数字聚焦超声反射CT成像初步研究

对于单元发，阵接收的模型，采用反射回波的包络作为投影，按滤波后投影算法（ＦＢＰ法）进行重建，得到物体内某一截面的重建像，然后调整接收阵的位置，获取多层截面的投影并重建成像，运用体绘制法（ＶｏｌｕｍｅＲｅｎｄｅｒｉｎｇＩｍａｇｉｎｇ）绘制了三维像，图像效果不好，分辨率不高，针对这一问题，文中应用了电子延迟方法处理接收信号，即对接收阵各阵元接收到的回波号依照散射点相对接收中阵的空间位置关系进行一定时间

Initial research of digital focusing method in ultrasonic reflection CT imaging

For the model of unit transmit array receive, we adopt overlap of echo pulse as projection and reconstruct it by the way of FBP (filter back projection) algorithm. Thus we get the reconstructed image of a section of the subject. Then by adjusting the position of the receiving array we get the projection of multi section and reconstruct it, using Volume Rendering Imaging method we get three dimension image, the quality of this image is not good and its resolution is low. In order to solve the problem this paper apply electronic delay technique to deal with receiving signal, namely echo pulse which every array unit received towards the scatter point delay for some time according to relative position between array unit and scatter point. Using this signal processing method to repeat the word what had discussed previously, the result is of high resolution and good quality contrast with previous one.