Image recognition through turbulent media by MEMS micromirror-based Adaptive Optics
7 November 2006 - 9 November 2006
Austria
The technology of Adaptive Optics (AO) for image recognition through turbulent media originally evolved from astronomy for more than 30 years and has been employed at ground-based telescopes in order to compensate for atmospheric turbulences for an enhanced optical imaging. Besides the actual image recording unit an AO system essentially comprises a wavefront sensor and a wavefront corrector for measurement and compensation of the occuring optical wavefront aberration across the entrance pupil aiming at a pure diffraction-limited imaging in the ideal case. The key component is formed by the actual corrector device, where mostly a deformable mirror is used for a dynamic generation of appropriate surface profiles in order to cancel the optical path differences.
So far, existing systems mainly from astronomy are comparatively heavy, bulky and expansive, which actually is the main impediment for a wider dissimination and commercial exploitation of AO technologies in other application areas. However, nowadays the methods of micromachining and semiconductor fabrication have opened up new perspectives especially in terms of large-scale intergration of micromechanical MEMS mirror arrays on top of integrated address circuits enabling an unprecedented spatial resolution and precision together with a significant device miniaturization and a cost-effective fabrication.The Fraunhofer IPMS therefore has developed a fine segmented 240 x 200 micro mirror array for high-resolution optical wavefront control including also the complete driver hardware and software. Furthermore, for presentation purposes as well as for a more quantitative analysis a compact and flexible AO demonstration system has been implemented, where the obtainable imaging enhancement for various static or dynamic wavefront distortions can be impressively demonstrated.
Possible applications are image and object recognition in machine vision, wavefront correction for optical imaging enhancement e.g. in ophthalmology, microscopy, and astronomy as well as spatial and temporal laser beam and laser pulse shaping. For those purposes MEMS micromirrors offer further advantages in terms of fast mechanical response times, high spectral bandwidth from IR to DUV, and polarization insensitivity.At the VISION 2006 in Stuttgart, Hall 2.0 Stand 2.0.141 Fraunhofer IPMS will present a demonstrator system.
So far, existing systems mainly from astronomy are comparatively heavy, bulky and expansive, which actually is the main impediment for a wider dissimination and commercial exploitation of AO technologies in other application areas. However, nowadays the methods of micromachining and semiconductor fabrication have opened up new perspectives especially in terms of large-scale intergration of micromechanical MEMS mirror arrays on top of integrated address circuits enabling an unprecedented spatial resolution and precision together with a significant device miniaturization and a cost-effective fabrication.The Fraunhofer IPMS therefore has developed a fine segmented 240 x 200 micro mirror array for high-resolution optical wavefront control including also the complete driver hardware and software. Furthermore, for presentation purposes as well as for a more quantitative analysis a compact and flexible AO demonstration system has been implemented, where the obtainable imaging enhancement for various static or dynamic wavefront distortions can be impressively demonstrated.
Possible applications are image and object recognition in machine vision, wavefront correction for optical imaging enhancement e.g. in ophthalmology, microscopy, and astronomy as well as spatial and temporal laser beam and laser pulse shaping. For those purposes MEMS micromirrors offer further advantages in terms of fast mechanical response times, high spectral bandwidth from IR to DUV, and polarization insensitivity.At the VISION 2006 in Stuttgart, Hall 2.0 Stand 2.0.141 Fraunhofer IPMS will present a demonstrator system.