Fig. 9From: Depth estimation of surface-opening crack in concrete beams using impact-echo and non-contact video-based methodsView of non-contact video-based test result showing strain map of different beams: (a) 12-1# beam; (b) 12-2# beam; (c) 12-3# beam; (d) 16-1# beam; (e) 16-2# beam; (f) 16-3# beamBack to article page