Short · Vision
How can a camera tell how far away something is?
Blink one eye, then the other, and your thumb jumps while the far wall stays put. Two cameras set a little apart measure that shift, and simple geometry turns it into a distance.
Try it yourself
Opens Depth Lab. Change the same thing yourself.
Transcript
How can a camera tell how far away something is? Hold up your thumb and blink one eye, then the other. Your thumb jumps, but the far wall barely moves. Two cameras set a little apart work the same way. Now bring the object closer. The closer it gets, the more it shifts between the two views. Measure that shift, and simple geometry gives the distance. Some cars' safety systems use camera pairs that work this way. Try it yourself at Explainer Tools dot com.