A Rigid Borescopic Fringe Projection System for 3D Measurement of Hard-to-Access Areas and Limited Space – Viboscop

Abstract

The inspection and characterization of machine parts is still subject to research. While optical means of measurement are very promising in respect to speed and precision, they are still not capable of measuring difficult to reach inner geometries. We’ve developed a borescope based fringe projection system that is capable of fast and precise geometry acquisition while the small measurement head is none the less capable of measuring areas with very limited space available. When measuring an object with a conventional fringe projection system it is usually not possible to cover all areas with the desired measurement sensitivity. Depending on the geometry some areas might be measured in a large angle that affects the quality of the acquired data. The measurement head has a diameter of less than a centimeter and the length of the borescope may be adjusted according to the measurement task. It is possible to position the measurement system according to the surface measured. The angle between the area of measurement and the measured objects surface can therefore be optimized. Additionally the measurement head is small enough to be positioned in between parts of an object with a complex geometry e.g. between blades of a blisc (blade integrated disc) While the principles of fringe projection have not to be changed, calibrating the system was a new challenge.