Hello. You need to say a bit more about what your sensor is measuring. If you have an image sequence, for instance, then you need to extract the car from the background and track it's position, e.g., using a Kalman filter. The filter estimates the position and velocity of the car. Or maybe you have a Doppler radar sensor, which measures radial speed directly. Please be more specific in your question to get more helpful answers.

Thank Graham. 

Now, I am using only a web cam for this case. I watch videos in the youtube about it, for instance:  

a) https://www.youtube.com/watch?v=m_Y3Ym5n8Vc

b) https://www.youtube.com/watch?v=66Pv5jnxUVI

In this videos use only the web cam. If you have any example about this case I would appreciate.

Regards

https://www.youtube.com/watch?v=m_Y3Ym5n8Vc

https://www.youtube.com/watch?v=66Pv5jnxUVI

Hi Rodrigo.

I do not have much practical experience with object tracking, but perhaps these links might be of some help to you:

• Track on the StackOverflow about speed measurement: http://stackoverflow.com/questions/12445416/opencv-continous-speed-measurement-using-camera
• Article on the same subject: http://www.mdpi.com/1424-8220/10/5/4805

Cheers,

Luiz

Is there any software which gives velocity of a car using only webcam??

Hi,

you can't determine the velocity directly from the video stream. as Graham suggested, you have to detect the object first, track it and compare the new and old locations.

If you don't care about the accuracy of your calculations, you can approximate the velocity in terms of pixels/seconds.

If you need more accurate result, the you need to calibrate your camera to determine its parameters such that you know the trajectory of your object and its movements from real world model to image model and define the final result in terms of m/s.

Ola

can you share your source code with me?

please

think about depth of moving object !

i have no experience but i think it is impossible to calculate the depth with just one camera. or if you don't want to calculate the depth you have to get some environment parameters.