h a l f b a k e r y"Bun is such a sad word, is it not?" -- Watt, "Waiting for Godot"
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We've all been in situations where we'd rather somebody else wasn't
looking over our shoulder at our computer screen. Maybe you're
drafting MaxCo's latest patent while on a plane, or composing a
threatening anonymous email whilst sitting in a crowded café.
Fortunately, MaxCo has the solution
with its revolutionary new
ScreenShades. Simply affix the Bluetooth transponder to the corner
of your screen using the suction pad provided, install the
ScreenShade software, and don the stylish ScreenShade glasses.
The screen-mounted transponder detects every refresh of the screen,
sending a signal to the glasses. The ScreenShade glasses are a pair
of rapid-response LCD shutters which, in response to the signal from
the transponder, open to let you see only every third refresh of the
screen. Meanwhile, the ScreenShade software displays noise
(created from a scrambled, rotated and flipped version of the screen
image) on your screen for the other two out of every three refreshes.
As a result, bystanders see nothing but a scrambled mess. You, on
the other hand, see a perfect screen image, slightly dimmer and
with a lower refresh-rate than normal, but otherwise quite
acceptable.
Laptop/Notebook Video Glasses
http://www.bitssite...sses/accessory.html
I wonder why these video glasses, or something like them, wouldn't work or could not be adapted to work the very way this idea describes. It's not "bluetooth", but it would be entirely private. [jurist, Dec 30 2008]
[link]
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"Them" are'nt going to like this. (+) |
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"with a lower refresh-rate than normal" |
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<Forgets to turn ScreenShades off> Walks into fast moving wall </fttsso> (+) |
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"Them" may have high-speed cameras. |
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Lack of persistence of vision might make this unusable, also. |
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Good idea, though. I'm sure its workable somehow. |
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Them may indeed have cameras (in fact, any digital camera
would do, provided you took several shots of the screen with
an exposure of 1/100th of a second or less). However, it
would prevent casual over-the-shoulder spying. |
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As for persistence of vision - yes, the screen would look a bit
jerky, like an old movie. I don't know the refresh rate of
modern screens, but I'm guessing it's 100Hz, in which case
you'd see it at 33Hz - fairly watchable as a movie, and
certainly adequate for writing and so on. |
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Wouldn't it be simpler to just turn off your screen and have everything go to the glasses? You can do this with projectors or external screens. |
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Simpler....exactly. That's the problem. |
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I did a quick search to find out what a refresh rate is. I did this because I didn't believe it would work and I still don't. I'll grant you that my actual knowledge of these things is minimal at best, BUT... |
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I gather that it would be normal for my screen to have a refresh rate of about 30 times per second. |
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So the phrase: \\The screen-mounted transponder detects every refresh of the screen, sending a signal to the glasses.\\ sounds to good to be possible. The glasses would also have to react in time. |
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Am I right in understanding that you assume the screen changes all the individual pixels 30 times a second? In the case of the halfbakery for example I would think it much more effective to only change those bits that actually change. |
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I don't really understand what pixel is but I gather that my screen is made up of thousands of little lights that light up to give me a sense of a picture. Is it really true they ALL are refreshed at EXACTLY the same time 30 times per seond? Or does it work in waves? Why would the red "main index" sign at the bottom of the screen need to be refreshed all the time? |
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Sorry for my ignorance but I just don't believe this would work. Could someone with actual knowledge explain it to me like I am a four year old? |
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Well, the basic principal would work for CRT monitors. I
know because I've used a 3D graphics system which had LCD
glasses: the screen displays left and right images on
alternate refreshes, and the glasses synch with that to give
the impression of a stable 3D image. (That's every 2 frames
instead of every 3, but we're in the right ballpark). |
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As far as I know, the whole screen is refreshed every time,
not just the pixels that change. So, this should work. |
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\\So, this should work.\\ Well if you say so, bun well earned. |
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Most software tries to limit updating as close as it can to the bits that actually change, approximating to save time. However, this is only on the video card side of things; the monitor doesn't know or care what bits actually change, it just refreshes everything, usually 60 times a second. Many monitors can handle speeds of 120hz but most LCDs can't. |
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Hmm - so, if the standard refresh is 60Hz and you saw every
third frame, you'd be watching at 20Hz which might be a tad
flickery (though less so for relatively static images such as
text). At a pinch, you could probably use every second
frame instead (giving the non-ScreenShade wearing
overlooker an equal mix of noise and image), giving you a
30Hz image, which would probably be adequately sufficient
enough. |
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The glasses [jurist] linked to would be great, except that the resolution is far too low. |
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[+]
are you able to read this? |
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[xandram] I am indeed, and thank you. |
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[jurist] et al - yes, "Glasstron"-type goggles are a good
solution (and higher-res versions exist), but they prevent
you from seeing what's around you (I think; perhaps semi-
see-through versions are available), and have fixed
resolution; ScreenShades would be considerably simpler,
could be bluetoothed and cordless, exploit the full
resolution (though not refresh rate) of any monitor, and
let you see what's around you (albeit in a rather flickery
way, not unlike Xenzag's 23.976 fps Glasses, q.v.). |
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