计算机视觉检测中特征点线提取方法研究

特征点、特征线的提取是计算机视觉检测的基础 ,特别是在工业检测中要求很高的精度。针对这一要求 ,介绍几种提取特征点、特征线的方法 ,具有很高的精度。以采用空心正四面体获取的三角形为例 ,设计一种获得特征点、特征线的图像处理算法 ,该方法具有速度快、精度较高、实用和算法分析容易等优点。实际结果表明 ,用此图像处理方法提取特征点、特征线的误差优于 0 1mm。     

A simple method to find a robust output feedback controller by random search approach

This paper presents a simple but effective method for finding a robust output feedback controller via a random search algorithm. The convergence of this algorithm can be guaranteed. Moreover, the probability to find a solution as well as the number of random trials can be estimated. The robustness of the closed-loop system is improved by the minimization of a given cost function reflecting the performance of the controller for a set of plants. Simulation studies are used to demonstrate the effectiveness of the proposed method.     

A simple method to 'point count' silt using scanning electron microscopy aided by image analysis

This study presents a simple method to ‘point count’ silt‐sized grains using backscattered scanning electron microscopy together with image analysis. The work materialized out of the need to determine the heavy mineral abundance within silt obtained from coastal dunes to aid in the interpretation of dune weathering. This technique allows two broad mineral groups to be quantified according to their modal abundance. The groups are characterized by their dominant atomic elements present; atomic numbers > 20 are classified as ‘high’ (metal oxides, zircon, monazite, carbonates, pyroxenes and amphiboles) and those < 20 as ‘low’ (quartz, feldspars and organics). As a check on this technique, X‐ray fluorescence was used. This showed a strong positive correlation (r² = 0.85) with the developed point counting technique.     

平面四杆导向机构的最优综合方法

选定一种十分理想的Burmester曲线计算方法 ,为给定连杆平面四个相邻位置的导向机构综合问题 ,编制出一套实用的不需提供机构初始位置的计算程序 ,可快速解得许多满足要求的平面四杆机构 ,使选择具有最合适结构、尺寸与传力性能的机构成为可能。该方法容易推广用于传动机构综合和多杆导向机构综合。     

基于区间牛顿法的点到参数曲线最小距离的计算方法

求解点到参数曲线的最小距离常常用一般的搜索算法。针对搜索算法的稳定性和有效性通常不高的问题,基于参数曲线的几何特性,将求最小距离转化为方程求解问题,应用了区间牛顿法来求解方程。研究结果表明,区间牛顿法是一个全局收敛的方程求根算法,具有较高的稳定性。     

雕塑实体计算机视觉建模方法研究

计算机视觉3D重构方法是一种很有前途的几何建模手段。但对于常见的黏土、石膏雕塑模型、传统的计算机视觉算法并不适用,其原因在于缺少表面特征。这里针对这种情况提出了一种新的计算机视觉建模方法。这种方法与CAGD技术紧密结合,首先将物体表面分割为N边域曲面片,经由边缘线提取、匹配,重构出曲面片的边界曲线;然后通过反射模型,图象光亮度分析求出曲面片的跨界切矢;最后综合上述信息,构造出光滑的曲面模型。     

A practical method to detect and correct for lens distortion in the TEM

A practical, offline method for experimental detection and correction for projector lens distortion in the transmission electron microscope (TEM) operating in high-resolution (HR) and selected area electron diffraction (SAED) modes is described. Typical TEM works show that, in the simplest case, the distortion transforms on the recording device, which would be a circle into an ellipse. The first goal of the procedure described here is to determine the elongation and orientation of the ellipse. The second goal is to correct for the distortion using an ordinary graphic program. The same experimental data set may also be used to determine the actual microscope magnification and the rotation between SAED patterns and HR images. The procedure may be helpful in several quantitative applications of electron diffraction and HR imaging, for instance while performing accurate lattice parameter determination, or while determining possible metrical deviations (cell edges and angles) from a given symmetry.     

Accurate estimation of surface roughness from texture features of the surface image using an adaptive neuro-fuzzy inference system

Accurate estimation of surface roughness of workpieces in turning operations play an important role in the manufacturing industry. This paper proposes a method using an adaptive neuro-fuzzy inference system (ANFIS) to establish the relationship between actual surface roughness and texture features of the surface image. The accurate modeling of surface roughness can effectively estimate surface roughness. The input parameters of a training model are spatial frequency, arithmetic mean value, and standard deviation of gray levels from the surface image, without involving cutting parameters (cutting speed, feed rate, and depth of cut). Experiments demonstrate the validity and effectiveness of fuzzy neural networks for modeling and estimating surface roughness. Experimental results show that the proposed ANFIS-based method outperforms the existing polynomial-network-based method in terms of training and test accuracy of surface roughness.     

实现产品图档管理的一种简便而有效的方法

:介绍了一种利用VB及内嵌的数据库引擎技术 ,结合OLE技术设计产品图档数据库 ,实现产品图形数据的存储及与应用程序的链接 ,进而实现产品图档管理 ,构建产品设计环境的简便而有效的方法 ,该法可简化设计人员的操作 ,使其只需关注产品的设计 ,从而提高设计效率     

三偏心蝶阀密封面在位测量的点云数据处理方法

三偏心蝶阀依靠蝶板和阀座密封面的充分面接触实现零泄漏的密封效果,而密封面的加工制造精度对密封性能有着至关重要的作用.现有的密封面测量主要依赖离线测量的方式,存在着测量基准不统一、二次装夹造成的测量误差等问题.本文提出了密封面精密在位测量技术以及原始点云数据处理方法.针对被测密封面,提出波谷-聚类算法和考虑约束条件的法矢...     

A simple method for the use of gallocyanin-chrome alum as an electron stain*

A method has been elaborated for the demonstration of DNA in the electron microscope. The method uses glutaraldehyde fixed tissue pieces from which RNA has been removed by incubation with RNase. DNA is stained by gallocyanin-chrome alum in the tissue block. Embedding and cutting is done in the usual manner. The method is based on histochemical observations at the light microscope level which show sufficient specificity and a good stoichiometry of the staining reaction.     

一种灰度图像基本处理方法及实现方案

这是一种关于灰度图像处理的基本方法．尝试实现了对灰度图像的色阶处理．平滑处理、锐化处理及灰度调整等功能．设计了一套方便使用、针对性强的灰度图像处理软件，并给出了相应的算法代码和数学摸拟实现．实现了图像处理中的一些基本应用．因此可将该方法作为播件修改或添加到其它图像软件中，实现图像识别或模式匹配的预处理功能。     

A simple method of using an internal standard for X-ray microanalysis of microdroplets

The use of an introduced internal standard for the X-ray microanalysis of microdroplets of very small volumes of fluid has hitherto depended on the measurement of equal volumes of sample and standard fluids taken up in a tapered micropipette. It is shown that this difficult procedure can be circumvented by taking up variable volumes of fluids in a constant diameter micropipette. Only the lengths which the fluids occupy in the micropipette need be measured. These parameters are entered into the equation for the thin film model to calculate elemental concentrations. This considerably simplifies the preparation and analysis of microdroplets of biological fluids. Relative elemental sensitivities (k factors) can be reliably obtained either from thin crystals of binary standards or from calibration curves. It is also shown that rapid air-drying of microdroplets incorporating PVP results in crystals of acceptable dimensions for analysis.     

Use of Peldri II (a fluorocarbon solid at room temperature) as an alternative to critical point drying for biological tissues

A new chemical, Peldri II, is evaluated as a compound for drying soft biological tissues for scanning electron microscopy. Peldri II, a fluorocarbon, is a solid at room temperature and is a liquid above 25°C. Cells or tissues are embedded in Peldri II by immersing them in the liquid form and allowing it to solidify. Once solidified, Peldri II will sublime with or without vacuum to dry tissues, probably without introducing surface tension. Several types of cells and tissues have been examined to compare preservation with Peldri II and critical point drying techniques. No differences were detected between the two techniques when normal surface structures were examined. Peldri II appears to be a significant improvement over hexamethyldisilazane as a drying agent for scanning electron microscopy. It is also very convenient for drying large numbers of samples.     

距离编码光栅尺在卧式车床建立参考点中的应用

重点介绍距离编码光栅尺在卧式车床建立参考点时的参数设置和操作方式。通过对距离编码光栅尺结构、原理和实践中的操作参数介绍,为数控机床的灵活性返回零点操作提供了依据。     

A simple method for formation of the matching input in a helical undulator

A helical undulator is widely used in free-electron lasers with pulsed electron beams. An adiabatic input with a length of 5–10 periods is commonly used to inject the beam. A novel and simpler method for matching the undulator input is proposed, theoretically investigated, and experimentally implemented. The end field is formed with the help of wire sections in the form of straight lines and circular arcs, which permits an accurate control of geometrical dimensions. The axial length of this section is ∼1/6 of the undulator period. Experimental results obtained on the undulator with a period of 4.8 cm agree well with theoretical data.     

A simple modification to the LKB 7800 series Knifemaker and a balanced-break method to prepare glass knives for cryosectioning

A novel method of using the LKB 7800 series Knifemaker to produce glass knives using a balanced break is described. The method produces knives of sufficient quality to section aldehyde-fixed, sucrose-cryoprotected, frozen biological material in a cooled cryochamber of an ultramicrotome. The modifications to the Knifemaker are minimal and, if required, the machine can be returned easily to its normal state after use.     

运动平面无限接近位置机构综合的计算机辅助设计

本文用图解解析法，建立了拐点圆、Ｂｏｂｉｌｌｉｅｒ定理、常定曲率圆点（圆心）曲线和Ｂａｌｌ点的数学模型；用简单的数学方法解决了运动平面及其上点的高阶特性机构运动综合的计算机辅助设计问题，并附有程序框图和设计实例。     

A method to determine the mass and coordinates of the center of mass of a body in a given plane

This paper proposes a method to determine the mass and coordinates of the center of mass of bodies that do not have sufficient inherent rigidity. During dynamic trials, the objects being tested take on the properties of independent oscillating systems connected to the measuring bench, which increases the dynamic error of the measurement results. It is proposed to conduct the trials in a centrifugal force field, with the forces having a constant value and direction, by the method of finding the value and position of the rotor unbalance.