Which webcam to choose for the most accurate determination of the distance to the object?

Question

Pattern recognition

Task: through a pair of webcams, determine in real time the distance to an object moving in the frame. In dim lighting.
What critical parameters of webcams should be looked at first of all, which parameters are secondary, which ones are not particularly important?
How much will the accuracy differ between a very good option and a cheap one for 500 rubles?

Answer 1

It's a good old parallax rangefinder, right? Its accuracy (among other things) will greatly depend on the accuracy of measuring the angle (azimuth) to the object when the webcam tracks its position in the frame. As far as I remember the theoretical foundations, it’s generally enough to know the distance between the cameras (base) and the difference between these azimuths from both observation points when the object is in the center of the frame - after that, the distance is easily calculated by ordinary trigonometry.
Therefore, each camera needs an accurate angle sensor - it, in fact, sets the accuracy. As for the parameters of the camera itself, they may not be too steep, as long as they are enough to drive the object exactly into the center of the frame. The location of the object in the center (in fact, the combination of images from both cameras) must be identified by the control controller, which means that an overly detailed image can complicate (slow down) this identification. Plus, object recognition against the background of other local objects ... In general, take 1 megapixel - I think this will be enough for a start.
As for the illumination of the object, it seems to me that this question is generally irrelevant, since it does not relate to the camera, but to the cost of a pair of LEDs (infrared, if stealth is desired).