While we are thinking to measure distance or size of an object or something else, first we will need a measurement tool for doing it. but now a days it is not necessary to keep any measurement tools to do this as we can use our android smartphones to find a distance, and height, width and other size of an object using our phone camera. no special hardware requirements in smartphone are needed to find size and distance of an object or area. but all we need to have to do this is just an auto focus camera in our smartphone.