5 ms·

Could speed of an object be determined with two front facing cameras? If you knew the distance between each camera and triangulated plus a little math could sp

Could speed of an object be determined with two front facing cameras? If you knew the distance between each camera and triangulated plus a little math could speed be figured out?

icelancer 11y ago
Not necessarily. This is a pretty tough problem. Naively yes you can just compute x-plane distance but what if the target is moving diagonally through the visual plane? Then it is very distorted. Or what if the object is rotating, moving through at least one plane where the two cameras can't track? Direct Linear Transformation is the standard way to do this using a control object (object of precisely known size and measurements) and cameras that don't move. Cameras film the object (usually a big cube), the object is removed, the cameras stay stationary, and anything that goes through that object's field of view can be tracked in all three dimensions. However, the cameras must not be co-linear and must be able to see a point on the object with both cameras, so this means no two front facing cameras, and realistically 4-5 cameras (though 3 can be done sometimes).
TACIXAT 11y ago
A simple way to solve this. Have two cameras (C) facing straight ahead with a known distance (D) between them. When the spot they normally see (X) is blocked, mark the time. (t1-t0) / D C0-----------------X | D | C1-----------------X
- pbhjpbhj 11y ago
  Could you use two vertical strips, calculate the length of strip covered [segment image and use number of pixels as first approximation], assume the articles are discs [or some other assumption depending what you're expecting to measure] and use that to naively alter for objects not moving parallel to the plane of the cameras? Would be interesting to see how accurate you could get given the massive assumptions in play. Known objects would be easier to handle.

Could speed of an object be determined with two front facing cameras? If you knew the distance between each camera and triangulated plus a little math could speed be figured out?

icelancer 11y ago

Not necessarily. This is a pretty tough problem. Naively yes you can just compute x-plane distance but what if the target is moving diagonally through the visual plane? Then it is very distorted. Or what if the object is rotating, moving through at least one plane where the two cameras can't track? Direct Linear Transformation is the standard way to do this using a control object (object of precisely known size and measurements) and cameras that don't move. Cameras film the object (usually a big cube), the object is removed, the cameras stay stationary, and anything that goes through that object's field of view can be tracked in all three dimensions. However, the cameras must not be co-linear and must be able to see a point on the object with both cameras, so this means no two front facing cameras, and realistically 4-5 cameras (though 3 can be done sometimes).

TACIXAT 11y ago

A simple way to solve this. Have two cameras (C) facing straight ahead with a known distance (D) between them. When the spot they normally see (X) is blocked, mark the time. (t1-t0) / D C0-----------------X | D | C1-----------------X

pbhjpbhj 11y ago
Could you use two vertical strips, calculate the length of strip covered [segment image and use number of pixels as first approximation], assume the articles are discs [or some other assumption depending what you're expecting to measure] and use that to naively alter for objects not moving parallel to the plane of the cameras? Would be interesting to see how accurate you could get given the massive assumptions in play. Known objects would be easier to handle.