Digital Holography with Increased Space-Bandwidth Product
Final Report Abstract
In this project, the calculation of high SBP holograms from several low SBP holograms was demonstrated. A new phase shifting approach was developed, that combines features of temporal and spatial phase shifting. This approach has the technical advantages of a higher energy efficiency of the reference wave and lesser stray light and laser safety issues. Two new approaches were developed for the reconstruction, a projection based approach and an approach that is based on a linear approach. The registration was achieved using a new approach that is based on an analysis of the phases in the spectrum of the measured images. This approach allows the reconstruction of the CCD shift and the phase shift for each recorded hologram without prior knowledge. The model, that the new methods are based on, treats the aliases of the cross terms as independent cross terms, and shows that they have a different phase shift, that depends on the CCD shift of the respective image. It was found that under practical conditions, the registration of the phase shift of the low SBP holograms directly from the measurement is mandatory. Further, it was found, that tilts of the CCD sensor prevent this registration. These findings have the consequence, that the developed approach cannot be used in conjunction with CCD tilts.
Publications
- “Resolution enhancement by time-multiplexed acquisition of sub-pixel shifted images employing a Spatial Light Modulator”, in: International Symposium on Optomechatronic Technologies (ISOT), IEEE (2010), p. 1-6
Alexander Hildebrand, Claas Falldorf, Christoph von Kopylow and Ralf B. Bergmann
- “Resolution enhancement in digital holography by optoelectronic sub-pixel shifting”, in: 10th Euro-American Workshop on Information Optics (WIO), IEEE (2011)
Alexander Hildebrand, Claas Falldorf, Christoph von Kopylow and Ralf B. Bergmann
- “A fast and robust approach to phase shift registration from randomly phase shifted interferograms”, in: SPECKLE 2012: V International Conference on Speckle Metrology. International Society for Optics and Photonics (2012), p. 84130R-84130R-6
Alexander Hildebrand, Claas Falldorf, Christoph von Kopylow and Ralf B. Bergmann
- “Determination of wave fields with high space-bandwidth product by means of sub pixel sampling and irregular phase shifting”, in: 13th Euro-American Workshop on Information Optics (WIO), IEEE (2014)
Colin Dankwart, Claas Falldorf and Ralf B. Bergmann
(See online at https://doi.org/10.1109/WIO.2014.6933303)
