kevinc@cs.AthabascaU.CA (Kevin Crocker) (04/09/90)
In article <77100014@p.cs.uiuc.edu> moran@p.cs.uiuc.edu writes: >[material deleted to conserve] >typical, but I wonder how many people have eyes that are less than >balanced in their handling of vision who may not be particularly aware >of it because they haven't been to an eye doctor in a while. >The brain does a lot of compensating for less that perfect >eyes. What I'm saying is that stereo may be strong cue for less people >that you think, but like I say, I don't have any statistics. > I know that my eyes are not very good as I see my doctor every month. I would like to think that my brain has made a lot of compensations for my poor vision, but if so, then either my brain is getting worn out or my eyes really are getting very poor. :-) One thing that my ophthamologist does not seem to be able to pin down is a particular problem that I have had since childhood. Every now and then the "levels" of depth get all confused for me. One example is that when I look at characters on paper quite often the characters jump out from the paper and look like they are floating about 2" above the paper. Another example is that I often see colours at different depths. I have been tested for depth perception and have been told that my depth perception is extremely acute as well as my colour perception. Alas this makes up for the fact that my resolution and convergence are abyssmal. I have seen some of the stereoscopic movies and have had an extremely hard time with them. Sort of like the crazy cartoons that try to exaggerate the depth by making things look like they leap out at you. I can't remember the movie, but in one scene a roller coaster was coming towards the viewers with the intent that the audience would experience a holographic sensation. Well I almost had a heart attack. After picking myself up off the floor I noticed that noone else had reacted the same. Kevin -- Kevin "auric" Crocker Athabasca University Inet: kevinc@cs.AthabascaU.CA UUCP: ...!{alberta,ncc}!atha!kevinc
mitchell@cbmvax.commodore.com (Fred Mitchell - Product Assurance) (04/10/90)
The problem I find with stereo devices (aside from the flicker) is that the eyes aren't focusing at the expected distance that the stereo view would suggest (obviously), being fixed at the distance of the monitor (or movie screen). This causes me extra eye strain; I wonder if others have the same problem. Also, the stereo effect never looks totally 'natural', probaly for the same reason. Any comments? -Mitchell
bart@amiga.UUCP (Barry A. Whitebook) (04/11/90)
In article <614@auvax.AthabascaU.CA> kevinc@cs.AthabascaU.CA (Kevin Crocker) writes: )I have seen some of the stereoscopic movies and have had an extremely )hard time with them. Sort of like the crazy cartoons that try to )exaggerate the depth by making things look like they leap out at you. if anyone IS seriously interested in an analysis of factors for determining proper creation/display of three dimensional "movies", i strongly suggest finding a book published in the 1950's on the subject of stereoscopic motion picture photography by one raymond g. spottiswood (may be focal press). he covers the basic equations for setting up stereo images based on screen size and viewer distance. -- // Bart Whitebook | {|V|))) |\\ | 16795 Lark Avenue, Suite #106, Los Gatos, CA 95030 | O/O ?))| | UUCP: pyramid!oliveb!amiga!bart | { _ } )\ | \\ BIX: amiga_bart | \ // |//
srnelson@nelsun.Sun.COM (Scott R. Nelson) (04/11/90)
From article <10748@cbmvax.commodore.com>, by mitchell@cbmvax.commodore.com (Fred Mitchell - Product Assurance): > > The problem I find with stereo devices (aside from the flicker) is that > the eyes aren't focusing at the expected distance that the stereo view > would suggest (obviously), being fixed at the distance of the monitor > (or movie screen). This causes me extra eye strain; I wonder if others > have the same problem. Also, the stereo effect never looks totally 'natural', > probably for the same reason. Any comments? I find that if the object being viewed does not jump out of the screen, but appears to go back in, I don't get eye strain. Those who were fortunate enough to attend the 1989 Siggraph film festival will remember that Pixar's film "Knickknack" seemed much more natural than most of the other 3D films because it did not attempt to use extreme stereo effects such as having objects jump out of the screen at you. I found that the Pixar film looked very "natural" to me. If the image is antialiased, whether wireframe or solid, it causes less eye strain. This is much more important for wireframe objects since they have so many more edges than polygonal objects. Flicker is definitely a problem. Even those systems with 100Hz updates (50 Hz per eye) have apparent flicker. Technology will have to advance some more before this problem is solved. ----- Scott R. Nelson ARPA: srnelson@sun.com Sun Microsystems UUCP: <most-backbone-sites>!sun!srnelson "Proofread carefully to see if you words out."
lmeyer@well.sf.ca.us (lhary meyer) (04/14/90)
In response to whitebrook@commodore: THE reference for the proper analysis of stereo movies is "Foundations of the Stereoscopic Cineam" by Lenny Lipton. zIt can be had from Reel 3D @ 213-837-2368. They are the #1 source of 3D info and paraphenalia. Spotiswoode's work is very dated and partially erroneous. Re errors and eyesprain :>) The two worse causes are divergence of the images and vertical parallax. Both require very distressing eyes movements. Flicker is still visible at 100 HZ (50 per eye) but is substantially gone at 120 Hz. I can't imagine where Scott Nelson has ever seen a 100 Hz. stereo display, as all Stereographics and Tektronix systems work at 120 Hz.