【摘 要】
：
考虑数字相机分辨率的正在不断提高这一现实趋势以及高速动态变形测量中分析多幅图像的普遍需求,快速、高精度数字图像相关算法变得越来越重要.针对数字图像相关方法发展中的
论文部分内容阅读
考虑数字相机分辨率的正在不断提高这一现实趋势以及高速动态变形测量中分析多幅图像的普遍需求,快速、高精度数字图像相关算法变得越来越重要.针对数字图像相关方法发展中的这一迫切需求,本文提出一种无冗余计算的反向配准数字图像相关方法.首先,该方法用无需在每次迭代过程中对Hesssian矩阵进行更新和求逆的反向组合配准策略(Inverse compositional image alignment,ICIA)和Gauss-Newton算法结合来代替经典的基于Newton-Raphson算法的正向配准策略来优化零均值归一化最小平方距离相关函数(zero-mean normalized sum of squared difference,ZNSSD)准确计算亚像素位移;其次,该方法采用改进的可靠性导向初值传递方法自动为每一个计算点提供准确和完整的变形初值估计,有效提高了迭代计算的收敛速度;最后,该方法采用插值系数查找表来避免亚像素灰度插值中的重复计算.通过以上三点创新,该方法能够避免在目前普遍使用的(前向迭代)数字图像相关方法各个计算步骤(初值估计、亚像素位移测量和亚像素插值)中涉及到的大量冗余计算,可在不降低测量精准度的前提下,大幅提高计算效率.本文用计算机模拟散斑图和实际实验图片仔细测试了反向配准数字图像相关方法的测量准确度和计算效率.实验结果显示,本文提出的反向配准数字图像相关方法的位移测量精度与目前广泛使用的基于Newton-Raphson算法的正向配准数字图像相关方法接近,但在同等计算条件下,其计算效率约为后者的3～5倍,有望成为DIC中的标准算法.
其他文献
At room temperature,non-thermal RF plasma treatments,such as O2 plasma,Ar plasma,etc.,are well known techniques to clean surfaces by removing impurities.The tec
Three Ni-based catalysts prepared by different methods were investigated with CO2 reforming of CH4.A special attention was paid to the catalytic stability.The e
Coal pyrolysis to acetylene (C2H2) in thermal plasma provides a highly efficient and cleaner means to make chemicals from coal resources.As the coal particles a
Carbon nanotube supported Ptnanocatalyst was prepared by facile glow discharge plasma reduction operated at room temperature.TEM,XRD and electrochemical measure
TiO2 has been studied in extensive applications such as photocatalysis,photovoltaics,biocompatibility,and sanitary disinfection.Non-thermal plasma (NTP) is high
Due to various benefits such as atomic level thickness control and excellent conformality,atomic layer deposition (ALD) is expected to play an important role in
热障涂层(TBC)由陶瓷层(TC)、热生长氧化层(TGO)和连接陶瓷层与高温合金基底的金属粘结层(BC)组成,被广泛应用于燃气轮机高温透平叶片.在服役工程中热障涂层失效模式主要是界
Nanostructured materials have been an im-portant subject since the late 1980s.There are many methods developed for synthesis of nanomaterials such as ball-milli
In this work,the multi-scale deformation and interfacial mechanical behavior of the carbon nanotube fiber with multi-level structures are investigated by experi
用数字图像相关(DIC)方法测量变形时,一般需要用数字CCD或CMOS相机采集图像并存贮到计算机中处理,最近发现数字相机的温度改变(不管是由于长时间使用自发热引起的还是由于外