send downlinks to the rotary steerable system to adjust steering parameters to achieve the desired well plan.The downlink demodulation of downhole tools is achieved through the measurement of flow rate and correlation of waveform with predefined command models;downlink acceptance is based on the correlation rate.One case study revealed that phantom downlinks were due to the variation of turbine rotation speed,which was the result of alternator load changes.A prevention algorithm of conducting a signal energy check was proposed and implemented.The algorithm can successfully prevent phantom downlinks that are usually of low-level energy and only accept authentic downlinks.The work improved the downlinking reliability of the rotary steerable system.This methodology can be further applied to other downlink demodulation mechanisms using collar speed or pressure measurement.

基于融合及数学形态学的遥感图像目标检测

提出了一种基于融合及数学形态学的遥感图像目标检测的新方法。在分析了steerable金字塔变换特性的基础上,采用合理的融合规则将两幅遥感图像进行融合,得到了目标更为清晰的增强图像,有利于进一步的目标检测。然后再利用数学形态学方法及目标的特征对融合后的目标进行检测,得到了满意的检测效果,实验结果表明了本文所提方法的有效性。

基于主成分分析和非下采样SPT的多幅图像融合方法

为了将好的高、低频融合规则模型推广到多幅源图像的融合,提出了一种基于主成分分析和非下采样Steerable金字塔变换的多幅图像融合方法.首先,对源图像进行非下采样Steerable金字塔分解,得到低频子带、高频子带及系列带通子带系数.其次,对于低频分解系数采用基于主成分分析的加权融合;而对系列带通子带图像和高频子带图像的分解系数采用基于局部均值方差的选择与加权平均融合,得到融合图像的非下采样Steerable金字塔系数.最后,经过非下采样Steerable金字塔逆变换得到融合图像.通过对可见光与红外图像以及多聚焦图像的两组融合实验,证明了该方法不仅适合多幅图像的融合,而且还可以获得比传统的图像融合方法质量更高的融合图像.

Image edge detection based on beamlet transform

Combining beamlet transform with steerable filters, a new edge detection method based on line gradient is proposed. Compared with operators based on point local properties, the edge-detection results with this method achieve higher SNR and position accuracy, and are quite helpful for image registration, object identification, etc. Some edge-detection experiments on optical and SAR images that demonstrate the significant improvement over classical edge operators axe also presented. Moreover, the template matching result based on edge information of optical reference image and SAR image also proves the validity of this method.

An iris recognition method based on multi-orientation features and Non-symmetrical SVM

A new iris feature extraction approach using both spatial and frequency domain is presented. Steerable pyramid is adopted to get the orientation information on iris images. The feature sequence is extracted on each sub-image and used to train Support Vector Machine (SVM) as iris classifiers. SVM has drawn great interest recently as one of the best classifiers in machine learning, although there is a problem in the use of traditional SVM for iris recognition. It cannot treat False Accept and False Reject differently with different security requirements. Therefore, a new kind of SVM called Non-symmetrical SVM is presented to classify the iris features. Experimental data shows that Non-symmetrical SVM can satisfy various security requirements in iris recognition applications. Feature sequence combined with spatial and frequency domain represents the variation details of the iris patterns properly. The results in this study demonstrate the potential of our new approach, and show that it performs more satis- factorily when compared to former algorithms.

Region-based multisensor image fusion method

Image fusion should consider the priori knowledge of the source images to be fused, such as the characteristics of the images and the goal of image fusion, that is to say, the knowledge about the input data and the application plays a crucial role. This paper is concerned on multiresolution （MR） image fusion. Considering the characteristics of the multisensor （SAR and FLIR etc） and the goal of fusion, which is to achieve one image in possession of the contours feature and the target region feature. It seems more meaningful to combine features rather than pixels. A multisensor image fusion scheme based on K-means duster and steerable pyramid is presented. K-means cluster is used to segment out objects in FLIR images. The steerable pyramid is a multiresolution analysis method, which has a good property to extract contours information at different scales, Comparisons are made with the relevant existing techniques in the literature. The paper concludes with some examples to illustrate the efficiency of the proposed scheme.

Trajectory Control: Directional MWD Inversely New Wellbore Positioning Accuracy Prediction Method

The deviation control of directional drilling is essentially the controlling of two angles of the wellbore actually drilled, namely, the inclination and azimuth. In directional drilling the bit trajectory never coincides exactly with the planned path, which is usually a plane curve with straight, building, holding, and dropping sections in succession. The drilling direction is of course dependant on the direction of the resultant forces acting on the bit and it is quite a tough job to hit the optimum target at the hole bottom as required. The traditional passive methods for correcting the drilling path have not met the demand to improve the techniques of deviation control. A method for combining wellbore surveys to obtain a composite, more accurate well position relies on accepting the position of the well from the most accurate survey instrument used in a given section of the wellbore. The error in each position measurement is the sum of many independent root sources of error effects. The relationship between surveys and other influential factors is considered, along with an analysis of different points of view. The collaborative work describes, establishes a common starting point of wellbore position uncertainty model, definition of what constitutes an error model, mathematics of position uncertainty calculation and an error model for basic directional service.

Practical realization of dual S arm antenna for beam steering applications

A dual S shaped micro strip antenna with a realistic feed is proposed for generation of tilted beam radiation pattern pertaining for beam steering applications. To achieve this, four feeding points are located at a distance of 5.6 mm from the antenna centre. These feeding points when excited one by one generate four tilted beams in four different space quadrants, thus yielding a beam steerable antenna, Importantly, since the proposed antenna is symmetrical in the structure, all the four tilted beams have the same radiation pattern characteristics. A further enhancement of the antenna bandwidth is also achieved using 100-μn capacitive coupling between the feed and the antenna strip.

Tailoring Meta-Liquid Crystal for Larger Tunability

Liquid crystals are pivotal innovations in the field of tunable materials.However,in the millimeter wave band,the relatively low tunability of liquid crystal limits its applicability.A design method utilizing metamaterial characteristics to enhance the tunability of a liquid crystal is proposed.This design method is based on two theoretical models.Both models embed metamaterial structures into a liquid crystal,thus tailoring a new tunable material,namely,a meta-liquid crystal.By appropriately designing the metamaterials to meet the corresponding conditions derived in different models,the tunability of the meta-liquid crystal can be higher than that of the original liquid crystal.An application of beam scanning is provided to verify this method.Two beam steerable antenna arrays are designed,fabricated and investigated.The beam scanning range of the meta-liquid crystal antenna array is much wider than that of the original liquid crystal antenna array,which confirms the enhancement of tunability.Consequently,this work fills the research gap in improving the performance of liquid crystals in the millimeter wave band.Simultaneously,a bridge is established between two significant materials:tunable materials and metamaterials.The results imply that the performance of tunable materials can be manipulated by metamaterials.

A review of bio-inspired needle for percutaneous interventions

Bio-inspired design translates the knowledge of natural or biological structures or behaviors into novel theories and technologies,providing new directions for research and developments.Although the medical needles for percutaneous intervention technology appear to be mature,biomimetic solutions become popular to further facilitate the performance of the medical needles.In this paper,we review the current state of bio-inspired medical needle designs for percutaneous interventions,including a variety of biomimetic mechanisms and insertion strategies.Existing and experimental designs of biomimetic medical needles are classified into five groups with respect to the applications,while their characteristics are identified and discussed.Such classification and discussion will not only provide technical insights into previous studies but also identify undiscovered directions for future research.