An AR system includes one or more image sensors arranged to capture image data representing a scene located within a field of view of the one or more image sensors, a display arranged to enable a user of the AR system to observe a representation or view of the scene, and an augmentation engine. The augmentation engine is arranged to process the captured image data to determine one or more visual characteristics for the captured image data and to determine, in dependence on the determined one or more visual characteristics, one or more properties for an image element to be presented on the display. The augmentation engine is arranged to present the image element, with the determined one or more properties, on the display to overlay the representation or view of the scene.