Direct Views incapable of Full HD Resolution? - AVS Forum
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post #1 of 11 Old 04-12-2002, 11:10 AM - Thread Starter
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hey all,

good to see a place just for fans of direct-view tvs. i like knowing i can watch letterboxed movies and play ps2 without burning a hole in my thousands-dollars hardware, don't you? :D

anyway, i'm curious about something-- i've seen some information floating around about direct-view tvs not being able to fully resolve 1920 x 1080i. apparently, from what i gather, something about the filtering process for rca standard color in a tube (perhaps involving the shadow masking or something...) prevents the full number of pixels from physically manifesting onscreen. apparently 7" crt projectors resolve more detail and 9" crts are the only ones that actually display absolutely all of it. i was wondering if the limitation manifests itself in the 1080 horizontal lines (that give us detail) or the 1920 vertical lines (for density). can anybody comment on this? is it true or just some anti-tube dogma put out by our projector-loving friends?

-dan

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post #2 of 11 Old 04-12-2002, 01:26 PM
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I don't know the specific resolution that a direct view can resolve, but I am quite certain that it is nowhere near full HD resolution. I have seen HD on my Panasonic direct view set as well as a large rear projection set and my set definitely doesn't show as much detail. If I were a betting man, I would guess that my set shows somewhere around 800x600. It still looks good, but it doesn't carry quite the WOW factor that a projection set can deliver.
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post #3 of 11 Old 04-12-2002, 02:17 PM
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I don't buy it. Take the Princeton Graphics AF3.0HD, for example. It's only a 32" tube, but it is widely regarded as a studio-grade HD monitor.

One thing to keep in mind is that LCD and DLP projectors add an ARTIFICIAL amount of detail. For watching video, you don't want to have clean, hard-edged pixels. Those hard edges create aliasing, which they have to resort to using a low-pass filter to minimize.


Finally, some of the highest resolution displays have traditionally been direct-view CRT computer monitors. Because you want hard-edged pixels, for computer applications, the bandwidth of these monitors is even higher than the pixel count would suggest. Sure, there are some high-res projectors, but even recently, it seems that the direct-view CRTs have had a solid lead on resolution.


Obviously, I'm not saying that CRTs will necessarily be better - you mostly have to look at the bandwidth and dot pitch (and consider what kind of mask it is).
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post #4 of 11 Old 04-12-2002, 06:37 PM
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Consumer direct view HDTVs can't do full HD resolution, not even close. Typically their horizontal resolution is 800 - 900 (vertical) lines; they can scan 1080 horizontal lines but the true resolution is less because of scan line overlap. The highly rated Princeton advertises 800 x 600 resolution.

Which is fine. This looks vastly superior to NTSC which is typically less than 400 lines by less than 480 lines resolution. Lots of HD signals don't reach full maximum HD resolution of 1920x1080. And resolution isn't the only important picture characteristic anyway. Direct view TVs produce a fine picture with few motion artifacts, accurate colors, smooth gradations of brightness and a wide range of contrast between the deepest blacks and the brightest whites.
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post #5 of 11 Old 04-13-2002, 08:14 AM
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Greetings,

Maybe I can help shed some light on the subject. I have the Princeton AF3.0HD and while Princeton claims it to have 800x600, Joe Kane has measured it to be 800x720. This allows for this monitor to resolve the 720p vertically. Now, no Direct-View monitor has approached the 1920x1080 resolution yet because it is extremely difficult, there are dot-pitch issues, shadowmask issues, size issues, etc. But remember that when we speak of 1920x1080 we are speaking of 1080i which means that there is only 540 vertical lines on the screen at once - not 1080. There are only a few 9" CRT front projectors that can resolve the 1080p format and those need a de-interlacer such as the faroudja or the runco in order to receive a 1080p signal.

Also, it is important to take into account that on a smaller screen it is harder to see the pixels, when you blow up the picture each pixel becomes bigger. So on a bigger screen we need more pixels to give the illusion of the resolution that a direct-view may have with less. Is there less detail? Technically yes, but how much of that detail can the human eye see? That's another question.

I hope this helps,
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post #6 of 11 Old 04-14-2002, 02:27 AM
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My Toshiba 34" wide screen direct view may not be able to fully resolve 1080I, but I don't think my eyes could see the difference if it could.

I wish 720P had become the accepted standard because I can see the occasional interlace artifacts of 1080I
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post #7 of 11 Old 04-15-2002, 05:17 AM
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I am estimating that the best resolution of a consumer grade direct view TV is about 1000 max pixels across. This is based on resolution equal to a spot as small as spanning any two of the three color stripes given the typical dot pitch, for a 36 inch screen it is around 0.8 mm in the center and 1.0 mm at the edges.

Computer grade screens with dot pitch in the 0.28 range do a lot better. There has been a Sony 16:10 21 inch monitor that, given the dot pitch, can do nearly 1920 x 1080.

When trying to measure fine resolution, often the black vertical lines dividing the color stripes confuse the eye. Spanning two of the three colors (or half of one, all of a second, and half of the third) is needed to get at least a pastel color as opposed to a deep color since resolution implies white on black.

Even though the resolution is less than 1920 across, picture details can still be positioned at any of the 1920 possible positions. It is just that the spot can't be made small enough for three of the finest details in a row to all be distinguished.

Video hints:
http://members.aol.com/ajaynejr/video.htm

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post #8 of 11 Old 04-15-2002, 08:17 PM
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Digital is 1080i my F38310 has 1280 X 1080
1,382,400 pixel screen. I was told digital was the best, it's being said you need 1920 X 1080. I thought that 1080 X 1080 was Digital AKA High Definition. Just what is HD if I have 1280 X 1080, 200 over the 1080 on the first set of numbers. I have seen all those square pixels with my own eyes, IMHO I don't think you could get any more of the square critters on a screen!


I view movies on Digital pay TV channels through www.sectv.com digital choice, for all of the many HBO & Cinemax. I also can record movies in Dolby Surround with the black bars in OAR on my old never used till 2 months ago 1984 NEC HI-FI Vcr. Late at night movies to see if I want the DVD if available to purchase in the wide screen and Dolby Digital Surround as I seen and heard on my HDTV.


People viewing my HDTV, are *insisting* they are looking through an open window on a clear day view. On inside shot seeing a crystal *clear* view. I am using our AVS sponsers www.bettercables.com Silver Serpent component cables from 2 Sony DVD mega changers and Digital Choice from my cablevision company. Please tell me what am I missing here? I am here to learn and discuss, I am all *ears* to this quite interesting HD/Digital discussion.:)

P. S. New movie on clickable URL in my signature box 4/16/02. What is the name of this movie. Best viewed on HDTV in *full*.
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post #9 of 11 Old 04-16-2002, 02:19 AM
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Quote:
Originally posted by Allan Jayne
I am estimating that the best resolution of a consumer grade direct view TV is about 1000 max pixels across. This is based on resolution equal to a spot as small as spanning any two of the three color stripes given the typical dot pitch, for a 36 inch screen it is around 0.8 mm in the center and 1.0 mm at the edges.
Um, you actually want lots more dots than pixels, otherwise the pixels beat against the dots, and you get moire patterns.


So, does anyone know why the dot pitch on direct-view TVs is so much worse than computer displays? Is it really just a matter of brightness vs. sharpness? Or is the added cost really that much, for such large tubes?


All this display business is so annoying. I just want to stimulate my optical nerves, directly. Then, you could get true stereoscopic 3D, with depth-of-field and everything!
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post #10 of 11 Old 04-16-2002, 05:27 AM
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>Or is the added cost really that much, for such large tubes?<

I think that is it. I also think that much of this market is charging "what the market will bear" rather than "cost + a percentage" based pricing both for TV's and monitors.
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post #11 of 11 Old 04-16-2002, 06:28 AM
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Both of your posts were on money and dots. I do hope we resolve this before the 3 of us have to go and buy our new HD HDTV, what ever it has to be composed of to get HD, and Digital to be happy.:)
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