A sparse approximation method for Ultrasonic Monitoring the degradation of adhesive joints

In this paper we propose to apply a sparse approximation method, utilizing a small dictionary, just for signals measured before the degradation started. Then, we update the obtained atoms in order to find approximations for signals acquired after the degradation started. Our atom modification procedure is based on a physical model describing only the changes which occurred during the degradation period. The effectiveness of the proposed method is demonstrated through simulations and experiments involving environmentally degraded samples.