Novel Non-mechanical Liquid Crystal based Foveated Imaging System

A novel foveated imaging technology is proposed, suitable for integration into an urban surveillance system. The proposed technology has no moving parts has low power requirements and requires a single imaging camera. The technology exploits the beam steering capabilities of liquid crystal polarization gratings (LCPGs) which diffract light only into the m=±1 orders according to the handedness of incident circular polarization which is controlled by switchable halfwave plates. The LCPGs steer the high field angles into the axial direction of a lens train where a high resolution image is produced. Field angles simultaneously steered into off-axis directions produce a blurred image region due to lens aberrations. A second LCPG stack and lenses re-image and re-steer the object field to the image plane reversing grating dispersion and image shift. The result is a static image field with a moveable foveated region. The technology is suitable for wide angle imaging as the lens aberrations do not have to be corrected for high angles. The system is integrated with a hemispherical mirror to capture a 360°X20° field of regard. A 10x foveated region zoom is provided by additional small diameter axial lenses. Polarization independent operation is possible using a two arm system.