Background thermal compensation by filtering (BTCF) for infrared thermography evaluation

A new contrast enhancement technique is presented for application in active thermography inspection, based on a decimated version of median filtering to decouple the background thermal information from defective areas, without depending on any heat propagation model or the a priori selection of a healthy region. Results over inspected carbon fiber reinforced plastic (CFRP) slabs show that BTCF can reduce in 70% the residuary non-uniformity heating, and after truncation of negative contrast values, it can be obtained an improvement up to 11dB in SNR with respect to original sequences.