Abstract: A circuit comprising a controller (2) for controlling a pulse width modulated input signal, and a driver (4) configured to supply current to a load (6) based on the input signal, wherein over the on time of each pulse width modulation period the driver (4) supplies current to the load (6) with a second frequency that is greater than the first frequency. The controller (2) is configured to control the duty cycle to set the output of the load (6) to a desired output level, and to dither the duty cycle about a point corresponding to the desired output level.

Abstract: There is provided a method for detecting modulated light comprising: receiving a set of images acquired by means of a rolling shutter camera having image acquisition settings comprising a frame rate, fframe, and a line rate, fline; identifying in consecutive frames of said images—a pattern governed by the ratio between a modulation frequency, fc, of a modulated light source and the line rate, fline, and—between consecutive frames a spatial shift of said pattern governed by the ratio between said modulation frequency fc, and said frame rate, fframe; and providing based on said pattern and spatial shift thereof, an estimate of the modulated light amplitude from said light source.

Abstract: According to one aspect of the disclosure, a lighting system comprises a remote control unit (4) and at least one lighting device (2a, 2b, 2c) comprising a light driver (13) and a light emitter (14). The remote control unit (4) comprises an image capturing unit (5) and is arranged to control the lighting device (2a, 2b, 2c). To do so, the remote control unit (4) receives information relating to current/present settings of the image capturing unit (5), then determines one or more properties of signals for visible light communications based on these settings. The one or more properties are then communicated to the at least one lighting device (2a, 2b, 2c). Upon reception thereof the light driver (13) generates a light emitting control signal based on the received properties and visible light communications based on the light emitting control signal is emitted by the light emitter (14).

Abstract: The present invention relates to a mobile device for detecting light. The mobile device (300) includes a photo detector (320) which is arranged at the end of a socket barrel (114) of an audio jack socket in the mobile device. The socket barrel serves to collimate the light onto the photo detector.

Abstract: A coded light component is modulated into emitted light on one of multiple channels each having a different modulation frequency. Modulation in the light causes a receiving camera to experience an apparent temporal frequency due to sequential capture of multiple frames and an apparent spatial frequency due to sequential exposure of spatial portions within each frame. Each channel can be detected by a detection module of the camera based on a respective combination of values of the apparent temporal and spatial frequency corresponding to the respective modulation frequency. The detection module has a respective response on each channel that varies as a function of the apparent temporal frequency. The channel for modulating the coded light component is selected from amongst a predetermined set having a property that the response of the detection module on each channel will have a minimum substantially at the apparent temporal frequency of each other channel.

Abstract: The possibility to emit and detect coded light, whereby data is modulated into the light, is known. According to one aspect of the present disclosure, to reduce the risk of the modulation going undetected due to possible frequency blind spots in the detection spectrum, the lighting device (2a, 2b, 2c) is arranged such that the frequency of its emitted modulated light (3a, 3b, 3c) shivers around a base, or center, frequency. For example the modulated light (3a, 3b, 3c) may be transmitted using pulse-width-modulation, and the resulting pulse-width-modulation light signal (3a, 3b, 3c) may thus have a period that fluctuates around the base period (T). The parameters determining the shivering of the modulated light (3a, 3b, 3c) may be chosen such that visible flicker in the emitted modulated light (3a, 3b, 3c) is avoided. According to another aspect, the lighting device (2a, 2b, 2c) emits with a plurality of different modulation frequencies simultaneously.

Abstract: A device comprising an input for receiving image data representing light captured by a camera, and an image analysis module for detecting a coded light component modulated into the light with a modulation frequency. The camera has an exposure time, and the light is captured over a sequence of exposures each lasting for an instance of the exposure time. The detection performed by the image analysis module experiences a frequency blind spot in said detection due to an effect of said exposure time. To address this issue, the device further comprises an output for controlling one or more parameters of the camera which affect the exposure time, and a controller configured to control the one or more parameters to avoid that the modulation frequency corresponds to the frequency blind spot.

Abstract: A method for calibrating an ambience lighting system for providing an ambient light effect for a cinema display screen is proposed. The method is based on implementing the ambience lighting system in the form of one or more of coded light (CL) sources. The method then includes processing one or more images of a scene being illuminated by the ambience lighting system to determine, based on the CL embedded into the light output of the individual CL sources, color and/or an intensity of the light generated by the individual CL source. The set of control data for controlling the CL sources to provide the desired ambient light effect is then based not only on the color and/or intensity of image content to be displayed on the cinema display screen, but also on the determined color and/or intensity of the light output of the individual CL sources.

Abstract: The invention provides a communication system (500), a lighting system, a method of transmitting information and a computer program product. The communication system according to the invention is configured for transmitting data via visible light. The communication system comprises a signal generator (530) for generating a light driving signal (200) being a frequency shift key modulated signal comprising a sequence of signal parts (215, 225), each signal part being modulated at a first or second frequency in accordance with the data, the signal parts modulated at the first frequency having first pulses in first periods (T0) and the signal parts modulated at the second frequency having second pulses in second periods (T1). Energy of the visible light corresponding to a pulse in a respective period has center of gravity in time.

Abstract: A method of controlling a light source (105) via a handheld computing device (110) is disclosed. The method comprises receiving an input produced by one or more sensors of the handheld computing device, the input being indicative of a current orientation of the handheld computing device. The method further comprises determining, based at least in part on the input, that the handheld computing device is in a predefined triggering orientation, e.g. in a generally horizontal orientation. In response to so determining, one or more frames of image data are acquired via an image sensor connected to the handheld computing device (110). The method further comprises obtaining an identifier of the light source, e.g. from information encoded into light emitted by the light source (105), having determined that the one or more frames of image data comprise image data representative of the light source (105).

Abstract: The invention relates to a method for enabling a user to control coded light (CL) sources. The method is performed after obtaining one or more images of a scene being illuminated by at least one CL source, the image of the CL source being present within the acquired image(s). The method includes processing the acquired image(s) to determine, based on the code embedded into the light output of the CL source, that the light output of that source is present within the scene, processing the acquired image(s) to determine the location of the image of the CL source within the acquired image(s), providing a user interface illustrating the scene, and providing a control icon within the user interface, the icon indicating to a user, based on the determined location of the CL source, that the icon is adapted to control the CL source.

Abstract: There is provided a method for detecting modulated light comprising: receiving a set of images acquired by means of a rolling shutter camera having image acquisition settings comprising a frame rate, fframe, and a line rate, fline; identifying in consecutive frames of said images—a pattern governed by the ratio between a modulation frequency, fc, of a modulated light source and the line rate, fline, and—between consecutive frames a spatial shift of said pattern governed by the ratio between said modulation frequency fc, and said frame rate, fframe; and providing based on said pattern and spatial shift thereof, an estimate of the modulated light amplitude from said light source.

Abstract: The possibility to emit and detect coded light, whereby data is modulated into the light, is known. According to one aspect of the present disclosure, to reduce the risk of the modulation going undetected due to possible frequency blind spots in the detection spectrum, the lighting device (2a, 2b, 2c) is arranged such that the frequency of its emitted modulated light (3a, 3b, 3c) shivers around a base, or center, frequency. For example the modulated light (3a, 3b, 3c) may be transmitted using pulse-width-modulation, and the resulting pulse-width-modulation light signal (3a, 3b, 3c) may thus have a period that fluctuates around the base period (T). The parameters determining the shivering of the modulated light (3a, 3b, 3c) may be chosen such that visible flicker in the emitted modulated light (3a, 3b, 3c) is avoided. According to another aspect, the lighting device (2a, 2b, 2c) emits with a plurality of different modulation frequencies simultaneously.

Abstract: According to one aspect of the disclosure, a lighting system comprises a remote control unit (4) and at least one lighting device (2a, 2b, 2c) comprising a light driver (13) and a light emitter (14). The remote control unit (4) comprises an image capturing unit (5) and is arranged to control the lighting device (2a, 2b, 2c). To do so, the remote control unit (4) receives information relating to current/present settings of the image capturing unit (5), then determines one or more properties of signals for visible light communications based on these settings. The one or more properties are then communicated to the at least one lighting device (2a, 2b, 2c). Upon reception thereof the light driver (13) generates a light emitting control signal based on the received properties and visible light communications based on the light emitting control signal is emitted by the light emitter (14).