Hi Prasad,

Inline replies below:

> 1. Does it stores a pattern and matches it when live camera is running?

Yes.

> 2. Can i work with only single camera OR a pair to get the marker? Does
> camera_info topic requires stereo camera?

You don't need a stereo camera setup. Since you know the size of the
marker in advance, you can estimate it's 3D position with a single
camera.

> 3. Will i be able to work on ar_pose_ekf to estimate accurate position using
> single camera? Since i have memory constraints so i am avoiding stereo
> vision process. I have Hokuyo-URG-04 and Odometry sensors. I want to fuse it
> with my existing sensors to get more precise localization inputs.

The ar_pose_ekf was developed to work in conjunction with ar_pose. If
you have more than one camera, the different estimates for the marker
pose can be merged together using ar_pose_ekf. If you are only using a
single camera, you probably don't need to use ar_pose_ekf (although it
might help smooth out the result - I haven't tested it myself).

> 4. How it works in light different light intensities?

It should handle reasonable variation in the light conditions. The
best thing would be to just try it out.

> I hope all my questions are relevant.

Let me know if you need any further help!

Ivan Dryanovski