Abstract In this study, infrared thermography measurement technique has been used to defect detection of composite materials which is widely used in aerospace and wind turbine blades. To increase the defect detection rate, the related experiment used the lock-in IR-thermography method. Unlike the existing reflection method, transmission method that halogen lamp is located behind the specimen has been used to defect detection. The results show that the possibility of detecting defects gets higher than using the transmission method. Infrared thermography images show that all detection of composite material specimen is detected through overall section From 50 mHz to 400 mHz
