A device for calculating a vehicle trailer pose using a camera is disclosed, including: a camera arranged offset from a tow bar position of the vehicle and configured to capture an image of the trailer; a memory which is configured to provide data at least one intrinsic parameter of the camera; at least one extrinsic parameter of the camera; at least one predefined tow bar position; and a first image from the camera showing the vehicle trailer at a first pose wherein the camera captures a second image showing the trailer at a pose to be determined; a processor configured to provide image analysis and determine at least one feature correspondence between the first image and the second image and calculate a change in the trailer pose between a first pose of the first image and a second pose of the second image based on the determined correspondence.