Abstract: A personal computer system includes a visual display, an imaging device adapted to provide eye-tracking data by imaging the face of a viewer of the visual display, and an input device for accepting eye-tracking control data and other input data. The imaging device is switchable between at least an active mode, a ready mode and an idle mode, and the switching time from the idle mode to the active mode is longer than the switching time from the ready mode to the active mode. The eye-tracking data provided in the ready mode may include eye position but not eye orientation. The system may include a dedicated input device for forcing the imaging device into active mode by directly triggering an interrupt; alternatively, the dedicated input device forces it permanently into idle mode.

Abstract: An eye tracker includes at least one illuminator for illuminating an eye, at least two cameras for imaging the eye, and a controller. The configuration of the reference illuminator(s) and cameras is such that, at least one camera is coaxial with a reference illuminator and at least one camera is non-coaxial with a reference illuminator. The controller is adapted to select one of the cameras to be active to maximize an image quality metric and avoid obscuring objects. The eye tracker is operable in a dual-camera mode to improve accuracy. A method and computer-program product for selecting a combination of an active reference illuminator from a number of reference illuminators, and an active camera from a plurality of cameras are provided.

Abstract: A computer apparatus is associated with a graphical display presenting at least one GUI-component adapted to be manipulated based on user-generated commands. An event engine is adapted to receive an eye-tracking data signal that describes a user's point of regard on the display. Based on the signal, the event engine produces a set of non-cursor controlling event output signals, which influence the at least one GUI-component. Each non-cursor controlling event output signal describes a particular aspect of the user's ocular activity in respect of the display. Initially, the event engine receives a control signal request from each of the at least one GUI-component. The control signal request defines a sub-set of the set of non-cursor controlling event output signals which is required by the particular GUI-component. The event engine delivers non-cursor controlling event output signals to the at least one GUI-component in accordance with each respective control signal request.

Abstract: The present invention relates to automatic registration and tracking of the eyes of at least one subject. An optical system, including a lens structure, a mask and an image sensor, receives incoming light from a scene containing the subject and directs at least a portion of this light towards the image sensor, which registers spatially distributed light and thus produces primary data. The mask is to alter a basic optical transfer function of the lens structure and the image sensor into an enhanced optical transfer function, which is substantially less sensitive to variations of an unknown distance between the optical system and the subject than the basic optical transfer function. The processing unit is to receive the primary data and process this data to produce resulting eye-tracking data representing a position estimate of the at least one eye and/or a gaze direction for the at least one eye.

Abstract: An eye tracker includes at least one illuminator for illuminating an eye, at least two cameras for imaging the eye, and a controller. The configuration of the reference illuminator(s) and cameras is such that, at least one camera is coaxial with a reference illuminator and at least one camera is non-coaxial with a reference illuminator. The controller is adapted to select one of the cameras to be active to maximize an image quality metric and avoid obscuring objects. The eye tracker is operable in a dual-camera mode to improve accuracy. A method and computer-program product for selecting a combination of an active reference illuminator from a number of reference illuminators, and an active camera from a plurality of cameras are provided.

Abstract: For measuring the surface tension between a liquid and fluid such as a gas, a capillary (3, 3?) is used in which the liquid slowly flows and at the end of which drops (11) are formed, falling off into a closed space (7) containing the fluid. Using a pressure sensor (5, 5?) the pressure is measured which can be the absolute pressure of a fluid volume enclosed in the closed space or alternatively a differential pressure measured as the pressure difference between the liquid in the capillary and fluid contained in the closed space. The pressure is measured when one or more drops are formed and full off. The obtained pressure curves are evaluated electronically (12) and provide a value of the surface tension. The measurement can be made within a fairly short time with a high operational reliability. The temperature difference between the drop and the surrounding fluid is small resulting in a little precipitation of salts dissolved in the liquid, reducing the risk that the liquid capillary with be blocked.