Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 (Tek) 9/28/84 based on 9/17/84; site shark.UUCP Path: utzoo!watmath!clyde!burl!ulysses!gamma!epsilon!zeta!sabre!bellcore!decvax!tektronix!orca!shark!hutch From: hutch@shark.UUCP (Stephen Hutchison) Newsgroups: net.graphics Subject: Re: Stereo Picture TV Message-ID: <1458@shark.UUCP> Date: Tue, 9-Jul-85 17:43:29 EDT Article-I.D.: shark.1458 Posted: Tue Jul 9 17:43:29 1985 Date-Received: Sat, 13-Jul-85 07:32:07 EDT References: <8794@ucbvax.ARPA> <5760@utzoo.UUCP> Reply-To: hutch@shark.UUCP (Stephen Hutchison) Organization: Tektronix, Wilsonville OR Lines: 29 Summary: In article <5760@utzoo.UUCP> henry@utzoo.UUCP (Henry Spencer) writes: >There is also a persistent technical problem, in that the 3D image one >gets from orthodox techniques (like polarization) has some tendency to >produce mild eyestrain. The difficulty is that it requires viewers to >vary the convergence of their eyes (which is a function of how near the >objects appear to be) independently of the focus of the eyes (which is >a function of how far away the light-emitting screen is). Most people >are not used to this, and I am told that it gets uncomfortable after a >while. (Either I don't have a problem with it, or I've never watched >3D material for long enough to run into trouble.) >-- > Henry Spencer @ U of Toronto Zoology > {allegra,ihnp4,linus,decvax}!utzoo!henry Separating convergence from focus as a long-term thing is *VERY BAD*. I have mild systemic damage to my optic chiasm (which organizes much of the binocular information from the eyes) because I have accidentally done this (a result of adult ambliopia). What you get is the inability to correctly track objects moving toward you quickly, and difficulty determining exactly how far away things really are. The real result of this is a drastic reduction in my response to depth-cued stimuli; it takes longer to figure out what's happening, ergo I have up to a 3-second (measured) lag in response over some other folks. Convergence and focus are interdependent systems, and it would be very very bad to train them to operate independently. Unfortunately this is what would happen if people watched a lot of 3-d that works that way. Hutch