Multiwavelength digital holography with autocalibration of phase shifts and artificial wavelengths.
A novel implementation of lensless multiwavelength digital holography with autocalibration of temporal phase shifts and artificial wavelength is presented. The algorithm we used to calculate the phase shifts was previously proposed [Opt. Lett.29 183 (2004)] and, to our knowledge, is now used for the first time in lensless holography. Because precise knowledge of the generated artificial wavelength is crucial for absolute measurement accuracy, a simple and efficient method to determine the artificial wavelength directly is presented. The calibration method is based on a simple modification of the experimental setup and needs just one additional image acquisition per wavelength. The results of shape measurement of a metallic test object with a rough surface and steep edges are shown and the measurement accuracy is discussed.
Carl
Daniel
D
Fraunhofer Institute for Physical Measurement Techniques, Heidenhofstrasse 8, D-79110 Freiburg, Germany. daniel.carl@ipm.fraunhofer.de
Fratz
Markus
M
Pfeifer
Marcel
M
Giel
Dominik M
DM
Höfler
Heinrich
H