何時才有完美的3D顯示器?

r32

本文章最後由 r32 於 2011-4-2 09:22 編輯

http://forums.highdefdigest.com/ ... -frame-rate-34.html

Why 144fps is used in 3-D Cinemas around the world

In commercial 3-D cinemas, a 48Hz 3-D native source will always be flashed on the screen at a minimum of 144fps since engineers have discovered that when 96Hz is used a flicker is seen on the screen by 50% of the people. If the 3-D image is flashed on the screen at 120HZ by a LCOS or DLP Projector most people will not see the flicker but instead experience unnatural 6:4 pulldown (3:2 pulldown judder for each eye). So all 3-D Cinemas flash the 3-D image on the screen at a minimum of 144fps to completely eliminate flicker and 3:2 pulldown issues.

Flat panel 3-D plasma screens are much brighter compared to front projectors, do to the brighter screen on a plasma screen some people have seen flicker at 120HZ with 3:2 pulldown issues. Hopefully future 3-D plasma screens will operate at 144HZ or 192HZ to offer flicker free 3-D performance with no 3:2 pulldown for each eye. DLP and Plasma displays with their fast response times are ideal for 3-D. Some other technologies might take several years to offer good quality 3-D. LCD technology at 240Hz inserts black frames into the 3-D image which results in 60Hz for each eye using 3:2 pulldown. Perhaps future LCD screens with true native 480Hz refresh rates might be able to do 3-D without 3:2 pulldown judder for each eye.

The following are some interesting quotes from pages 46 and 47 of the February 2011 Widescreen Review magazine

“Typically when you see them in the theater they’re operating at 144 Hz. The reason for that? We’re back to 24p, which is the actual framerate that the content resides in, and 144 Hz is what we refer to as triple-flash. So you’re seeing the left eye triple-flash, so 24 times 3 equals 72, plus the right eye triple-flash, 24 times 3 equals 72, so combine 72 left eye and 72 right eye, the projector operates at 144 Hz. A modulator that sits in front of the projector – and it’s actually operating synchronized with that so it’s switching polarization realtime – so that you’re seeing left and right eye information sequentially. And it allows you to use passive glasses, but it requires a silver screen. The general feedback from most users is that they find passive glasses the most comfortable, because they’re lighter and they physically don’t switch. There’s no power to them. You don’t have to worry about ‘are the glasses on?’ There’s no emitters. There’s no challenges like that. In a professional, non-consumer world, medical imaging technicians will only use passive glasses. Primarily because when they’re doing research-oriented work, they find that they are actually over a period of time sensitive to the switching of the glasses, where with passive they don’t see that.”

“The advantage of a single projector that can operate at 144 Hz, basically, is that you can do any of those technologies. We could do passive, we could do active, or we could do passive/active.”

“Today, if you’ve got a Blu-ray Disc player, most of them, when operating in 3-D mode at full resolution, it outputs 24p. Effectively, in that timeframe you’re getting left-eye information and right-eye in a shorter time interval – effectively 48 Hz. So left eye and right-eye combined at 24p. We triple-flash that so the projector actually operating at 144 Hz. Why? Because if we only double flash, 48 and 48, you get 96, you literally start to see flicker. Again, you get down to the dynamics of the human eye. Fifty percent of people at 96 Hz wouldn’t see flicker. Fifty percent would see flicker. When you up it to 120 Hz, basically nobody sees it. At 144 Hz, for sure, nobody sees it. But if we stayed at 120 Hz, you’d have to basically get back to some derivative of 3-2 pulldown. If you go 144 Hz, it’s natural – triple flash. And the beauty of active is that we use exactly the same screen for 2D as 3D. So there’s no need to change the screen.”

r32

本文章最後由 r32 於 2011-4-2 09:35 編輯

Also from the same topic :

"With the Frame Packed Blu-ray 3-D format the 3-D Blu-ray player normally has a HDMI 1.4 output and is able to read the new Multiview Video Coding which is an extension to the H.264/Mpeg-4 AVC video compression standard. This allows two 24fps camera angles to be frame packed into one 24fps image. A frame packed Blu-ray movie will contain two 1920 X 1080P 24fps images for both eyes by vertically packing each image. The frame packed image is 1920 X 2205 pixels at 24fps (The reason why the frame packing technology does not use 1920 X 2160 and uses 1920 X 2205 is because of 45 vertical pixels used as a buffer). The Blu-ray player then delivers the frame packed 1920 X 2205 24fps 3-D signal to the 3D display or 3D projector.

The 3D display should be able to automatically detect the frame packed image and then it is the job of the 3D display to unpack the compressed 1920 X 2205 24fps signal. Inside the 3D Front Projector or 3D display will be a process that is used to turn that compressed frame packed 1920 X 2205 24fps signal into two separate 1920 X 1080 24fps signals. So the final result will be a true 1080P 48HZ source inside the display.

Once those two 1080P 24 frames for each eye are unpacked then the 3D display is suppose to display the image at a minimum of 144HZ (72HZ for each eye). The problem is almost all consumer displays I have seen so far add 3:2 pulldown judder to each eye with 120HZ refresh rate (60HZ each eye). Even if some 3D displays in the future offer 96HZ for 3D that is still below the quality of 144HZ which is the minimum standard in all movie theaters.

To my knowledge there is only one consumer Front Projector on the market so far that offers 144fps and that high-end consumer projector costs $84,995.
"

作者指的是DPI Titan Reference 3D.