searcy@bgsu-stu.UUCP (todd Searcy) (02/23/90)
Have anyone heard about a study put out by the M.I.T. Media Lab concerning people perception of HDTV? The study stated that relatively speaking, people can not tell the difference between HDTV and NTSC. Come o, be for real! I am doing a paper on onesde and perception of the quaility of the image on television sets. I know there have been many studies looking at theeffects of the VDT(computer workstation) and attitudes towards work. I`m interested in the home television receiver If you know of any research on this topic or anything that might be closely related could you pass it on? Thanks. I have seen HDTV and I`ve seen NTSC. Believe me there is a big difference. Or is there? :). Or is there? :) Thanks again. Searcy@barney.bgsu.edu
dave@imax.com (Dave Martindale) (02/27/90)
In article <5461@bgsu-stu.UUCP> searcy@bgsu-stu.UUCP (todd Searcy) writes: > > Have anyone heard about a study put out by the M.I.T. Media Lab >concerning people perception of HDTV? The study stated that relatively >speaking, people can not tell the difference between HDTV and NTSC. >I have seen HDTV and I`ve seen NTSC. Believe me there is a big difference. >Or is there? :). >Or is there? :) Thanks again. Searcy@barney.bgsu.edu There is a difference between NTSC and HDTV - if you sit close enough to the screen. NTSC television is intended to be viewed from a distance of about 10 times the picture height. At this distance, one scanline pair is about 1.5 arc minute high as seen from the viewer's eye - not bad, considering that the eye's resolution limit is around 1 arc minute. The horizontal luminance resolution is somewhat worse than this, and horizontal colour resolution again worse. Still, an off-the-air NTSC signal (or one from a video disc) displayed on a good NTSC monitor will look pretty close to sharp when viewed from 10 times the picture height. At that distance, a HDTV picture will appear wider, but not much sharper. However, HDTV is intended to allow you to view from about 3 times the picture height. At that distance, the resolution difference between HDTV and NTSC will be readily visible. (HDTV has only about twice the resolution of NTSC, so I can see where moving up to 5 times picture height is justified, but not 3 times). To really compare NTSC and HDTV side-by-side, you need to use an HDTV screen that is 2-3 times as large as the NTSC one, or place the HDTV screen a factor of 2 or 3 closer to the audience. You want to demonstrate how much larger an HDTV image can be and still retain acceptable sharpness, not that HDTV looks sharper at "normal" viewing distances. I've seen a NTSC vs. HDTV demo put on by the CBC that suffered from just this flaw. Both CRT's were located in the same plane, so the viewing distance was the same for both. The NTSC image was actually slightly larger than the HDTV one, and most of the audience was far enough away from the screens that the resolution difference was not very significant. In addition, the NTSC set was brighter than the HDTV one. Thus, it's not too surprising that I preferred the NTSC image half the time or more - not what the demo was intended to demonstrate, I'm sure. Dave Martindale