Abstract: An integrated touch-sensing display is operated to detect the location of one or more objects on a touch surface. The integrated touch-sensing display defines a display area. A light guide (14) is arranged over the display area to define the touch surface (16). The light guide (14) is illuminated internally such that an object (20) contacting the touch surface (16) causes part of the illuminating light to be scattered towards the display area. An array of light sensors (6) is integrated within the display area to detect the scattered light. Based on output signals from the light sensors (6), a processing element obtains image data that represents the light that impinges on the display area excluding ambient light, and determines the location of the object (20) on the touch surface (16). Ambient light may be suppressed by a spectral passband filter in front of each light sensor (6), and/or by electronic filtering of the output signals from the sensors (6).

Abstract: Objects touching a surface portion attenuate transmitted signals. A data processor processes an output signal from a detector coupled to the outcoupling points, to generate a set of data samples indicative of detected energy for the actual detection lines. The set of data samples is further processed to generate a set of matched samples indicative of estimated detected energy for fictitious detection lines that extend across the surface portion in parallel groups at a plurality of different angles. The individual spacing between the fictitious detection lines in each group and the individual difference in angle between said groups are selected such that the set of matched samples transforms to Fourier coefficients arranged as data points on a pseudo-polar grid in a Fourier domain. The set of matched samples is processed by tomographic reconstruction to generate a two-dimensional distribution of an interaction parameter within the surface portion.

Abstract: Multi-touch sensitivity is enabled using a touch system that comprises a panel configured to conduct signals, e.g. by FTIR, from a plurality of incoupling points to a plurality of outcoupling points, thereby defining detection lines across the panel between pairs of incoupling and outcoupling points. A signal processor operates in a repeating sequence of iterations to obtain (50) a current signal value for each detection line, and generate (53, 53?) a first interaction pattern and a second interaction pattern as a function of the current signal values, such that the first and second interaction patterns are reconstructed two-dimensional distributions of local interaction with the conducted signals across the surface portion, and represent changes in interaction on different time scales. Thereby, the movement of an object will affect how it is represented in each of the first and second interaction patterns.

Abstract: A touch-sensitive apparatus comprises a panel configured to conduct signals from a plurality of peripheral incoupling points to a plurality of peripheral outcoupling points. Actual detection lines are defined between pairs of incoupling and outcoupling points to extend across a surface portion of the panel. The signals may be in the form of light, and objects touching the surface portion may affect the light via frustrated total internal reflection (FTIR). A signal generator is coupled to the incoupling points to generate the signals, and a signal detector is coupled to the outcoupling points to generate an output signal. A data processor operates on the output signal to enable identification of touching objects. The output signal is processed (40) to generate a set of data samples, which are indicative of detected energy for at least a subset of the actual detection lines.

Abstract: A touch-sensitive apparatus comprises a panel configured to conduct signals from a plurality of peripheral incoupling points to a plurality of peripheral outcoupling points. Actual detection lines are defined between pairs of incoupling and outcoupling points to extend across a surface portion of the panel. The signals may be in the form of light, and objects touching the surface portion may affect the light via frustrated total internal reflection (FTIR). A signal generator is coupled to the incoupling points to generate the signals, and a signal detector is coupled to the outcoupling points to generate an output signal. A data processor operates on the output signal to enable identification of touching objects. The output signal is processed (40) to generate a set of data samples, which are indicative of detected energy for at least a subset of the actual detection lines.

Abstract: A touch sensing apparatus includes a group of emitters arranged to emit light to illuminate at least part of the touch surface, a light detector arranged to receive light from the group of emitters, and a processing element. Each emitter is controlled to transmit a code by way of the emitted light such that the code identifies the respective emitter. 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. The processing element processes an output signal from the light detector to separate the light received from the individual emitters based on the transmitted codes, and to determine the position of the object/objects based on the light received from the individual emitters.

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: 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: A device for processing data from a touch sensitive apparatus is provided. The apparatus includes a light transmitting panel with a touch surface and an opposed back surface, an illumination arrangement configured to introduce light into the panel for propagation by internal reflection between the touch surface and the back surface, and a light detection arrangement configured to receive the light after propagation in the panel. A processor unit in the device obtains a monitored signal which is functionally dependent on transmitted light detected by the light detection arrangement; reconstructs, based on the monitored signal, a two-dimensional attenuation field representing an attenuation of the transmitted light on the touch surface; calculates an expected monitored signal based on the reconstructed attenuation field; and compares the expected monitored signal with the monitored signal in order to determine a reduced performance of the apparatus.

Abstract: A device implements a method of tracking objects on a touch surface of an FTIR based touch-sensitive apparatus. The method repeatedly operates to generate an interaction pattern that indicates local changes in interaction on the touch surface, identify apparent peaks in the interaction pattern, and update existing movement trajectories based on the apparent peaks. An error suppression process is executed at least intermittently in the method to process the apparent peaks and/or the existing movement trajectories to identify implicated trajectories with a potential tracking problem, define two or more movement propositions for each implicated trajectory, and cause an evaluation of the movement propositions in one or more subsequent repetitions of the method. The error suppression process improves tracking by postponing the final decision on how to track the object of the implicated trajectory until more information is available.

Abstract: Touch sensitivity is enabled using a touch system that comprises a panel configured to conduct signals, e.g. by TIR, from a plurality of incoupling points to a plurality of outcoupling points, thereby defining detection lines across a touch surface between pairs of incoupling and outcoupling points. A signal processor operates in a repeating sequence of iterations to: calculate change values for the detection lines representative of signal changes between the current and a previous iteration, and operate a reconstruction algorithm on the change values to determine a differential interaction pattern across the touch surface. The signal processor also operates to update a tracking pattern as a function of the differential interaction pattern, and generate a current offset pattern based on the tracking pattern. The offset pattern is generated to represent current touch interaction on the touch surface and is supplied for identification of touches on the surface portion.

Abstract: A multi-touch system includes a panel for conducting signals, e.g. by FTIR, from incoupling points to outcoupling points, to define detection lines across the panel. A signal processor operates in a repeating sequence of iterations to obtain an output signal from a detector coupled to the outcoupling points and generate a formatted signal value for each detection line, and operate a reconstruction algorithm on the formatted signal values to determine an interaction pattern on the panel. The signal processor also, at least intermittently in the sequence of iterations, operates compensation data on the formatted signal values to compensate for contaminations on the panel, and calculates updated compensation data based on an interference pattern determined as a function of the interaction pattern, the interference pattern being a 2D representation of contamination-induced signal interferences. The influence of contaminations in the interaction pattern is thereby suppressed.

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: Multi-touch sensitivity is enabled using a touch-sensitive apparatus comprising a panel for conducting signals from a plurality of incoupling points to a plurality of outcoupling points, thereby defining detection lines between pairs of incoupling and outcoupling points. Signal generators coupled to the incoupling points generate the signals, and signal detectors coupled to the outcoupling points generate an output signal indicative of one or more touches on the surface portion. A signal processor obtains the output signal which, if converted into a set of data samples of a given input format, enables a predetermined reconstruction algorithm to determine an interaction pattern on the surface portion. The signal processor generates, based on the output signal, a modified set of data samples in the given input format; and operates the predetermined reconstruction algorithm on the modified set of data samples so as to determine a modified interaction pattern on the surface portion.

Abstract: A touch-sensitive apparatus comprises a panel for conducting signals from incoupling points to outcoupling points. Actual detection lines are defined between pairs of incoupling and outcoupling points to extend across the panel. A signal generator is coupled to the incoupling points to generate the signals, e.g. light, and a signal detector is coupled to the outcoupling points to generate an output signal. A data processor processes the output signal to generate a set of data samples, which are non-uniformly arranged in a two-dimensional sample space. Each data sample is indicative of detected energy on a detection line and is defined by a signal value and first and second dimension values in the sample space. The first and second dimension values define the location of the detection line on the surface portion. Adjustment factors are obtained for the data samples, each adjustment factor being representative of the local density of data samples in the sample space.

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: A device obtains a signal representative of objects on a touch surface of a multi-touch sensing apparatus and executes a method for extracting touch data from the signal. The method operates in a sequence of detection frames. Each detection frame comprises the steps of: obtaining (300) the signal; processing (301) the signal for identifying touches; determining (302) a set of identified touches and touch data for the set of identified touches; and outputting (303) the touch data. At least one of the steps of processing (301) and determining (302) includes a prioritization that actively favors certain touches to be identified and included in the set of identified touches, respectively. Temporal prioritization favors a touch that corresponds to a previous touch, which is identified in one or more preceding detection frames. Spatial prioritization favors a touch that is located within at least one predefined subarea on the touch surface.

Abstract: A touch-sensitive apparatus comprises a panel configured to conduct signals from a plurality of peripheral incoupling points to a plurality of peripheral outcoupling points. Actual detection lines are defined between pairs of incoupling and outcoupling points to extend across a surface portion of the panel. The signals may be in the form of light, and objects touching the surface portion may affect the light via frustrated total internal reflection (FTIR). A signal generator is coupled to the incoupling points to generate the signals, and a signal detector is coupled to the out-coupling points to generate an output signal. A data processor operates on the output signal to enable identification of touching objects. The output signal is processed (40) to generate a set of data samples, which are indicative of detected energy for at least a subset of the actual detection lines.

Abstract: A touch-sensing apparatus is based on frustrated total internal reflection (FTIR). The apparatus comprises a panel, in which sheets of light are propagated by internal reflection between a touch surface and an opposite surface. A light sensor arrangement is optically connected to the panel to measure transmitted light energy on detection lines across the touch surface. Each detection line represents a light path across the touch surface from a light source to a light sensor. An object that touches the touch surface will frustrate the propagating light and cause a local attenuation among the detection lines. A data processor is connected to the light sensor arrangement and configured to execute a process for extracting touch-related data.

Abstract: A device is configured to process data from a touch-sensitive apparatus for the purpose of identifying a reduced performance of components in the apparatus. The apparatus may be an FTIR system that comprises a light transmissive panel, an illumination arrangement for introducing light into the panel, and a light detection arrangement for receiving the light propagating in the panel and for measuring the energy of the received light. The device comprises a processor unit which is configured to obtain a signal comprising a time series of signal values that represent the energy of the light received by the light detection arrangement; calculate a parameter value representing a temporal variability of the signal values in the signal; and identify, based on the parameter value, a reduced performance of any of the illumination arrangement and the light detection arrangement.