Target Speed Estimation using a webcam

Hi,can anybody tell me how to detect the distance of a moving target using a webcam(in real time). I want the distance to change relatively according to the motion of the target.We mark a particular object as a target and should calculate the distance of the moving target .Is there any possible solution for this? Any sample codes would be helpful .

Regards, Niranjan

Answer 1

[Walter Roberson]

You need a bound on the size of the object in order to estimate the distance to the object. Unless you have information about the size of the object, you cannot tell the difference between a small object that is near-by and a large object that is further away.

If you have an estimate of the size of the object, then you can estimate the area of the object. Then measure the area of the object in the image, and use some trigonometry to estimate the distance.

Note: if the object is sufficiently close to the webcam lens, you may also have to do some correction for off-axis optical distortion.

Answer 2

[annna]

Will you please explain how can i find the distance when I know the original dimensions of the object. The trigonometry, what should it be?