Silly question about flashing...
February 6, 2008 7:44 AM Subscribe
I have a question about persistence of vision and flashing lights... There will be maths and biology involved.
posted by twine42 to Science & Nature (3 answers total) 3 users marked this as a favorite
Imagine you have two LEDs. They each produce one hypthetical unit of light (1 HUL if you will). If they're both turned on, they produce a combined 2HUL.
Now imagine that they flash at a rate greater than 25fps in a way that when one is on the other is off.
Ideally they are producing 1HUL. In reality the light up time probably means it's a little less than this. But here is my question:
What does the human eye *think* they are producing? Do you see the equivalent of 1HUL, 2HUL or somewhere in between? Does it matter if you are looking directly at the LEDs or at a surface being illuminated by them?
I've used 25 fps here since with cartoons a frame rate above 25 fps creates a moving image... it may be a red herring.