Abstract: Methods for performing a calibration process for outward-facing cameras on devices such as head-mounted display devices are disclosed. Extrinsic parameters of the camera are first estimated using inputs to the calibration process such as information from an inertial measurement unit and points of interest within images captured by the camera that are tracked with time. Then, extrinsic and intrinsic parameters are concurrently determined in an optimization problem such that updated values of said parameters may be stored and used by applications that run on the device and make use of the camera. The calibration process may be extended to concurrently calibrate multiple cameras based, at least in part, on information from the inertial measurement unit that is local to the camera.