When three-dimensional optical topometry of technical surfaces is performed, one major problem is that often the local reflectance of the object’s surface varies within a wide range. This leads to overexposed and underexposed areas on the detector, where no measurements can be made. To overcome this problem, we have developed a method that extends the dynamic range of an imaging system. As an example we implemented this method to a measurement system that is based on fringe projection with a data projector and a color CCD camera. By projection of quasi-monochromatic fringes a different dynamic range in each of the three color channels of the camera is achieved. Hence the overall dynamic range of the system is increased by a factor larger than 5.
© 2002 Optical Society of America
(110.0110) Imaging systems : Imaging systems
(120.0120) Instrumentation, measurement, and metrology : Instrumentation, measurement, and metrology
(120.6650) Instrumentation, measurement, and metrology : Surface measurements, figure
(150.6910) Machine vision : Three-dimensional sensing
Klaus-Peter Proll, Jean-Marc Nivet, Christoph Voland, and Hans J. Tiziani, "Enhancement of the Dynamic Range of the Detected Intensity in an Optical Measurement System by a Three-Channel Technique," Appl. Opt. 41, 130-135 (2002)