Abstract: A system and method for tracking positions of objects in an actual scene in a wide range of lighting conditions. A vision-inertial navigation system is provided that may be configured to track relative positions of objects of interest in lighting conditions ranging from, e.g., typical indoor lighting conditions to direct sunlight to caves with virtually with no light. The navigation system may include two or more helmet-mounted cameras each configured to capture images of the actual scene in a different lighting condition. A remote processing element may combine data from the two or more helmet-mounted cameras with data from a helmet-mounted inertial sensor to estimate the position (e.g., 3D location) of the objects.

Abstract: A method, a system, and a computer program product for tracking an object moving relative to a moving platform, the moving platform moving relative to an external frame of reference. The system includes An inertial sensor for tracking the object relative to the external reference frame, a non-inertial sensor for tracking the object relative to the moving platform, and a processor to perform sensor fusion of the inertial and non-inertial measurements in order to accurately track the object and concurrently estimate the misalignment of the non-inertial sensor's reference frame relative to the moving platform.

Abstract: A non-eddy current electro-magnetic interference (EMI) shield to prevent or inhibit generation of eddy currents in the shield. The shield may include a non-conductive enclosure, one or more conductive traces interlaced on the non-conductive enclosure, wherein the one or more conductive traces do not form any conductive loops, and one or more ground connections on the one or more conductive traces, wherein the one or more ground connections do not form a ground loop. The EMI shielded electronic device may at least partially encompass an electronic device, such as a magnetic tracker, wherein the EMI shield comprises a non-conductive housing, with conductive traces interlaced on the housing, in a pattern or arrangement such that the conductive traces do not form any conductive loops. One or more ground connections may be provided for the one or more conductive traces.

Abstract: Technology described in this document can be embodied in an optical sensor that includes a rectangular array of at least four photodetector cells of substantially equal size. An opaque mask is affixed over the rectangular array. The opaque mask defines a substantially rectangular aperture for admitting light onto only a portion of the surface of each of the at least four photodetector cells, where the aperture can be centrally positioned over the rectangular array.

Abstract: A helmet mounted display (HMD) system comprising (i) a display device adapted to be positioned between an eye of a person wearing the helmet and a vision-related device; and (ii) a step-in visor which is positioned between the eye of the user and the display device. The vision-related device is removably attached to an accessory joint so that it can be interchanged between an outer visor for use during the day and night vision goggles for use during the night.

Abstract: Aspects of the present invention relate to systems, methods, and computer program products for measuring and compensating for optical distortion. The system includes a plurality of reference marks; a recording device configured to record a first orientation and a first position of a plurality of reference marks relative to a pointing angle of the recording device when an object is located outside of a field of view of a recording device, the recording device configured to record a second orientation and a second position of a plurality of reference marks relative to the pointing angle of the recording device when an object is located inside the field of view; and a processor configured to compare the first orientation and the first position of the plurality of reference marks to the second orientation and the second position of the plurality of the reference marks for measuring distortion of the object.

Abstract: Aspects of the present invention relate to systems, methods, and computer program products for tracking an orientation of a first object. The system includes a light emitting device located relative to a second object at a fixed predetermined position; a sensor having a photodetector array that is configured to receive incident light emitted from the light emitting device, the photodetector array being mounted on the first object; and a processor coupled to the photodetector array, the processor configured to determine the orientation of the first object relative to the second object based on an angle of incident light detected by the photodetector array from the light emitting device.

Abstract: Among other things, positioning a magnetic instrument on a pedestrian; positioning an inertial instrument on a foot of a pedestrian; receiving positioning signals at the pedestrian; aligning the inertial instrument based in part on the received positioning signals; calibrating the magnetic instrument using the inertial instrument; and tracking the pedestrian using the calibrated magnetic instrument and the inertial instrument.

Abstract: Aspects of the present invention relate to systems, methods, and computer program products for tracking an orientation of an object. The system includes a first sensor that measures the orientation of the object relative to an external reference frame and generates an orientation signal based on the measured orientation of the object, the first sensor being subject to drift over time; a second sensor that receives a global positioning system (GPS) signal and generates a drift compensation signal based on the received GPS signal; and a processor coupled to the first sensor and the second sensor, the processor generating a drift-corrected orientation signal based on the orientation signal from the first sensor and the drift compensation signal from the second sensor.

Abstract: An apparatus for measuring an inertial property on a set of one or more axes is disclosed. The apparatus includes a first inertial sensor arranged to measure the inertial property, having a first predetermined resolution and a first predetermined measurement range, and a second inertial sensor arranged to measure the inertial property, having a second predetermined resolution and a second predetermined measurement range. The second resolution is coarser than the first and the second measurement range is larger than the first. A processing system is adapted to receive measurement signals from the first and second inertial sensors and, when the output of the first inertial sensor is within the first predetermined measurement range, to update an error estimate for adjusting the output of the second inertial sensor, based on the measurement signals from the first and second inertial sensors.

Abstract: Systems and methods for tracking the motion of a game controller and a player's body part are disclosed. The method includes receiving a video signal from a webcam, generating movement data corresponding to the motion of the game controller, tracking first predetermined degrees of freedom of motion of the body part, generating feature location data based on a location of at least one identifiable visual feature of the game controller, and estimating second predetermined degrees of freedom of a motion of the game controller.

Abstract: Among other things, first data is received from an inertial tracking device worn by a first person, the first data approximating locations along a first path that was traversed by the first person. Second data is received from an inertial tracking device worn by a second person, the second data approximating locations along a second path, similar to the first path, that is being traversed by the second person. A determination is made about how to guide the second person to reach the first person by using the first data and the second data to correlate locations along the first path and corresponding locations along the second path.