Abstract: Systems and methods for determining pose using a trained neural network are described, whereby a user device receives image data of a marker affixed to an object to be tracked, provides a set of input data derived from the image data to a neural network stored on the user device, and generates a pose descriptor indicative of estimated pose of the marker based on output of the neural network produced in response to receiving the set of input data. The marker comprises a first surface to convey radiation in a first direction, and a second surface to convey radiation in a second direction different to the first direction, whereby the image processing system determines object pose from captured image data of at least a portion of the radiation conveyed from the first and/or second surface of the marker affixed to the object. Other embodiments are also described and claimed.