车牌定位及倾斜校正方法

提出了一种基于车牌字符信息的车牌定位及其校正方法。首先使用灰度形态学的顶帽操作（top-hat）增强车牌区域,使其能在二值图中突出显示,然后根据二值图中车牌字符的连通元个数和排列位置来确定车牌的具体位置,最后对已定位的车牌进行方向校正,包括水平和垂直方向校正。水平校正是根据这些字符连通元的中心确定车牌的水平倾斜角度,使用旋转几何变换使其水平方向得到校正,垂直校正则使用投影分析的方法求出水平校正后垂直方向的倾斜角度,再进行图像的像素平移。实验结果表明,该方法能够在复杂背景下快速、准确定位到车牌,并且倾斜校正效果很好。     

基于子区域投影分析的车牌倾斜校正

提出一种基于子区域投影分析的车牌倾斜校正方法.首先进行水平倾斜校正,将车牌图像划分为水平方向上的子区域,进行投影分析后确定子区域内字符区域中心点坐标,然后将各中心点拟合为一条直线,直线的倾角即为水平倾角.对于检测垂直倾角,该方法将车牌图像划分为垂直方向上的子区域,利用子区域的投影来快速计算车牌图像的错切变换和垂直投影,确定垂直倾角.实验结果表明,与常用的旋转投影法相比,该方法运算时间少且鲁棒性好.     

基于多颜色模型的车牌定位方法

提出了一种基于多颜色模型的车牌定位方法.首先把输入的RGB彩色图像转化到HSV和YIQ颜色空间,综合这两个颜色空间的信息进行颜色分割去除大量的背景干扰信息,得到了颜色为车牌照的一些区域.然后将颜色分割后的图像灰度化并分块,找出水平差分累加和最大的块确定车牌大致位置在原彩色图中实现车牌的粗定位.最后对粗定位图进行二次颜色分割得到车牌区域的信息利用投影法精确定位出车牌.实验结果表明该方法效果较好.     

一种基于HSV颜色空间和SIFT特征的车牌提取算法

为了克服SIFT算法直接应用在车牌提取中表现出来的执行时间过长、误配率高的缺陷,提出了一种基于HSV颜色空间与SIFT特征的两级车牌提取算法,先使用HSV颜色空间确定车牌的候选区域,进行快速粗定位,再使用SIFT算法对候选区域进行精确定位与倾斜校正,在精确定位的同时也完成了对车牌汉字的辨识。这种方法不仅减少了SIFT特征的计算量,而且也避免了复杂背景对于SIFT特征匹配的干扰,大大提高了匹配准确率。最后通过编程实验证实本算法有良好的性能。     

一种基于灰度图像的车牌定位方法

采用粗定位—倾斜矫正—精确定位三步结合的方法实现车牌定位,克服了由于拍摄角度问题带来的倾斜车牌定位不精确的问题,减少了计算量,继而提高了车牌定位技术中后续的字符分割和识别的精确性。     

一种新的车牌定位与倾斜校正方法

为了在不同条件下对车牌进行定位与倾斜校正,提出了一种基于字符特征匹配的车牌定位与倾斜校正方法。该方法考虑到我国车牌首位字符为汉字的显著特征,利用标准车牌汉字库,采用特征匹配对车牌中的汉字进行定位。由于汉字在我国车牌中的位置严格固定,因此,对汉字的成功定位,也就实现了对整个车牌的定位与倾斜校正。对不同背景、不同光照条件下的车牌进行大量实验,结果表明该方法能够准确地进行车牌定位与倾斜校正,具有良好的鲁棒性。     

基于多颜色模型的车牌定位方法

提出了一种基于多颜色模型的车牌定位方法。首先把输入的RGB彩色图像转化到HSV和YIQ颜色空间,综合这两个颜色空间的信息进行颜色分割去除大量的背景干扰信息,得到了颜色为车牌照的一些区域。然后将颜色分割后的图像灰度化并分块,找出水平差分累加和最大的块确定车牌大致位置在原彩色图中实现车牌的粗定位。最后对粗定位图进行二次颜色分割得到车牌区域的信息利用投影法精确定位出车牌。实验结果表明该方法效果较好。     

复杂背景下的车牌定位和字符分割研究

提出了一种综合边缘检测、投影特征的车牌定位方法和基于垂直投影及模板匹配的字符分割方法,提取车牌灰度图像边缘,实验结果显示该算法检测边缘的速度快,车牌区域轮廓清晰,采用投影法确定车牌区域,用HOUGH变换检测倾斜角度进而对倾斜的车牌进行矫正,通过字符分割算法对车牌字符进行切割,有效地解决了复杂环境的干扰、车牌尺寸变化等问题。对不同背景下的光照车牌进行了大量实验,结果表明该算法能准确地进行车牌定位以及字符分割,具有较好的鲁棒性。     

基于扫描线和特征筛选的车牌定位快速算法

以对车牌识别准确率影响最大的车牌定位技术为重点,研究并提出一种基于扫描线和特征筛选的车牌定位算法,该算法先记录并分析二值图像中相邻水平扫描线上的跳变点信息,确定出候选车牌区域,再根据车牌特征筛选,最终确定车牌区域.对113幅不同车型的图像进行测试,结果表明,去噪处理对定位准确率有很大影响,当车牌倾斜角度小于5°、且经过去噪处理时,定位准确率超过90%,定位时间小于0.9s.     

一种新的车牌倾斜校正方法

车牌的倾斜对车牌的字符分割与识别带来不利的影响.本文分析了车牌的倾斜模式,提出了一种新的车牌倾斜校正方法.该方法采用水平和垂直彩色边缘检测结合旋转投影求取车牌的水平和垂直倾斜角度,对水平倾斜的车牌进行双线性插值旋转校正,对垂直倾斜的车牌进行双线性插值错位偏移校正.实验结果表明,该方法简单实用,对光照、污迹等不敏感,抗干扰能力强.     

基于车牌底色识别的车牌定位方法

提出了结合汽车车牌纹理特征分析和颜色特征分析实现车牌定位的方法。以往的车牌定位技术主要是利用了车牌的纹理特征和形状特征，该文提出的方法是先进行纹理分析和形状分析，再进行色彩分析，从而尽可能多地利用车牌模式识别空间中的各种条件。得到边缘清晰整齐的尽可能小的车牌区域。这种方法明显地克服了单用纹理和形状分析时难以解决的车牌区域变大的问题。     

叠板式多缸薄板成型液压机参数化设计

在已有的300 MN多缸薄板成型液压机的基础上,运用基于VB的SolidWorks二次开发方法与自顶向下完全建模技术,通过驱动模型关键尺寸参数,对新产品进行参数化设计,并用ANSYS仿真优化.通过参数化设计可使该类产品系列化,提高新产品研发速度,促进该类型产品的国产化.     

The quadratic MITC plate and MITC shell elements in plate bending

The analysis of plates can be achieved using the quadratic MITC plate or MITC shell elements. The plate elements have a strong mathematical basis and have been shown to be optimal in their convergence behavior, theoretically and numerically. The shell elements have not (yet) been analyzed mathematically in depth for their rates of convergence, with the plate/shell thickness varying, but have been shown numerically to perform well. Since the shell elements are general and can be used for linear and nonlinear analyses of plates and shells, it is important to identify the differences in the performance of these elements when compared to the plate elements. We briefly review the quadratic quadrilateral and triangular MITC plate and shell elements and study their performances in linear plate analyses.     

Transverse shear effect on vibration of laminated plate using higher-order plate element

An approach using a higher-order plate element to include the effect of transverse shear deformation on free vibration of laminated plate is presented. The total displacement of the element is expressed as the sum of the displacement due to bending and that due to shear deformation. The double-sized stiffness and mass matrices due to the separation of bending and shear displacements are then reduced to the size as if only the total deflection was considered. Numerical results for natural frequencies for a range of different isotropic and anisotropic plates with various thickness-to-length ratios are obtained and compared with solutions available in the literature. The effect of transverse shear deformation on natural frequencies of higher modes of laminated plates is also discussed.     

Simulating tectonic plate movement

In this paper a simulation tool to simulate tectonic plate movement is presented. The purpose is to create a tool which can help analyze and visualize tectonic plate movement and compare different mathematical models. After a short overview of the theory of plate tectonics, the mathematical model and the simulation environment will be described. Finally, an example of a simulation run is given.     

Microchannel plate electro-osmotic pump

Microchannel plate (MCP), a porous glass membrane commonly used as an electron multiplier in particle detectors, has been experimentally investigated here for electro-osmotic pumping characteristics. MCP consists of millions of high-aspect ratio precision identical glass microcapillary tubes fused together. Uniform and straight microchannels in a relatively thick membrane can achieve a maximum flow rate per unit area and voltage ~0.2?mL?min^?1?cm^?2?V^?1 and a maximum pressure per unit voltage ~80?Pa?V^?1. MCP also shows a unique characteristic of directional preference in pumping with net flow consistently induced toward the nearest electrode regardless of polarity of the voltage potential applied.     

Region-based license plate detection

Automatic license plate recognition (ALPR) is one of the most important aspects of applying computer techniques towards intelligent transportation systems. In order to recognize a license plate efficiently, however, the location of the license plate, in most cases, must be detected in the first place. Due to this reason, detecting the accurate location of a license plate from a vehicle image is considered to be the most crucial step of an ALPR system, which greatly affects the recognition rate and speed of the whole system. In this paper, a region-based license plate detection method is proposed. In this method, firstly, mean shift is used to filter and segment a color vehicle image in order to get candidate regions. These candidate regions are then analyzed and classified in order to decide whether a candidate region contains a license plate. Unlike other existing license plate detection methods, the proposed method focuses on regions, which demonstrates to be more robust to interference characters and more accurate when compared with other methods.     

基于Halcon的板式换热器板片质量检测技术研究

提出一种新的板式换热器板片检测方法,应用Halcon图像处理软件中的一系列算子对图像进行处理。获取图像后,先使用边缘检测等方法提取换热器板片的底面区域,之后使用形态学处理等方法提取顶面侧面交界区域,最后使用图像增强、平滑和特征提取等方法获得换热器板片的缺陷区域。该研究为板式换热器板片检测提供了一种新的方法,能够快速、有效地检测出缺陷。     

Modeling flexural plate wave devices

A lumped-parameter model is derived for flexural plate wave (FPW) devices which are rectangular plates or diaphragms with structural layers, a piezoelectric layer, and with interdigitated conducting combs for driving and sensing. This configuration is often used in micromechanical chemical sensors. The model is based an a closed-form solution of a resonating beam; however, the results are applicable to plates supported on four edges. The model gives a voltage or charge output from the sense combs as a function of voltage applied to the drive combs. The analysis predicts the response of the multiple plate modes to axial tensions and to comb finger dimensions and position relative to the diaphragm eigenfunctions. These models are much more detailed than those described in the literature on acoustic chemical sensors and are difficult to obtain by finite-element solutions. Frequency responses of FPW devices constructed from silicon with deposited aluminum nitride as the piezoelectric compared well with analytic results. The effects of boundary conditions on the plate's lateral edges are discussed in both the analysis and testing     

Non-classical plate model for FGMs

Engineering with Computers - In this work, we developed a non-classical plate model for the analysis of the behavior of microplates prepared from functionally graded materials (FGMs). It was...