modal identification of structures via video processing and blind source separation

Techniques of health monitoring and assessment of engineering structures by vibrational data are one of the most common methods for identifying structural damages, in which have surveyed since three decades till now. the basic idea for damage detection based on structural dynamic among studies is variations in physical properties such as mass, damping, and stiffness due to damages that cause the modal properties, that is, natural frequencies, modal ratios and mode shapes would be detectable. thus, variation in modal parameters of a structure implies the variation of structural health condition, i.e. damage. therefore, experimental measurement and determination of dynamic behaviour of structureis important.