Abstract: A touch-sensing apparatus comprises a light transmissive panel, in which sheets of light are propagated by internal reflection between a touch surface and an opposite surface from an incoupling site to an outcoupling site. The touch-sensing apparatus is configured such that objects touching the touch surface cause a local attenuation of at least two sheets of light. A light sensor arrangement is optically connected to the outcoupling site to measure transmitted light energy. A data processor is connected to the light sensor arrangement and configured to execute a touch determination process. The process operates on at least one projection signal which is indicative of a spatial distribution of light within the outcoupling site.

Abstract: An apparatus for determining an interaction between an object and a touch surface of a panel. An illumination arrangement introduces light into the panel for propagation by internal reflection between the touch surface and an opposite surface and towards a receiving light detection arrangement. A processor unit is configured to iteratively i) determine, based on the received light, a current light status representing a two-dimensional distribution of light in the panel, ii) determine the interaction with the object as a function of the current light status and a previously updated background status representing a two-dimensional distribution of light in the panel caused by contaminations, and iii) update the background status as a function of the interaction. A method and computer readable medium are also described.

Abstract: An apparatus for determining a location of at least one object on a touch surface, comprising: a light transmissive panel defining the touch surface and including a controllable reflective boundary; an illumination arrangement configured to introduce light into the panel; a control device configured to selectively control the reflective boundary such that the light may pass between a first layer and a second layer via an opening in the reflective boundary; a light detection arrangement configured to measure the light passed via the opening and impinged on the touch surface; and a processor unit configured to determine the location as a function of the measured light passed via the opening and the selective control of the reflective boundary. A method and computer readable medium is also described.

Abstract: A touch-sensitive system comprises a light transmissive panel defining a touch surface and an opposite surface; an illumination arrangement comprising emitters configured to introduce light into the panel for propagation in the panel in an emission pattern; a light detection arrangement comprising detectors configured to receive the light propagating in the panel. A control unit is arranged to control the operation of the touch-sensitive system. The control unit executes a control method to monitor the light received in the light detecting arrangement for detection of touches on the touch surface, the touches attenuating the light propagating in the panel. The control method also selects a mode for the emission pattern in dependence of the occurrence of touches on the touch surface and controls the emission pattern in accordance with the selected mode.

Abstract: An apparatus, method and computer-readable medium for determining a location of at least one object on a touch surface of a light transmissive panel. The method comprises the steps of: introducing light into the panel for propagation by internal reflection between the touch surface and an opposite surface; receiving the light propagating in the panel; and iteratively i) determining a current signal profile of light received by the light detection arrangement, ii) updating, when a condition is met, a background signal profile of light received by the light detection arrangement, iii) calculating a current compensated signal profile as a function of the background signal profile and the current signal profile and iv) determining, when the object touches the touch surface and thereby attenuates the light propagating in the panel, the location as a function of the compensated signal profile.

Abstract: An apparatus is operated to determine the location of at least one object on a touch surface (4) of a light transmissive panel (1). In the apparatus, an illumination arrangement (2, 10) generates a first set of sheets (C1-C3) of light and introduces the first set of sheets (C1-C3) via a first elongate incoupling site on the panel (1) such that the first set of sheets (C1-C3) propagate by internal reflection between the touch surface (4) and an opposite surface. At least two sheets in the first set of sheets (C1-C3) are introduced so as to overlap in a portion of the touch surface (4) such that the object interacts with the at least two sheets. Typically, each sheet (C1-C3) in the first set is essentially collimated in the plane of the panel (1) along a respective main direction.

Abstract: A touch sensing apparatus is controlled to determine the position of one or more objects (7) that interact with a touch surface (1). The apparatus includes a group of emitters (2) arranged to emit light to illuminate at least part of the touch surface (1), a light detector (4) arranged to receive light from the group of emitters (2), and a processing element (7). Each emitter (2) is controlled to transmit a code by way of the emitted light such that the code identifies the respective emitter (2). The codes may at least partly be transmitted concurrently. The codes may be selected such that a value of an autocorrelation of each code is significantly higher than a value of a cross-correlation between any two codes of different emitters (2).

Abstract: An apparatus is operated to determine a location of at least one object on a touch surface of a light transmissive panel. An illumination arrangement in the apparatus is operated to introduce beams of radiation into the panel for propagation by internal reflection between the touch surface and the opposite surface, and to sweep each beam along the touch surface within a sensing area. Thereby, the sensing area is illuminated such that an object that touches the touch surface within the sensing area causes at least two beams to be temporarily attenuated. The illumination arrangement is arranged such that each beam, downstream of the sensing area, is swept along one or more elongate outcoupling sites on the panel. At least one light sensor, which is optically coupled to the outcoupling site, is operated to measure the received energy of the beam within the outcoupling site.

Abstract: A device operates on output signals from a light sensor arrangement in a touch-sensing apparatus to determine a position of an object on a touch surface. The apparatus includes a light transmissive panel that defines the touch surface and an opposite surface. A light source arrangement provides sheets of light inside the panel, wherein each sheet comprises light that propagates by internal reflection between the touch surface and the opposite surface from one or more incoupling points to a set of outcoupling points. The light sensor arrangement generates the output signals, which represent light reaching the outcoupling points. The apparatus is configured such that an object touching the touch surface locally attenuates at least two sheets of light. To determine the position, the device identifies, in the output signals, a set of signal profiles originating from said object.

Abstract: An apparatus is operated to determine the location of at least one object on a touch surface of a light transmissive panel. In the apparatus, an illumination arrangement introduces radiation into the panel for propagation by internal reflection between the touch surface and the opposite surface, so as to generate a grid of intersecting radiation paths in a sensing area, and a detection arrangement measures the transmitted energy in the radiation paths. A data processor then determines, based on the transmitted energy, the location based on an attenuation of two or more radiation paths caused by the object touching the touch surface within the sensing area. In the apparatus, the illumination arrangement generates at least a subset of the radiation paths by sweeping at least one beam of radiation along the touch surface.

Abstract: An apparatus is controlled to detect locations of a plurality of objects on a touch surface of a panel. An input scanner arrangement introduces at least three beams of radiation into the panel for propagation by internal reflection, and sweeps the beams inside the panel across a sensing area, preferably in at least two different principal directions. At least one radiation detector is arranged to receive the beams from the input scanner arrangement while they are swept across the sensing area. A data processor is connected to the radiation detector(s) and operated to identify the locations based on an attenuation of the beams caused by the objects touching the touch surface within the sensing area, the attenuation being identifiable from an output signal of the radiation detector(s). Each output signal may be further processed to generate a transmission signal, by dividing the output signal by a background signal which represents the output signal without any object on the touch surface.

Abstract: Automated localization of a point source of a visualized gas leak, by searching in a corner response function crƒ(x*,y*,?), calculated based on a number of frames of the gas leak, for maximum values in the (x*,y*) variables that are stable over the time variable ?. Considering a point (x*,y*) as the point source if the corner response function crƒ(x*,y*,?) has a maximum value in the point (x*,y*) and the point (x*,y*) is temporally stable.

Abstract: Automated localization of a point source of a visualized gas leak, by searching in a corner response function crf(x*,y*,?), calculated based on a number of frames of said gas leak, for maximum values in the (x*,y*) variables that are stable over the time variable ?. Considering a point (x*,y*) as said point source if said corner response function crf(x*,y*,?) has a maximum value in said point (x*,y*) and said point (x*,y*) is temporally stable.