@inproceedings{PulwerSteglichVillringeretal.2016, author = {Pulwer, Silvio and Steglich, Patrick and Villringer, Claus and Bauer, Joachim and Burger, Martin and Franz, M. and Grieshober, K. and Wirth, F. and Blondeau, J. and Rautenberg, J. and Mouti, S. and Schrader, Sigurd}, title = {Triangulation-based 3D surveying borescope}, publisher = {SPIE}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-15307}, pages = {51 -- 56}, year = {2016}, abstract = {In this work, a measurement concept based on triangulation was developed for borescopic 3D-surveying of surface defects. The integration of such measurement system into a borescope environment requires excellent space utilization. The triangulation angle, the projected pattern, the numerical apertures of the optical system, and the viewing angle were calculated using partial coherence imaging and geometric optical raytracing methods. Additionally, optical aberrations and defocus were considered by the integration of Zernike polynomial coefficients. The measurement system is able to measure objects with a size of 50 μm in all dimensions with an accuracy of ± 5 μm. To manage the issue of a low depth of field while using an optical high resolution system, a wavelength dependent aperture was integrated. Thereby, we are able to control depth of field and resolution of the optical system and can use the borescope in measurement mode with high resolution and low depth of field or in inspection mode with low resolution and higher depth of field. First measurements of a demonstrator system are in good agreement with our simulations.}, language = {en} } @inproceedings{PulwerJahnsVillringeretal.2020, author = {Pulwer, Silvio and Jahns, Daniel and Villringer, Claus and Schrader, Sigurd}, title = {Dynamic pattern generation by singlemode fibers for endoscopic 3D measurement systems}, publisher = {SPIE}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-15364}, year = {2020}, abstract = {This work presents experimental and simulation results of a 3D measurement concept based on fiber-optic interference pattern generation. A demonstrator system which is able to adjust different optical and mechanical parameters is described. The results of parameter variation studies are discussed along with possible applications in the field of micro-optical 3D measurement systems like endoscopes. The experiments were prepared with different structures with various scattering properties. To implement that approach into a micro-optical 3D measurement system, the combination of distance variation between the fibers and a controlled phase shift introduced by a retarder can be used to design the system versatile.}, language = {en} } @inproceedings{GilaniVillringerZhangetal.2018, author = {Gilani, Taravat Saeb and Villringer, Claus and Zhang, Edward and Gundlach, H. and Buchmann, Jens and Schrader, Sigurd and Laufer, Jan}, title = {Parallelised photoacoustic signal acquisition using a Fabry-Perot sensor and a camera-based interrogation scheme}, publisher = {SPIE}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-15335}, pages = {217 -- 222}, year = {2018}, abstract = {Tomographic photoacoustic (PA) images acquired using a Fabry-Perot (FP) based scanner offer high resolution and image fidelity but can result in long acquisition times due to the need for raster scanning. To reduce the acquisition times, a parallelised camera-based PA signal detection scheme is developed. The scheme is based on using a sCMOScamera and FPI sensors with high homogeneity of optical thickness. PA signals were acquired using the camera-based setup and the signal to noise ratio (SNR) was measured. A comparison of the SNR of PA signal detected using 1) a photodiode in a conventional raster scanning detection scheme and 2) a sCMOS camera in parallelised detection scheme is made. The results show that the parallelised interrogation scheme has the potential to provide high speed PA imaging.}, language = {en} }