Field of the Invention
The present invention relates to a device for the contactless and non-destructive testing of a surface by measuring its infrared radiation.
Description of Related Art
The contactless testing of surfaces based on the generation and measurement of transient periodic heating and cooling processes uses an excitation source for heating the surface to be tested as well as an infrared detector which measures the infrared radiation from the heated surface. This method is called photothermy if electromagnetic radiation in the ultraviolet, optical or infrared range is used for excitation.
Such a device is described in US 2013/0037720 using one or more incoherent electromagnetic radiation sources, a detector providing and arrange on an detection axis and comprising a measuring area a testing area defining an area to be measured of the test surface and an imaging device arranged on the detection axis for mapping the testing area onto the measuring area of the detector. The radiation sources are adapted to generate a pulse like or intensity modulated excitation radiation, e.g. flash lights directed onto the surface to be tested in the testing area. The device according to US 2013/0037720 uses e.g. flash lamps allowing to provide a measurement to evaluate the exact thickness of a surface coating having a value between several micrometers and up to 0.1 millimeter.