Implementation of a fast and low cost IR-NDT technique by means of a Square Pulse Modulated Lock-In Thermography
- Authors: Pitarresi, G
- Publication year: 2012
- Type: eedings
- Key words: Infrared Thermography, NDT, Lock In Thermograpghy, Glass Fibre Reinforced
- OA Link: http://hdl.handle.net/10447/64846
Abstract
This work describes the development of an IR-NDT procedure based on a lock-in signal treatment in the frequency domain to obtain phase-contrast defect signatures. Heat stimulation is obtained by periodically shattering a common low-power halogen lamp. The delivered heat is then modulated as a train of square waves with multi-frequency harmonic content. The proposed lock-in algorithm is able to selectively retrieve phase and amplitude information at various frequencies of the acquired temperature, acting also as a narrow band filter to improve defect-signature to noise ratio. The procedure is implemented and evaluated by means of low cost IR equipment to investigate artificially defected thick Glass Reinforced Plastic (GRP) panels.