DEVELOPMENT OF REAL-TIME INSPECTION SYSTEM FOR SUPPORTING CRACK DETECTION OF CONCRETE SURFACEAND ITS PRACTICALITY

Abstract

 For better supporting concrete surface crack inspection, this paper presents a real-time visibility evaluation system (VIS system) with video camera for supporting fine crack detection of concrete surface and its practicality. In this system, the power spectra for the fluctuation of digital number values (i.e., spatial frequency components) in each pixel of the animation-like Feature Composite moving image (FC image) inducing visual illusion can be delineated on "Visibility Evaluation image (VE image)." Through the site inspection for various kinds of concrete surfaces of tunnel lining, box culvert and concrete slab bridge, the results can be summarized as follows: i) The simultaneousdisplayingof FC and VE image corresponding to negative and positive moving image is effective in detecting the crack of "0.1-0.2mm" in width, even from the place 10m away from the concrete surface, and ii) Real-time processing of magnification and reduction for FC and VE image contribute to prevent the inspectors overlooking those fine cracks from workbench of vehicle forhigh lift work.