Article

Multiwavelength digital holography with autocalibration of phase shifts and artificial wavelengths.

Fraunhofer Institute for Physical Measurement Techniques, Heidenhofstrasse 8, D-79110 Freiburg, Germany.
Applied Optics (impact factor: 1.41). 12/2009; 48(34):H1-8. pp.H1-8
Source: PubMed

ABSTRACT 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.

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Keywords

absolute measurement accuracy
 
algorithm
 
artificial wavelength
 
calibration method
 
efficient method
 
experimental setup
 
generated artificial wavelength
 
lensless holography
 
lensless multiwavelength digital holography
 
measurement accuracy
 
novel implementation
 
one additional image acquisition
 
phase shifts
 
shape measurement
 
simple
 
simple modification
 
steep edges
 
temporal phase shifts
 
wavelength
 

Daniel Carl