Hier finden Sie wissenschaftliche Publikationen aus den Fraunhofer-Instituten.

Digital neutral density filter for moving picture cameras

: Schöberl, M.; Oberdörster, A.; Fößel, S.; Bloss, H.; Kaup, A.


Bouman, C.A. ; Society for Imaging Science and Technology -IS&T-; Society of Photo-Optical Instrumentation Engineers -SPIE-, Bellingham/Wash.:
Computational imaging VIII : 18 - 19 January 2010, San Jose, California, United States; proceedings IS&T/SPIE electronic imaging, science and technology
Bellingham, WA: SPIE, 2010 (Proceedings of SPIE 7533)
ISBN: 978-0-8194-7926-6
Paper 75330L
Conference "Computational Imaging" <8, 2010, San Jose/Calif.>
Conference Paper
Fraunhofer IIS ()

Typical image sensors in digital cameras have a fixed sensitivity, and the amount of captured light energy is often controlled by adjusting exposure time and lens aperture. For high end motion imaging these settings are not available as they are used to set motion blur and depth of field, respectively. In many cases a proper exposure is achieved with additional optical filtering, using so called "neutral density" (ND) filters. We propose a digital equivalent of a neutral density filter, which can replace the handling of optical filters for camera systems. It consists of an adjusted sensor readout and in-camera processing of images. Instead of a single long exposure we capture N short exposures. These images are then combined by averaging. The short exposures reduce the sensitivity by a factor of N, while averaging reconstructs motion blur. In addition we also achieve a reduction of both dynamic and fixed pattern noise which leads to an overall increase in dynamic range. The digital ND filter can be used with regular image sensors and does not require hardware modifications.