【摘要】 混凝土结构的无损检测对于桥梁安全来说意义非凡。无损检测技术的基本目的是在不损伤构件的前提下,检测出物体中的缺陷,并确定其位置、大小和性质。在混凝土无损检测中常用的是超声层析成像代数重建技术(ART)。由于ART算法一般采用直线射线追踪,投影矩阵一经确定不再改变,不仅计算精度低,而且在异常体周边单元出现速度远离真值的现象。本文引入了最短路径(SPT)射线追踪,在每次ART迭代之前,利用SPT射线追踪重新计算投影矩阵,再进迭代计算。计算机仿真结果及混凝土试件实验结果表明:SPT射线追踪与ART相结合的算法具有更好的CT重建效果和消噪能力,并提高了计算的精度和图像重建质量。更多还原

【Abstract】 Non-destructive testing of concrete structures for the bridge safety is significant.The basic purpose of NDT is under the premise that does not damage the components to detect defects in the object and determine its location,the size and nature.The ultrasonic tomography algebraic reconstruction technique(ART) commonly is used in Non-destructive testing of concrete.As a result of ART algorithm is generally used as a straight line ray tracing,if the projection matrix has been determined,it will not to change,thus it not only with low accuracy,but around the unit of abnormal body to which the rate away from the true value.The shortest path(SPT) ray tracing is introduced in each iteration before the ART,SPT is usd to recalculate projection matrix ray tracing,then carry out the iterative calculation.Computer simulation results and the concrete specimens experimental results show that SPT ray tracing combined with the ART algorithm has a better effect of CT reconstruction and denoising capacity,and improve the precision and quality of image reconstruction.更多还原