TIME TRANSFORMATION METHOD FOR PULSE THERMOGRAPHY

摘要

Pulse thermography is a method for an inspection of near surface defects. The method is based on heating a tested object with an excitation source (e.g. flash lamp, halogen lamp, laser, microwave) by one pulse. A temperature response is than recorded by a thermographic camera. A result of an evaluation are indications of the defects. The indications are however usually not significant enough or not visible at all without an application of a special data processing methods. A complexity of the evaluation thus often limits a usability of the pulse thermography in industrial applications. The results are often in a form of a sequence composed from many images (typically more than 1000), which should be inspected manually by an operator. We propose and describe a technique, which allows to compress the results to a one image only. This makes an evaluation very fast and very usable for an industrial use. This technique is also suitable for an estimation of depths of the inspected defects. Principles of the proposed evaluation method are described and evaluation results of a steel sample inspection are demonstrated in this contribution. Advantages and disadvantages of the technique are discussed.