The paper presents an application of the wavelet transform for damage detection based on optical measurements. A number of important issues that need to be considered when image sequences are used for vibration analysis are discussed. These include: correspondence of image features from image to image, image calibration and spatial resolution. The principles of image edge detection are discussed and a comparison between the wavelet approach and the classical method is presented. A novel damage detection method based on optically measured mode-shape data is proposed. The method is illustrated using a simple cantilever beam experiment. The major advantage of the method is the significantly increased number of discrete points used to describe mode shapes. This is in contrast to classical techniques where in practice a small number of measurement points are obtained from a limited number of sensors.
Dynamic testing agency modal testing primer (1993). Primer on best practice in dynamic testing. London: Chameleon Press Ltd.
2.
Maia, N.M.M., Silva e, J.M.M., He, J., Lieven, N.A.J., Lin, R.M., Skingle, G.W., To, W.-M. and Urgueira, A.P.V. (1997). In N.M.M. Mai and J.M.M. Silva e (Eds.), Theoretical and experimental modal analysis. England: Research Studies Press Ltd, John-Wiley & Sons Inv.
3.
Ewins, D.J. (2000). Modal testing: theory, practice and application. (2nd ed.) England: Research Studies Press Ltd. September.
4.
Patsias, S. (November 2000). Extraction of dynamic characteristics from vibrating structures using image sequences. PhD Thesis, University of Sheffield, United Kingdom.
5.
Walton, J.S., Nalodka, E.C., Adam, W.R., Darling, R.S., Fung, S. and Gleason, J.T. (1989). Over-the-road video based measurements of suspension kinematics. SAE Technical Paper Series, 801143. Proceedings of the 1989 Noise and Vibration Conference (pp.175-183). Traverse City, Michigan, May 16-18.
6.
Cafforio, C. and Rocca, F. (1976). Methods for measuring small displacements of television images. IEEE Trans. On Information Theory, IT-22(5), 573-579.
7.
Houkes, Z. (1983). Motion parameter estimation in TV-pictures, In: T.S. Huang, (Ed.), Nato advanced study institute on image sequence and dynamic scene analysis. Image sequence processing and dynamic scene analysis (pp. 249-263). Berlin: Springer.
8.
Lenz, R. and Gerhard, A. (1983). Image sequence coding using scene analysis and spatio-temporal interpolation. In T.S. Huang, (Ed.), Nato advanced study institute on image sequence and dynamic scene analysis. Image sequence processing and dynamic scene analysis (pp. 264-274). Springer: Berlin.
9.
Kuttenkeuler, J. (2000). Optical measurements of flutter mode shapes. J. Aircraft, 37(5), 846-849.
10.
Patsias, S., Staszewski, W.J. and Tomlinson, G.R. (1997). Wavelet based edge detection for structural dynamics. CD-ROM Proceedings of the Symposium on Time-Frequency and Wavelet Analysis at the 16th Biennial Conference on Mechanical Vibration and Noise. ASME Design Engineering Conferences. Sacramento, California, Paper No. DETC97/VIN-4138.
11.
Zhong, S. (September 1990). Edge representation from wavelet transform maxima. Ph.D. Thesis, New York University.
12.
Pattern Analysis and Machine Intelligence, (July 1992), 14(7), 710-732.
13.
Marr, D. and Hildreth, E. (1980). Theory of edge detection. Proc. R. Soc. London, B207 (pp. 187-217).
14.
Canny, J. (November 1986). A computational approach to edge detection. IEEE Trans. on Pattern Analysis and Machine Intelligence, PAMI-8(6), 679-698.
15.
Mallat, S. and Zhong S.Characterization of signals from multiscale edges. IEEE Transactions on.
16.
Jain, A.K. (1989). Fundamentals of digital image processing. USA: Prentice-Hall, Inc.
17.
Nair, D., Mitiche, A. and Aggarwal, J.K. (1995). On comparing the performance of object recognition systems. Intern. Conference on Image Processing.
18.
Mallat, S. and Zhong, S. (1992). Wavelet transform maxima and multiscale edges. In M.B. Ruskai, G.M. Beylkin, R. Coifman, I. Daubechies, S. Mallat, Y. Meyer and L. Raphael (Eds.), Wavelets and their applications (pp. 67-104). Jones and Bartlett.
19.
Hummel, R. and Moniot, R. (December 1989). Reconstruction from zero-crossings in scale-space. IEEE Trans. on Acoustic Speech and Signal Processing, 37(12), 2111-2130.
20.
Mallat, S. (July 1991). Zero-crossings of a wavelet transform. IEEE Trans. on Informations Theory, 37(4), 1019-1033.
21.
Mallat, S.G. (July 1989). A theory for multiresolution signal decomposition: the wavelet representation. IEEE Trans. on Pattern Analysis and Machine Intelligence, 11(7), 674-693.
22.
Mallat, S.G. (July 1989). Multifrequency channel decompositions of images and wavelet models. IEEE Trans. on Acoustics, Speech, and Signal Processing, 37(12), 2091-2110.
23.
Mallat, S. and Zhong, S. (1991). Compact image coding from edges with wavelets. Proceedings of the International Conference on Acoust. Speech and Signal Processing (pp. 2745-2748).
24.
Image of a bridge. (2002) Downloaded from internet site: www.freeimages.co.uk, Hypertext link: www.btinternet.com/fireballx5/buildings/structures/pics/bridge04090075.jpg, 1st, February.
25.
Mathworks Inc. (1997). Wavelet Toolbox for used with Matlab V1., January.
26.
Wave2 Downloaded from Internet ftp site, ftp://cs.nyu.edu/oub/wave/software.
27.
Mathworks Inc. (1998). Image Processing Toolbox for use with Matlab V2.1, January.
28.
Doebling, S.W., Farrar, C.R., Prime, M.B. and Shevitz, D.W. (1996). Damage identification and health monitoring of structural and mechanical systems from changes in their vibration characteristics: A literature review. Report LA-13070-MS, UC-900, Los Alamos National Laboratory, New Mexico 87545, USA. May.
29.
Pandey, A.K., Biswas, M. and Samman, M.M. (1991). Damage detection from changes in curvature mode shapes. Journal of Sound and Vibration, SIAM, 145(2), 321-332.
30.
Worden, K. (1990). Data processing and experiment design for the restoring force surface method. part 1: integration and differentiation of measured time data. Mechanical Systems and Signal Processing, 4(4), 295-319.
31.
Sony Corporation. (1996). Operating Instructions - Video Camera Recorder video Hi8 CCD-TR760E/TR810E Hi8, France.
32.
Eastman Kodak Company Kodak MotionCorder Analyzer. (1996). User’s Manual Model 1000, San Diego, California.
33.
Lee, C.-H. and Joshi, A. (1993). Correspondence problem in image sequence analysis. Pattern Recognition, 26(1), 47-61.
34.
Tsai, R.Y. (August 1987). A versatile camera calibration technique for high-accuracy 3D machine vision metrology using off-the-shelf TV cameras and lenses. IEEE Journal of Robotics and Automation, RA-3(4), 323-344.
35.
Weng, J., Cohen, P. and Herniou, M. (October 1992). Camera calibration with distortion models and accuracy evaluation. IEEE Trans. on Pattern Analysis and Machine Intelligence, 14(10), 965-980.
36.
Chapra, S.C. and Canale, R.P. (1998). Numerical methods for engineers - with programming and software applications. Singapore: WCB/McGraw-Hill.
37.
Mathworks Inc. (1999). Matlab Function Reference (Volume1: Reference), version 5, June.
38.
Chance, J.E. (1996). Structural fault detection employing linear and nonlinear dynamic characteristics. PhD Thesis, School of Engineering, University of Manchester.
39.
Krawczuk, M. and Ostachowicz, W.M. (1992). Parametric vibrations of a beam with crack. Archives of Applied Mechanics, 62, 463-473.
40.
Astrom, K. and Heyden, A. (2001). Stochastic modelling and analysis of image acquisition and sub-pixel edge detection. Downloaded from internet site http://citeseer.nj.nec.com/2563.html, September.
