A novel electro-optic modulator system for the production of dynamic images from Giga-pixel computer generated holograms. Maurice Stanley*, Pat B. Conway, Stuart Coomber, J. Cliff Jones, Dave C. Scattergood, Chris W. Slinger, Bob W. Bannister, Carl V. Browna, William A. Crosslandb, Adrian R. L. Travis". DERA Malvern, Malvem, Worcs. WR14 3P5, UK. a Dept of Engineering, Oxford University, Oxford, UK. b Dept of Engineering, Cambridge University, Cambridge, UK. ABSTRACT Holographic techniques offer a route to the generation of 3-D images having all the depth cues used by the human vision system. Reconfigurable computer generated holograms allow interactive display of computer held data and synthetic objects. The available number of pixels within the computer generated hologram (CGH) constrains the image size and field of view of such holograms and up to 1012 pixels are required to generate full parallax images having widths of -5OO mm and a field of view of This has significant implications on both the computation and electro-optic replay of CGH images. To fmd practical applications, such CGH display systems require electro-optic modulators which deliver a spatial band width product (SBWP) significantly higher than currently available electro-optic modulator or display solutions. A new electro-optic modulator system has been developed by the authors to replay dynamic holographic images. This Active TilingTM system offers a route to replay giga-pixel CGH images with video refresh rates. High speed, medium complexity electrically addressed spatial light modulators are combined with a high resolution optically addressed spatial light modulator to provide ultra-high complexity, video frame rate holographic data suitable for coherent readout. Keywords: Electro-holography, Computer Generated Holograms, Volumetric Display, Spatial Light Modulator, EASLM, OASLM, 3-D Display. 1. INTRODUCTION It is now commonplace for people to manipulate and work with information in three dimensions within computer environments e.g. CAD, medical imaging, entertainment. However, the normal method of viewing this information is to compute and display a single perspective ofthe dataset. A major challenge remains to produce solutions for displaying three dimensional computer images in a comfortable and natural way. Any display solution must take into consideration the nature of the information being displayed, the requirements of task, the viewer's environment and the human visual requirements i.e. depth cues. Additional problems arise if multiple people wish to share the same 3-D information, particularly ifnormal human interactions are not to be impeded. The human vision system infers depth from a range of cues available within the scene. Whilst it is acceptable for one or more depth cues to be absent from a scene, it is important that cues which are present should be consistent. A number of these depth cues can be reproduced on high fidelity 2-D images. These psychological cues e.g. occlusion, known size, shading and shadows, and object motion, are learnt by the viewer through their life and do not require viewing with two eyes. Current 2-D rendering techniques and displays implement these cues very successfully. * Correspondence: Email: mstanleyldera.gov.uk; WWW: http://www.dera.gov.uk; Telephone: (44) 01684 895422; Fax: (44) 01684 896530. In Practical Holography XIV and Holographic Materials VI, Stephen A. Benton, Sylvia H. Stevenson, T. John Trout, Editors, Proceedings of SPIE Vol. 3956 (2000) • 0277-786X1001$15.OO 13