Obtaining Method of Hammering Sound Component for Automatic Hammering Inspection in Noise Environment

Abstract

In this study, we considered a method to extract a hammering sound in noise environment by removing the noise component using noise transfer function for carrying out correct inspection of the target construction. In the first experiment, hammering test was performed using two tiles (defective and normal tiles) with or without loud white noise from a speaker. Through the proposed method using two microphones (single response and reference microphones), the hammering sound could be extracted well as the sound without noise. Subsequently, another hammering test was carried out when a drone was operated as an instance of the driving noise. However, the method using two microphones could not extract the hammering sound accurately. Then, the number of the reference microphone was increased from one to four to catch the generated noise of each rotating blade. As the result, the hammering sound difference between normal and defective tiles could be grasped better.