Design of an expert measurement system for close-range photogrammetric applications

Abstract

Digital photogrammetric systems have been used to solve various measurement problems in industrial applications for many years. Industrial line-scan video cameras have been widely used in these systems and in machine vision applications. This paper addresses the use of a digital photogrammetric expert measurement system for deformation measurements on the surface of concrete materials. The system consists of two industrial cameras having fixed-focus lenses. Because the accuracy of the photogrammetrically derived object data mostly depends on the camera calibration, the system had to be calibrated first. A 3-D wooden object was specially designed and constructed for that purpose. A measurement process of 17 steps was carried out to determine the displacements on the surface of the samples. Linear variable differential transducers were also used to measure the deformations in a conventional way. Data obtained from the two sets of measurements confirmed the system's reliability and allowed us to monitor surface behavior of the concrete samples under loading. (C) 2006 Society of Photo-Optical Instrumentation Engineers.