Abstract: One embodiment of the present invention is a method for computing a first gaze axis of an eye in a first coordinate system. A camera is focused on the eye and moved to maintain the focus on the eye as the eye moves in the first coordinate system. A first location of the camera in the first coordinate system is measured. A second location of the eye and a gaze direction of the eye within a second coordinate system are measured. A second gaze axis within the second coordinate system is computed from the second location and the gaze direction. The first gaze axis is computed from the second gaze axis and the first location using a first coordinate transformation.

Abstract: In an embodiment of the invention, a stereoscopic image of an object is obtained using two cameras. The locations and orientations of the two cameras are obtained. The stereoscopic image of the object is displayed on a stereoscopic display. A first gaze line from a right eye and a second gaze line from a left eye of an observer viewing the object on the stereoscopic display are measured. A location of the object in the stereoscopic image is calculated from an intersection of the first gaze line and the second gaze line. The three-dimensional location of an object is calculated from the locations and orientations of the two cameras and the location of the object in the stereoscopic image.

Abstract: An embodiment of the present invention is a system for identifying a user by observing irregularities on the surface of an eyeball of the user includes a topography system and a gaze tracking system. The topography system obtains one or more discernable features of the eyeball and stores the one or more discernable features. The gaze tracking system observes the irregularities, compares the irregularities to the one or more discernable features, and identifies the user if the irregularities and the one or more discernable features match.

Abstract: Embodiments of the present invention relate to systems and methods for minimizing motion clutter in image-generation devices. Temporally-interleaved image-subtraction reduces the magnitude of motion clutter and has no adverse effect on the desired ambient-light cancellation of static images. Embodiments of image-interleaved generation devices employing temporally-interleaved image-subtraction include single, double, triple, and series accumulator configurations. All four embodiments allow synchronization with scene illuminators and may be implemented on a single electronic chip. Temporally-interleaved image-subtraction is particularly well suited for use in video eyetracking applications where ambient light and scene motion can cause significant problems.

Abstract: Embodiments of the present invention relate to eyetracking methods and systems that compensate for physiological variations in the location of the pupil within the eye. In one embodiment, a video eyetracker measures the location of a pupil within the eye. Using measured observable features of the eye, including pupil diameter, a pupil-location-offset is estimated with respect to a fixed point on the eyeball. The location of a fixed point within the eyeball is estimated as a function of the measured pupil location and the estimated pupil-location-offset.

Abstract: Embodiments of the present invention relate to eyetracking methods and systems that compensate for physiological variations in the location of the pupil within the eye. In one embodiment, a video eyetracker measures the location of a pupil within the eye. Using measured observable features of the eye, including pupil diameter, a pupil-location-offset is estimated with respect to a fixed point on the eyeball. The location of a fixed point within the eyeball is estimated as a function of the measured pupil location and the estimated pupil-location-offset.

Abstract: In applications where it is desired to determine the locations of image features, such as eye monitoring to determine the direction that a person is gazing, determining the point at which he is gazing, or measuring the motions of his eye using a camera to capture an optical image of the eye and image processing to extract information about the eye's gaze point and/or orientation, there is provided a method and apparatus for precise location of image features such as edge coordinates between the pupil anc iris of the eye and of the center coordinates of light reflections off the cornea of the eye.

Abstract: It is sometimes required to track randomly moving objects with precision and high speed. This inventioin pertains to a mirro rotation assembly that provides precise, high-speed pitch and yaw tracking by rotating a low-moment-of-inertia mirror rather than rotating a heavier double gimballed mirror assembly or the camera-lens assembly itself. By pivoting the mirror on a single bearing point and controlling the mirror surface pitch and yaw by driving two mirror tie points along circumferential paths around the bearing point, a low moment of inertia is obtained. The low moment of inertia together with mirror velocity rather than position control permits higher speed tracking while maintaining the required precision. The velocity control strategy minimizes image blur resulting from unpredicted object motions.

Abstract: A system for focussing a lens on a point light source is provided that includes an opaque member disposed near the lens. The member cast a shadow having a distinguishable orientation in the image of the light source. An image processing device determines the focus condition and range to the point light source from the orientation and size of the shadow.

Abstract: A method and apparatus are disclosed for analyzing the dynamic resistance of a resistance spot welding process to determine the time of an expulsion event and use that time as the weld completion time for controlling weld termination via a weld feedback signal, controlling automatic current stepping, and identifying maintenance needs. A preconditioning pulse is used to stabilize the weld process and aid in obtaining interpretable resistance information. After an initial blanking period the resistance curve is analyzed by calculating first and second derivative values and applying several algorithms that make possible the computer recognition of characteristic resistance curve shapes resulting from weld expulsion under good geometry, bad geometry and edge weld conditions.

Abstract: During a weld period the weld parameters are monitored and data representing the weld resistance curve and the power curve are acquired and stored for analysis by a suitably programmed computer. The derivative of R, R is calculated and stored and the function is divided by power P to obtain R/P. The resistance curve is searched to obtain the maximum value R.sub.m which occurs during the heating phase and the function R/P is searched prior to the time of R.sub.m to find the maximum of that curve representing the highest rate of resistance increase. Then the R/P curve is searched subsequent to its maximum to determine when the function reaches a specified percentage of the maximum. That value occurs at the knee of the resistance curve and approximates the onset of melting in the weld.

Abstract: During a weld period the weld parameters are monitored and data representing the weld resistance curve and the power curve are acquired and stored for analysis by a suitably programmed computer. The derivative of R, R is calculated and stored and the function is divided by power P to obtain R/P. The resistance curve is searched to obtain the maximum value R.sub.m which occurs during the heating phase and the function R/P is searched prior to the time of R.sub.m to find the maximum of that curve representing the highest rate of resistance increase. Then the R/P curve is searched subsequent to its maximum to determine when the function reaches a specified percentage of the maximum. That value occurs at the knee of the resistance curve and approximates the onset of melting in the weld.

Abstract: During a weld period the weld parameters are monitored and data representing the weld resistance curve and the power curve are acquired and stored for analysis by a suitably programmed computer. The derivative of R, R is calculated and stored and the function is divided by power P to obtain R/P. The resistance curve is searched to obtain the maximum value R.sub.m which occurs during the heating phase and the function R/P is searched prior to the time of R.sub.m to find the maximum of that curve representing the highest rate of resistance increase. Then the R/P curve is searched subsequent to its maximum to determine when the function reaches a specified percentage of the maximum. That value occurs at the knee of the resistance curve and approximates the onset of melting in the weld.

Abstract: The disclosure relates to a self-organizing control of advanced turbine engines wherein thrust is controlled and thrust specific fuel consumption (TSFC) is minimized by control of the fuel flow rate as well as optimization of system geometric parameters. The controller computes the net thrust error by comparing commanded thrust with an inferred or calculated thrust measurement.

Abstract: A device for the total circumferential scanning of pipes and pipe joints is provided comprising a housing accommodating a tooth drive roller, drive means connected to said toothed drive roller, toothed idler rollers, a plurality of smooth idler rollers, scanning means for detecting faults and imperfections in pipes and pipe joints, and a flexible belt toothed on one surface thereof having a length greater than the circumference of the pipe to be scanned and having ends adapted to be securely joined together, said belt being adapted to be routed circumferentially around said pipe and through said housing by contacting each of said rollers whereby said belt is automatically aligned around said pipe so that said device circumferentially traverses the pipe in a plane perpendicular to the pipe axis.

Abstract: The disclosure relates to a non-minimum phase linear controller which uses positive servomechanism rate feedback to control hydraulic mechanisms. The disclosure also relates to a controller comprising, in combination, a conventional linear controller and a non-minimum phase linear controller, the outputs of the combined controllers being weighted in a predetermined ratio to provide a single output control signal.