||The elements of concrete structures suffering from chemical reactions tend to be an expansion phenomenon, which leads to cracks. Non-contact measurement is employed to analysis the relationship between concrete expansion and crack width. This paper deals with semi-automatic crack feature extraction from digital multi-temporal close-range images with non-metric camera and processes the image adjustment with lens distortion parameters. Furthermore, the relationship between image and object space is obtained by 2-D projective transformation to do tilt rectification. Only few roughly manual seed points are required on crotches of crack features. Then, the shape and position may be illustrated with automatic feature extraction in two-dimensional image space. Because manual seed points are not exactly located on the crack features, two methods are proposed to search the geometric crack features, such as crotches. Wavelet transformation, clumpping, thinning and crossing algorithm are processed sequentialy to reach the automatic feature extraciton purpose. Depending on these seed points, crack tracks and edges are determined by the method in this paper. Local image registration is utilized to raise relative accuracy and acquire the expansion of concrete cracks.|
Armin Gruen and Haihong Li; 1997. “Semi-Automatic Linear Feature Extraction by Dynamic Programming and LSB-Snakes”, Photogrammetric Engineering & Remote Sensing Vol. 63,No. 8, August, pp. 985-995.
Chang, Y. L., Li, X., 1994 “Adaptive image region-growing”, IEEE Trans Image Process 3: pp.868-872.
Clive S. Fraser; 1997. ”Digital Camera Self-Calibration”, ISPRS Journal of Photogrammetry & Remote Sensing Vol.52, pp.149-159.
Conzalez, C. R., Richard, E. W., 1993. “Digital Image Processing”, Addison-Wesley Publishing Company.
Deok, J. P., Nam, K. M., Park, R. H., 1995 “Multi-resolution edge detection techniques”, Pattern Recognition, Vol. 28,no. 2, pp.211-229.
Dolar-Mantani, L. M. M., 1983. Undulatory extinction in quartz used for identifying potentially alkali-reactive rocks: Proc. 5th ICAAR, pp. 1-12.
Kraus, k., 1993. PHOTOGRAMMETRY volume 1 Fundamentals and Standard Processes. pp. 188.
LŰ, Y., 1988. Interest Operator and Fast Implementation. International Archives of Photogrammetry and Remote Sensing, Vol.27-II, XVI ISPRS Congress, Kyoto, Japan, pp.491-500.
Moravec, H.P., 1977, Towards Automatic Visual Obstacle Avoidance, International Joint Conference of Artificial Intelligence, Vol.1, Tokyo, pp.584.
Paul M. Dare, Harry B. Hanley, Clive S. Fraser, 2002. “An Operational Application of Automatic Feature Extraction: The Measurement of Cracks in Concrete Structures”, Photogrammetric Record, 17(99): pp.453-464 April.
Roberts, R. A., Mullis, C. T., 1987. Digital Signal Processing. pp. 183.
Wolf, P. R., Dewitt, B. A., 2000. Elements of Photogrammetry with Applications in GIS 3rd edition. pp. 543-548.