Abstract: A back-lit screen comprising: a rigid frame extending around the periphery of the screen and having a front face, the front face having an interior face which defines an opening, and an outer face which defines the exterior contour of the frame transversely to the opening; and a translucent sheet extending across the opening; the frame being configured so that over at least a part of the periphery of the screen the forward-most part of the interior face is coincident with the exterior contour of the frame.

Abstract: A display controller configured to cause a display to show successive frames of a main presentation and to intermittently display a predetermined map of indicia between the frames of the main presentation, whereby a device can determine its location.

Abstract: A method for forming a processed video stream, comprising: capturing a first part of an input video stream using a camera; transmitting the first part of the video stream to a processing facility remote from the camera; at the processing facility, designating a first sub-region of the first part of the video stream for further processing; in dependence on the designation of a first sub-region, forming a first cropped video stream by cropping the first part of the video stream to that sub-region; forming the processed video stream incorporating the first cropped video stream.

Abstract: A system for capturing a video stream, the system comprising: a camera; and an encoding device configured to store video captured by the camera together with metadata indicating a location in the video at which a predesignated substitution object appears.

Abstract: A motion tracking system for tracking the motion of a subject in an environment, the system comprising: an imaging device adapted to be worn by the subject; an accelerometer adapted to be worn by the subject; and a processor configured to receive a series of images of the environment captured by the imaging device and to form, in dependence on the images an estimate of the subject's position in the environment, and to receive acceleration data from the accelerometer and to, form an estimate of the motion of a part of the subject's body carrying the accelerometer in dependence on the acceleration data and the estimated position.

Abstract: A lens calibration system for calibrating a lens of an image capture device, the lens calibration system comprising: a processor configured to receive from the image capture device a series of image frames of a scene at different rotational positions of the image capture device; The processor being configured to: Identify in the series of image frames elements representing a first marker located at a first known distance from the image capture device and a second marker located at a second known distance from the image capture device, the first and the second known distances being different to one another; track the identified elements representing each marker across the series of image frames; process the tracked elements to determine a characteristic parameter of the lens of the image capture device; and build a lens model for the image capture device in dependence on the determined characteristic parameter of the lens.

Abstract: A method for forming a processed video stream, comprising: capturing a first part of an input video stream using a camera; transmitting the first part of the video stream to a processing facility remote from the camera; at the processing facility, designating a first sub-region of the first part of the video stream for further processing; in dependence on the designation of a first sub-region, forming a first cropped video stream by cropping the first part of the video stream to that sub-region; forming the processed video stream incorporating the first cropped video stream.

Abstract: A motion tracking system configured to determine a rendering of a simulation object representing a real object (1) in a real environment (5, 6, 7, 8, 9), the positioning system comprising: an imaging device (24) mounted to the real object and configured to capture a series of images of a plurality of irregularly positioned markers (30) located in the real environment; an image processing unit communicatively coupled to the imaging device for receiving the series of images; the image processing unit being configured to determine the real location of the real object by: creating a three-dimensional model of a constellation formed by the markers visible in the series of images; and mapping the patterns of markers visible in successive images captured by the imaging device to the model and thereby determining the motion of the imaging device relative to the markers; and to determine the rendering of the simulation object so that the rendering mimics the determined motion of the imaging device.

Abstract: A method for monitoring a work process in which a workpiece is worked on by a tool, the method comprising: providing an irregular pattern of indicia remote from the workpiece and the tool; imaging the indicia by an imaging device carried by the workpiece and thereby estimating the location of the workpiece with respect to the indicia; imaging the indicia by an imaging device carried by the tool and thereby estimating the location of the tool with respect to the indicia; and correlating the location of the workpiece and the tool to estimate an operation performed by the tool on the workpiece.

Abstract: A method for forming augmented image data, the method comprising: forming a primary image feed showing a subject illuminated by a lighting unit; estimating the location of the lighting unit; receiving overlay data defining an overlay of three-dimensional appearance; rendering the overlay data in dependence on the estimated location to form an augmentation image feed; and overlaying the augmentation image feed on the primary image feed to form a secondary image feed.

Abstract: A method for forming augmented image data, the method comprising: forming a primary image feed showing a subject illuminated by a lighting unit; estimating the location of the lighting unit; receiving overlay data defining an overlay of three-dimensional appearance; rendering the overlay data in dependence on the estimated location to form an augmentation image feed; and overlaying the augmentation image feed on the primary image feed to form a secondary image feed.

Abstract: A method for automatically moving a vessel along a desired path, the method comprising: providing an irregular pattern of indicia remote from the vessel; imaging the indicia by an imaging device carried by the vessel and thereby estimating the location and orientation of the vessel with respect to the indicia; driving the vessel in dependence on the estimated location and orientation in order to cause the vessel to move along the path.

Abstract: A method for monitoring a work process in which a workpiece is worked on by a tool, the method comprising: providing an irregular pattern of indicia remote from the workpiece and the tool; imaging the indicia by an imaging device carried by the workpiece and thereby estimating the location of the workpiece with respect to the indicia; imaging the indicia by an imaging device carried by the tool and thereby estimating the location of the tool with respect to the indicia; and correlating the location of the workpiece and the tool to estimate an operation performed by the tool on the workpiece.

Abstract: A motion tracking system for tracking the motion of a subject in an environment, the system comprising: an imaging device adapted to be worn by the subject; an accelerometer adapted to be worn by the subject; and a processor configured to receive a series of images of the environment captured by the imaging device and to form, in dependence on the images an estimate of the subject's position in the environment, and to receive acceleration data from the accelerometer and to, form an estimate of the motion of a part of the subject's body carrying the accelerometer in dependence on the acceleration data and the estimated position.

Abstract: A motion tracking system configured to determine a rendering of a simulation object representing a real object (1) in a real environment (5, 6, 7, 8, 9), the positioning system comprising: an imaging device (24) mounted to the real object and configured to capture a series of images of a plurality of irregularly positioned markers (30) located in the real environment; an image processing unit communicatively coupled to the imaging device for receiving the series of images; the image processing unit being configured to determine the real location of the real object by: creating a three-dimensional model of a constellation formed by the markers visible in the series of images; and mapping the patterns of markers visible in successive images captured by the imaging device to the model and thereby determining the motion of the imaging device relative to the markers; and to determine the rendering of the simulation object so that the rendering mimics the determined motion of the imaging device.

Abstract: An optical navigation system comprising a camera oriented to face towards a plurality of markers located at spaced apart locations from the camera, calculating means adapted to calculate an angle subtended between pairs of markers, the subtended angles being calculated by monitoring the pixel locations of the markers in a series of images captured by the camera, the optical navigation system additionally comprising means for creating a three-dimensional model whereby the location of the camera relative to the markers is determined by triangulating the subtended angles in the three-dimensional model.

Abstract: An optical navigation system comprising a camera oriented to face towards a plurality of markers located at spaced apart locations from the camera, calculating means adapted to calculate an angle subtended between pairs of markers, the subtended angles being calculated by monitoring the pixel locations of the markers in a series of images captured by the camera, the optical navigation system additionally comprising means for creating a three-dimensional model whereby the location of the camera relative to the markers is determined by triangulating the subtended angles in the three-dimensional model.

Abstract: An optical navigation system comprising a camera oriented to face towards a plurality of markers located at spaced apart locations from the camera, calculating means adapted to calculate an angle subtended between pairs of markers, the subtended angles being calculated by monitoring the pixel locations of the markers in a series of images captured by the camera, the optical navigation system additionally comprising means for creating a three-dimensional model whereby the location of the camera relative to the markers is determined by triangulating the subtended angles in the three-dimensional model.

Abstract: A geared drive assembly (10) comprising the driven gear (12) arranged to mesh with the driving gear (14) and a rotary actuator operatively connected to the driving gear (14) by the pulley belt (22) engaging with an first pulley wheel (18) of the rotary actuator and a second pulley wheel (24) rigidly and coaxially connected to the driving gear (14), wherein the pulley belt (22) comprises first (26) and second (28) pulley belt portions extending between the first (18) and second (24) pulley wheels, wherein the first pulley belt portion (26) is maintained, in use, under tension, and wherein the second pulley belt portion (28) is slack, in use. Advantages of the invention, compared with known anti-backlash gearboxes, include: significant weight reductions, reduced complexity, reduced drag, smaller motor sizes, reduced part count, reduced play and backlash.

Abstract: A geared drive assembly (10) comprising the driven gear (12) arranged to mesh with the driving gear (14) and a rotary actuator operatively connected to the driving gear (14) by the pulley belt (22) engaging with an first pulley wheel (18) of the rotary actuator and a second pulley wheel (24) rigidly and coaxially connected to the driving gear (14), wherein the pulley belt (22) comprises first (26) and second (28) pulley belt portions extending between the first (18) and second (24) pulley wheels, wherein the first pulley belt portion (26) is maintained, in use, under tension, and wherein the second pulley belt portion (28) is slack, in use. Advantages of the invention, compared with known anti-backlash gearboxes, include: significant weight reductions, reduced complexity, reduced drag, smaller motor sizes, reduced part count, reduced play and backlash.