Optical properties of rigid borescopes for measurement purposes under gravitational influences

While rigid borescopes are widely used for the inspection of industrial machinery, there are not many applications where borescope are used to acquire 3D shape information. When using borescopes, bending due to gravitation has multiple effects on the images acquired: The tip will be displaced and rotated distortion will alter the images. This article discusses the use of a borescope for image projection of a compact fringe projection system and the effects of gravitation on the borescope. The bending and distortion was simulated, measured and quantified. Additional means of compensation will be presented.