Instant Rephotography.

When traveling, a very common issue is to ask for the help of a stranger to take a photo on a touristic spot. Indeed, often the results of this short collaboration are not as previously imagined. In this paper, we introduce the concept of instant rephotography, a technique based on a simple and intuitive user interface, and in an efficient and low cost algorithm that finds the matching between two images. The user interface guides the photographer to position the camera in the right place that was once imagined by the camera owner, automatically taking the new photo. To correctly choose the new photo, we propose an algorithm based on ORB (Oriented FAST and Rotated BRIEF) feature points acquired from the reference and current photos, and on inertial sensors embedded in the photo device, a smartphone. To validate the concepts introduced, we implemented an Android App called Smart-Tourist Camera, conceived to help tourists to take good pictures during travels. Three different user studies involving 124 volunteers were conducted and results have shown that the photographs taken with the application are perceived as better than otherwise, and that users would use the App during their travels.