1. A method for calibrating a stereo see-through HMD (head-mounted display) for augmented reality, the method comprising the steps of: displaying a 2-dimensional marker image on each eye display of a stereo HMD for view by a user, wherein the 2-dimensional marker images are displayed with an offset so as to induce a 3-dimensional marker that is perceived by the user as being at a distance away from the user; aligning the 3-dimensional marker image with a preselected reference point; collecting calibration data associated with the alignment; and computing a model of the HMD using the collected calibration data.