Slashdot Mirror
Human Eye's Oscillation Rate Determines Smooth Frame Rate
jones_supa writes: It should be safe to conclude that humans can see frame rates greater than 24 fps. The next question is: why do movies at 48 fps look "video-y," and why do movies at 24 fps look "dreamy" and "cinematic." Why are games more realistic at 60 fps than 30 fps? Simon Cooke from Microsoft (Xbox) Advanced Technology Group has an interesting theory to explain this all. Your eyes oscillate a tiny amount, ranging from 70 to 103 Hz (on average 83.68 Hz). So here's the hypothesis: The ocular microtremors wiggle the retina, allowing it to sample at approximately 2x the resolution of the sensors. Showing someone pictures that vary at less than half the rate of the oscillation means we're no longer receiving a signal that changes fast enough to allow the supersampling operation to happen. So we're throwing away a lot of perceived-motion data, and a lot of detail as well. Some of the detail can be restored with temporal antialiasing and simulating real noise, but ideally Cooke suggests going with a high enough frame rate (over 43 fps) and if possible, a high resolution.
I, for one, am sick of slow (seconds-long!) pans across scenery that *still* end up with judder and motion blur.
HFR isn't a gimmick like migraine-inducing stereoscopic "3D", it's more akin to adding color instead of relying solely upon greyscale for film presentation.
Like all tools, I'm sure it can be used for both good and evil. Blame evil, jump-cutting directors if the dark side is channeled.
Movies tend to be shot around 1/50" shutter speed, and that creates motion blur. The motion blur actually helps us see the animation as smooth, even at "only" 24 fps. Games on the other hand are razor sharp and will hence look much more like a staccato sequence of images than as an animation.
Or so I was told by a moviemaker
why do movies at 48 fps look "video-y," and why do movies at 24 fps look "dreamy" and "cinematic."
For the same reason children are picky eaters. They say that people have to take three bites of a new flavor to really know if they like or dislike it. I have personally experienced that, going from "wtf this is so wrong" to "ok it's not so bad and I might actually like this" between bite 1 and bite 3. Well, we all grew up consuming 24 fps movies, and anything higher is new and different. Rather than "take three bites", though, so many of us recoil from the different experience and immediately start talking to all our friends about how it looks wrong, concluding that high FPS just looks bad. Try. Three. Bites.
I sometimes ask revealing, often ignorant-seeming questions. Maybe they're harder to answer than you think.
What about our eyes is oscillating?
The whole eye. Our eyes actually cannot detect a static edge, only transitions. The reason we can see non-moving objects is that the oscillations of the eye provide the transitions. There's a simple experiment from long ago which illustrates this vividly: put a black square on a white background, track a subject's eye motion and move that target with the eye motion so that the image is always hitting the retina at the same location, and voila, the subject cannot see that target.
Smart people don't choose to believe things because they want them to be true like you do. An idea doesn't have to give you a warm fuzzy feeling to be true.
If religious people had any proof, it would no longer be religion. Of course they don't, because the supernatural is imaginary. Too many people fail to grow out of their childhood superstitions, and never develop an evidence-based adult worldview.
That would be Pascal's wager. The problem with it is that an all-knowing God would know the difference between you telling yourself that you believe in him in order to secure your salvation vs you actually believing. So... you go through the motions all your life just to burn in hell anyway.
I don't know about you but for me belief is a conclusion I come to based on the evidence I know about, not a decision that I make. Anything else would just be lying to myself. The evidence I see and know about overwellmingly supports evolution. If the reality around me is just an illusion planted by Satan to test me or a corruption resulting from the fall or planted by God to test me then I guess I am just screwed because what I see does not match up with any supernatural creation myth I have ever heard of.
By the way, evolution has nothing to do with purpose, progress or meaning. You have to make that for yourself. Evolution is just change and an explanation of why the change hapens the way it does.
There are several ways to apply temporal antialiasing or "motion blur", each of which is analogous to a well-known spatial antialiasing method. One is to render the scene twice at a slight time offset and average the two; this is the temporal counterpart to FSAA. Or find the motion vector around the frontmost mesh in each 8x8 pixel section of the screen and add a local blur filter; this is more like MSAA. But in the march from 240p (PlayStation and Nintendo 64) to 1080p (current consoles) and higher (PC master race), the preference has been for more detail in each frame rather than a better illusion of motion within a frame.
Unless of course, the mushroom just make you think this is happening.
The other reason is the "sensors" we have are quite poor - the eyeball itself is actually a very low resolution device - the high resolution center part of the eye covers such a narrow field of view that it's practically useless if it was a fixed camera, while the peripheral vision is so low res it's unusable.
Instead, what happens is we evolved a gigantic amount of wetware to process the image into a high-resolution image we perceive - the brain does a lot of visual processing, and the eyes rapidly move (or oscillate) to move the sharp high-res center vision around to give you a much higher "virtual resolution" than the actual Mk. 1 Eyeball can achieve.
Of course, this visual processing comes at a price - optical illusions abound because it's very easy to trick the wetware into seeing things that aren't there, because the information is often interpolated, shifted in time, etc.
That's like saying laserdisc is digital "because it's got pits and non-pits". Except that the length of the pits and non-pits is very much analog. (It's a full-bandwidth FM signal driven to maximum overmodulation. VHS does a similar thing.) In other words, the digital-ness becomes analog if you look even closer.
#naabhaprzrag, #sverubfr-000, #agi-fcbafberq, negvpyr[pynff*=' negvpyr-ary-'] { qvfcynl: abar !vzcbegnag; }
Some representations of what our eyes really see.