Augmented Reality iOS App

We are looking to develop an augmented reality application that would require the implementation of object recognition in a known environment. (e.g. an office). The app, written in objective-C for iPad or using Unity, should look for an object in a scene, using the device's camera, match it with known objects and finally provide informations retreived about it. It should work in realtime or near realtime. Please provide examples of past works, and an idea of algorithms and technologies that will be involved in the project.