Immersion ultrasonic reflection tomography by annular array system

Ultrasonic reflection tomography has been proposed for tumor detection in medical care, multiphase flow imaging and material flaw detection in industrial processing. It is a better way than transmission tomography to reconstruct the target shape when the target or the inner component of the target would bring about severe attenuation for ultrasonic propagation. This paper provides the simulation and experimental results of immersion ultrasonic reflection tomography through ellipse algorithm. By reconstruct a series of priori circle targets, the influences of different target locations, different data quantities and different target sizes on the reconstruction image qualities are discussed while the interaction relationships between the 3 influencing factors and detection sensitizing zone of the annular array system are also demonstrated. From the simulation results, annular array system with 80 transducers that is shown in this paper could attain the detection resolution less than 500 μm. An immersion annular array with 16 elements is proposed in this experiment and the ultrasonic transducers which are ring arranged are served as both transmitters and receivers in order to acquire all the data of the sample from 360 degree in the imaginary plane of the ultrasonic beams. The target measured by the real system is a 7 mm radius ceramic sphere, demonstrating the image reconstruction ability with limited data by ellipse algorithm.