In the old day when we point the camera at a CRT monitor we see hum noise, something like horizontal bars rolling up/down
Today when pointing the same camera at the LCD monitor we don't see such thing anymore
Why ?
In the old day when we point the camera at a CRT monitor we see hum noise, something like horizontal bars rolling up/down
Today when pointing the same camera at the LCD monitor we don't see such thing anymore
Why ?
Because the pixels are dead slowly switching, compared to a crt. The crt pixel fades in milli(?micro)seconds, and thats the reason for the bad videocamera picture. The slow pixels in lcd displays are responsible for badly visible fast moving things on screen.
we don't talk about the motion video. I recall in the old RCT monitor, even with still images there's also rolling hum-noise.
In other words, if a fly watches the LCD monitor what would the fly seeing ?
Ps. the fly'eyes can see much faster than human eyes
The fly would only have a problem with the crt.
LCD monitors don't refresh the screen like CRTs do, they don't need to.
I used the highest refresh rate available with my CRT monitor, 85 Hz. That made the flicker imperceptible (except to a camera that periodically blinks at the same time that a horizontal line on the screen does).
With my LCD, I use the lowest, 60 Hz.
A steady image.
Then the fly sees the CRT like rows of strobe lights.
Thanks you guys, that make sense now, ...about our little fly friend ;-)
But I still wonder why it happens way? It's because, I know the video sent to the LCD is the same as it has been sent to the CRT monitor. That means, the video is scanned line by line, pixel by pixel, left to right top to bottom. So, how can the image appears as a still image at once ?
Hmmm why ?
Remeber the RADAR screens in movies made in the 70s and 80s where the bright stripe moves around the display leaving behind an image that gradually fades?
With a TV screen the bright line is horizontal and moves vertically at a much higer rate and the fading is also much quicker.
the bright line itself consists of a dot produced by the scanning beam, but as each pass across the screen takes less than 0.1ms I don't think even the fly can resolve that motion.
with an LCD there's no fading between scans the pixels just update in order and stay the same until the next update
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m e
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.Oh, I see.
So, if I heard you right, each pixel on the LCD screen somehow has its own memory, or a capacitor to hold up the charge, even the scanning time or "charging time" for each pixel is just a few nano second according to the video signal
Hmmm, that's sound possible but I don't know they people make it, or there's a real memory like DRAM or SDRAM???
Wonder whatever it is...
Thanks,
hum
see
tor,
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. y o eI think it all makes clear now,
Thanks guys for sharing your knowledge
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