6 Surface characterisation based on optical metrology

For the complex task of measuring the insides of a cylinder liner using optical sensors, new methods had to be developed. Since optical sensors for areal measurements, such as white light interferometers and confocal microscopes, require too much space and have a limited measuring range, a confocal chromatic white light sensor was used. The chromatic sensor is a point sensor that allows for precise positioning inside of cylinder liners, as only a small part of the apparatus has to be brought inside the cylinder while the signal is transported to the controller by optical fibre.