将广泛应用于雷达系统的合成孔径技术引入超声内窥成像系统, 提出一种基于单换能器探头的超声内窥镜合成孔径成像方法。利用单换能器探头的旋转效应, 在旋转的不同时刻与位置发射并接收超声回波, 等效合成较大的超声发射孔径, 以增强超声图像的信噪比与分辨率。分析了单探头合成孔径技术的原理与合成方法, 并在此基础上根据超声回波的编码与线性调频特性, 完成纵向与横向的脉冲压缩。最后采用中心频率为8 MHz的换能器对猪皮样本进行探测, 可分辨出尺寸为0.8 mm×2 mm的目标, 系统的信噪比提升了9.38 dB。

Synthetic aperture focusing, widely used in radar system, is introduced into endoscopic ultrasound imaging system in this paper. Based on the features of synthetic aperture focusing (SAF), a method of synthetic aperture imaging for ultrasonic endoscope is presented, using the rotation effect of a probe with single transducer, transmitting and receiving the echoes at different time and different locations during the rotation, synthesizing a large transmitting aperture equivalently to enhance the signal to noise ratio and the resolution of the ultrasonic images. The principle of synthetic aperture technique was analyzed, which is used for endoscopic ultrasound imaging with single transducer probe, and then the longitudinal and lateral compression were implemented according to the coded and linear frequency modulated characteristics of the echoes. Finally, an experiment was completed, using a transducer, with the center frequency of 8 MHz, to detect a pigskin sample, the target with the size of 0.8 mm×2 mm could be identified, and the signal to noise ratio had an improvement of 9.38 dB.