Compare/recognize building on mobile cam with earlier taken image

I was wondering if there is any solution in PHP/GD to compare a building viewed with a camera with a allready taken picture of it.

Little explanation: I take a picture from all shops in a mall. Run a script / webpage on my mobile (PHP, Ajax, etc.) and view a shop on the camera. Pling! Shop recognized with one of the pictures on the server.

If so, please give a hint how to start...

Thanks.