Development of Reference Specimen in Thermography for NDT

This paper proposes the reference specimen for lock-in photo-infrared thermography. Basically, thermography depends on environmental disturbances, which is related to the defect detection ability of thermography system in non-destructive testing. Reference specimen can be useful in evaluating the detection capacity and the detection range of a defect under a given environmental condition. The proposed reference specimen can be supply the defect size, location and depth by the shearing phase technique and the depth inversion technique. The defect information can be effectively acquired with the well-designed reference specimen. We hope that a reference specimen will improve the reliability of thermography in nondestructive testing.