osmoviita@cc.helsinki.fi (10/11/90)
I am looking for a graphics workstation or frame buffer which is capable to produce more intensity levels on screen than normal ones. It is intended to be used to produce precicely controlled visual stimuli for our vision reseach measurements. The normal 24 bit full color definition is absolutely not good enough. 48 bits i.e. 16 bits for every color component would be quite optimal. In addition to it there would be gamma correction lookup tables 16 bits in and something more out to make things right for High Fidelity imaging. All that should be double buffered and/or there should be enough bandwidth between frame buffer and memory with some locking system to make smooth animation possible. Indexed color 3 x (8 bits to something more) is better than plain 24 bits if direct color systems with enough bits are not available. This can be done with gamma correction lookup tables if they have bigger outputs than inputs and DACs have enough bits too. I am interested to get information of grayscale systems with high intensity resolution too. I already know that Evans & Sutherland has 9 bits DACs in some product and Pixar has 10 bits output but these are not enough. But who has more? 12 bits per color component is about the minimum but not yet perfect. So the digital to analog converters should be at least 12 bits for each channel. If there is no more than 12 bits then dithering must be used for additional fine tuning and gamma correction must be calculated to the image file, which both take additional processing power. If somebody can help me to find such a High Fidelity graphics workstation or something near it please do so! Kari Osmoviita osmoviita@cc.Helsinki.Fi University of Helsinki Department of Physiology Vision Research Laboratory Siltavuorenpenger 20 J SF-00170 Helsinki Finland