Non-contact measurement of angle of view between the inspected surface and the thermal imager

•A method of measuring the angle of view was proposed.•The proposed method does not need contact with the inspected object.•The proposed method employs laser distance meters, commonly available in the market.•The experimental evaluation led to estimations with acceptable errors.

The angle of view between inspected object and thermal imager influences the values of temperature measured by infrared thermography. This happens because the emissivity depends on the angle of radiation, and because the apparent temperature measured is influenced by that angle of view combined to thermal imager’s field of view. Therefore, it is necessary to know the angle of view during thermographic inspection, which is generally not feasible due to safety reasons. This paper develops a method of measuring the angle of view with no contact with the inspected object, by employing laser distance meters, commonly available in the market.