Software that uses algorithms to interpret image data, either static pictures or video. For example, it might be used to recognise faces in a picture so that they can be more easily labelled, or to recognise hand gestures using the computer's camera. Before GPS was common in phones, some applications would match the image on the phone with known landmarks to enable location-specific services such as historical information or geo annotation. Similar techniques are also common in augmented reality systems that overlay digital imagery over a live feed of the real world. The accuracy of the image recognition can affect the user experience.