针对超声波在混凝土检测中出现的高衰减、高散射、结构噪声大、缺陷信号难于识别和提取的问题，采用合成孔径聚焦成像方法对信号进行处理，提高了成像的分辨率和信噪比。用超声波仿真软件WAVE 3000建立混凝土数值模型，模拟了超声波在混凝土中的传播过程并进行成像：搭建试验系统开展了混凝土超声波检测试验并进行了成像。成像结果表明：该方法可以使混凝土异常体处超声波的能量增强，结构噪声信号的能量减弱，有效提高了缺陷信号的信噪比和分辨率，为混凝土的超声检测提供了一定的参考价值。

Aiming to solve the problems that the ultrasonic signal is characteristic of high attenuation,high scattering and high structural noise, and the flaw signal is hard to obtain and hard to be identified when detecting concrete with ultrasonic testing,this paper presents a synthesis aperture focusing technique(SAFT) to process signal aiming at enhancing the resolution ratio and SNR of the imaging. Firstly,a numerical analysis software WAVE 3000 is employed to build a three-dimensional concrete model which is used for simulating the ultrasonic propagation process inside the concrete. The experimental research is then developed on the system which is set on a large size concrete block samples. The imaging results show that the algorithm can enhance the power of ultrasonic echo signal around the defects and weaken the power of noise signal,which improves the signal SNR of the defect and shows the actual position of the defects,providing reference for concrete testing with ultrasonic.