A device, method and computer program for determining the distance or position of a camera relative to a light source based on an image of that light source captured by the camera. The device comprises a coded light detection module for detecting a coded light signal modulated into the light from the light source. The coded light detection module is configured to retrieve one or more physical dimensions of the light source based on the coded light signal from that light source. Further, the device comprises an image analysis module configured to determine a distance of the camera from the light source, by performing a geometric perspective calculation to compare the one or more retrieved physical dimensions with one or more apparent dimensions of the image of the light source.