A DIGITALIZATION OF HAMMER TESTING IN TUNNEL INSPECTION FROM MOVIES

Abstract

 This paper presents a digitalization of hammer testing in tunnel inspection from movies in which the activity is recorded. The proposed method first extracts keyframe images at the moment of hammer-hit on surface through the acoustic analysis of hammering sound in the input movies. For each keyframe, our method computes the hammered position, and converts it to the position in the coordinate system of a base image known as labframe image using homography transformation of the two images. The result is obtained by the integration of hammered positions, associated times and sounds, and it makes possible additional analyses including distribution analysis and evidence of judgement. This paper also demonstrates applications to a skill evaluation of tunnel inspectors.