Simultaneous Detection of Multiple Reflecting Planes in Concrete Using Ultrasonic Sensor

Abstract

In conventional inspection methods using ultrasonic sensors, the detection was performed by viewing the sensor's output with bare eyes, hence these methods had a low reliability. Also, the conventional methods often failed to detect multiple numbers of reflecting planes (such as cracks) which reside close to each other in the direction of depth. This is because the reflected waves from these planes are often overlapped, adding to that the reflected signal has a spindle oscillatory shape.The present paper contemplates a method to simultaneously detect multiple numbers of reflecting planes using an ultrasonic sensor. Concretely, the sensor output is modeled based on the signal propagation model and a pattern matching technique is used to measure the propagation times of the reflected waves. Furthermore, an optimization method is developed to reduce the computation time significantly. Finally, experiments are conducted to verify the effectiveness of the proposed method.