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目的:医学超声立体成像是超声三维成像的一种实现方法,它能够直观的显示人体内部组织器官的情况,但超声数据的声学噪声以及数据质量严重退化的特点导致成像图像质量较差,严重影响了该技术的应用和发展。因此本文提出一种新的算法来解决这一问题。方法:提出了一种新的度量非稳定度的数据增强算法,该算法能够突出图像变化较大的部分,例如边缘。从而实现对超声数据的增强。结果:通过兔子肝脏和12周胎儿的实际数据的计算,得到两者超声立体视觉图像的非稳定度。结论:由处理之前后的对比图像可清晰地看出利用所提出的非稳定度度量的数据增强算法可以有效改善超声立体视觉的成像质量。 相似文献
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闫龙 《机电产品开发与创新》2010,23(4):32-34
立体视觉是人类的本能之一,研究人类的立体视觉是非常有意义的一件事情。至今为止关于立体视觉在医学机理上尚未形成定论,在相关应用上更是涌现出各种各样的方法。本文主要阐述了对立体视觉形成机理的已有认识、各种技术的发展情况和应用,对现有的立体视觉技术以及相关设备进行分类总结,并分析了相互之间的联系。最后,对立体视觉的发展和应用前景进行展望。 相似文献
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双目立体视觉和三维激光扫描是移动机器人环境探测与建模的常见传感测量方法。为实现两个系统的数据融合应用,必须为二者的测量坐标系建立数学关系,即对其进行传感器之间的位姿联合标定。为此提出了一种基于三维特征点距离匹配的联合标定新方法,设计了一种镂空棋盘格作为标定板。使用双目立体相机提取棋盘格角点三维坐标信息,使用激光测距雷达扫描获取镂空区域中心点三维坐标,最终通过最小化两组特征点的理论与实际测量距离的平方差获取两传感器坐标系之间的旋转矩阵和平移向量。进行的联合标定测量实验结果表明了该方法的准确性和可靠性。 相似文献
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立体视觉中的图像立体匹配方法 总被引:1,自引:0,他引:1
图像立体匹配是立体视觉的核心技术,在三维重建、视觉测量及目标识别等领域中得到了广泛的研究和应用.根据立体匹配技术特点,图像立体匹配可分为三大类:局部立体匹配、全局立体匹配和半全局立体匹配.着重介绍了前两大类中典型的图像立体匹配方法.对各种图像立体匹配方法的匹配算法进行了分析研究,并对图像立体匹配方法的发展提出了一些建议. 相似文献
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分析铁谱技术在机械装备磨损状态检测中发挥了重要作用,但其仅能提供磨粒二维图像,导致磨粒形貌信息不足。为实现磨粒三维形貌的精确重建,联合光度立体视觉和图像校正,为精确重建磨粒的三维形貌,联合光度立体视觉和图像。该方法首先采用大津阈值法由全光源图像识别磨粒与背景区域;然后为消除LED发光强度差异对磨粒形貌重建的影响,结合平面形状和朗伯反射模型确定背景区域的理想成像亮度,并校正各光度图像序列的亮度;最后根据光度立体视觉方法,由校正后光度图像序列重建磨粒的三维形貌。以不同类型的磨粒为测试样本,将所提出的方法的重建结果与激光共聚焦显微镜的测量结果进行对比。结果表明:重建磨粒的形貌参数误差小于15%,表明提出的方法能够精确重建磨粒的三维形貌。 相似文献
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结合透视投影模型、非参数化的光学畸变模型以及光束平差算法,提出并实现了一种标定显微立体视觉系统光路的方法。首先,通过光刻方法制作了用于显微立体视觉系统标定的标定参考物,并利用待标定系统采集标定参考物不同方位的图像。然后,基于非参数化的光学畸变模型,采用样条曲面计算得到显微立体视觉系统的畸变校正场,并结合透视投影模型建立显微立体视觉系统的完整成像模型。最后,利用光束平差算法对所建立的成像模型进行标定计算和优化调整。搭建了显微立体视觉小尺度测量装置,验证了提出的标定方法的可行性。通过标定获得了测量装置两个光路的焦距和相对方位等参数,并借助于高精度四轴位移台对标定结果进行了精度验证。结果表明,采用本文方法标定后位移测量的精度优于1%,能够满足微胀形实验中三维变形测量的要求。该标定方法也可用于其他显微视觉检测领域。 相似文献
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针对线结构激光扫描系统标定成本高,而双目立体视觉测量中立体匹配难的问题,提出了在双目立体视觉的原理上,结合线结构激光扫描的方法实现对被测物体的三维测量。该方法采用张正友相机标定方法对系统进行立体标定;采用BOUGUET’S法对左右相机图像进行立体校正;运用重心法进行激光中心线的精确提取。在图像校正的基础上,可快速实现激光中心线位置的立体匹配;再结合线扫描原理可完成对物体的扫描工作。最后,使用该系统对具有复杂自由曲面的鞋楦进行测量,结果表明:该方法能快速准确地测量出符合要求的三维数据。 相似文献
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The received signal in ultrasonic pulse-echo inspection can be modeled as a convolution between an impulse response and the reflection sequence, which is the impulse characteristic of the inspected object. Deconvolution aims at approximately inverting this process to improve the time resolution so that the overlap between echoes from closely spaced reflectors becomes small. This paper presents a modified minimum entropy blind deconvolution algorithm for deconvolving ultrasonic signals. Enhancement of the resolution is achieved by using the presented method. In addition, the presented approach will, in many cases, lead to a faster computation. A nonlinear function is the key point to the efficiency of the modified blind deconvolution algorithm, which is used to increase the sparsity of the iteration output and to decrease the influence of the added noise by replacing each iteration output by output of the nonlinear function. Simulations showed the efficiency of the modification as compared with minimum entropy deconvolution when deconvolving synthetic ultrasonic signals. Experimental results using real ultrasonic data evaluated further that the exact solution consistently yields good performance. The thickness of a thin steel sample can be calculated by the modified blind deconvolution filter with a reasonable accuracy. 相似文献
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Adaptive filters, with their efficiency and simplicity, have been used successfully in various ultrasonic NDT signal processing contexts. Of these, the adaptive deconvolution with the conventional least-mean-squares (LMS) adaptive filter has improved time resolution. However; the convergence speed of LMS is restricted by the eigenvalue spread of the input correlation matrix. This paper explores the potential of other adaptive algorithms, namely, normalized least-mean-squares (NLMS), recursive least squares (RLS) and QR-decomposition-based RLS (QR-RLS) to handle the deconvolution of ultrasonic NDT signals and compare their performances with that of the conventional LMS algorithm. Furthermore, the mean square error (MSE) behavior in the different adaptive filtering algorithms for ultrasonic NDT signals deconvolution is briefly introduced. Experiments results are explained by graphs and discussed based on the performance criteria. The proposed methods enhanced the resolution quality, offering more alternatives for this application according to specific case requirements. 相似文献
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V. K. Astashev N. A. Andrianov M. P. Kozochkin L. V. Kolik V. L. Krupenin N. V. Solis-Pinargote 《Journal of Machinery Manufacture and Reliability》2009,38(6):566-571
The results of processing various materials with autoresonance ultrasonic turning are presented. After the ultrasonic processing
of metals, nanostructured near-surface layers emerge that are responsible for the macromechanical characteristics of the material.
The developed technology allows for the processing of various hard-to-machine materials with the obtainment of a surface of
heightened geometrical and mechanical properties and with minimum power inputs and material capacity. 相似文献
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对超声波清洗技术从原理、工艺、适用范围等方面进行了分析,比较了超声波清洗与其它清洗方式的效果,给出了轴承套圈超声波清洗的具体工艺参数,阐述了超声波清洗技术的优点及发展前景。 相似文献
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Kyung Cho Kim Hiroaki Fukuhara Hisashi Yamawaki 《Journal of Mechanical Science and Technology》2002,16(12):1627-1632
In this paper, a simplified ultrasonic CT system, which uses the information in three directions, that is, 90°, +45° and —45°
about the inspection plane, is applied to the high strength steel, and the frequency analysis method for enhancing the C scan
or CT image is developed. This frequency analysis method is based on the frequency response property of the material. By comparing
the magnitudes in the frequency domain, the special frequency which shows a significant difference between the welded joint
and base material was found and used to obtain a C scan or CT image. Experimental results for several kinds of specimens,
having a welded joint by electron beam welding, a weld joint by arc welding, on a fatigue crack, showed that the obtained
C scan or CT image has better resolution than the results of previous experiments using the maximum value of the received
waveform. 相似文献
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Kim Geonwoo Hwang Young-In Seo Mu-Kyung Kim Ki-Bok 《Journal of Mechanical Science and Technology》2020,34(8):3155-3164
Journal of Mechanical Science and Technology - In this study, two simple electrical impedance tuning methods derived from Krimholtz, Leedom, and Matthaei (KLM) modeling were proposed for increasing... 相似文献
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基于联邦式的云制造服务架构及云制造联邦执行支撑环境,研究了基于模型驱动的云制造联邦接入技术,包括以扩展UML Profile进行云制造平台的问题域元模型的规范化表示、对象约束语言定义的形式化约束表达以及关系定义语言实现的平台对象模型生成算法。这些技术有利于云制造平台快速、一致地构建联邦式协同环境,避免人工准备协同过程难以保持语义一致性的问题,提高协同准备的效率。 相似文献