Abstract: A method for driving a lamp (2) comprises the steps of: generating a lamp current (ICONST) having a constant magnitude; defining a commutation period having a duration TCOMM; defining a time base of original commutation moments, having fixed mutual intervals of 0.5*TCOMM; receiving data to be embedded in the light output; commutating the lamp current at commutation moments; wherein individual commutations are time-modulated in order to encode said received data. Preferably, a commutation moment is: either equal to an original commutation moment if there are no data to embed; or advanced over a modulation distance (?) with respect to the corresponding original commutation moment in order to encode data having a first value (“0”); or delayed over said modulation distance (?) with respect to the corresponding original commutation moment in order to encode data having a second value (“1”).

Abstract: A method for driving a lamp (2) comprises the steps of: generating a lamp current (ICONST) having a constant magnitude; defining a commutation period having a duration TCOMM; defining a time base of original commutation moments, having fixed mutual intervals of 0.5*TCOMM; receiving data to be embedded in the light output; commutating the lamp current at commutation moments; wherein individual commutations are time-modulated in order to encode said received data. Preferably, a commutation moment is: either equal to an original commutation moment if there are no data to embed; or advanced over a modulation distance (?) with respect to the corresponding original commutation moment in order to encode data having a first value (“0”); or delayed over said modulation distance (?) with respect to the corresponding original commutation moment in order to encode data having a second value (“1”).

Abstract: Methods for exchanging signals via a network with nodes (11-15) improve the performance of the network by letting a destination node (12) s receive the signals originating from a source node (11) via different first and second signal routes, and by processing and correlating these signals in the destination node (12). In dependence of a correlation result, a process for processing a signal in a node (11-15) is adjusted. This process may be situated in the destination node (12), or in the source node (11) or an io intermediate node (13-15), in which case a control signal is to be exchanged. A learning algorithm for the adjusting of the process can be run in the nodes (11-15). Label switched routing can be introduced, whereby the label signal is sent from the source node (11) to the destination node via a third signal route different from the first and second signal route, to improve the efficiency of the nodes (11-15).

Abstract: This invention relates to a method for processing light in a structure, such as a room or a part thereof, a vehicle, etc., where several light sources are arranged in the structure. The light sources emit light carrying individual codes. A camera is arranged in a camera position of the structure and registers images of spots of the light. The spots can be, “for instance, illuminated areas of a floor or the direct light images of the light sources. The individual codes are derived from the registered images and one or more properties, such as for instance light source position or light intensity, related to the associated light source, is determined. The method is performed by means of a lighting system having several light sources, a camera, and a signal processing apparatus. Typical applications for the invention are light source commissioning and real time foot-print measurements.

Abstract: A vehicle position measurement system (100) and method to determine the (relative) position of a vehicle (110) and an object (120) are proposed. The system comprises at least two light sources (131, 132) capable of emitting light and positioned at a predetermined distance (140) to each other. Furthermore the system comprises at least one detector (150/151, 152) capable of measuring the light emitted. The light emitted by the light sources comprises synchronized light source identification codes. The detector is arranged to determine the position of the vehicle (110) and object (120) on the basis of a phase-difference measurement between the light originating from the individual light sources (131, 132) and a comparison phase. The vehicle (110) may comprise the at least two light sources (131, 132) and the detector (151, 152), while the phase-difference is measured between light reflected from the object (120) and the comparison phase.

Abstract: It is presented a method for transmitting lighting device data. The method comprises the steps of obtaining, in a lighting device, a subset of lighting device data, the lighting device data containg information of the lighting device, transmitting, from the lighting device, using light, the subset of lighting device data, and repeating the above steps until all subsets jointly corresponding to the complete lighting device data have been transmitted. A corresponding lighting device and lighting system are also presented.

Abstract: Proposed is an object localization method, system and user interface device for locating a (misplaced) object (10) in an area of a construction (1). The method comprises the steps of (i) identifying the object (10), (ii) providing an illumination device (20) comprising a plurality of light sources (30) modulated to emit light comprising light source identification codes (35), (iii) illuminating the tag (11) with light emitted by the light sources (30), (iv) requesting the tag (11) to measure the illumination and to identify the light sources (30) illuminating the tag by their light source identification codes (35), (v) transmitting object location data from the tag (11) relating to the measured illumination and light source identification codes (35) to a master controller (25) arranged to control the illumination device (20), (vi) providing a feedback signal related to the object (10) using the master controller (25).

Abstract: Methods for exchanging signals via a network with nodes (11-15) improve the performance of the network by letting a destination node (12) s receive the signals originating from a source node (11) via different first and second signal routes, and by processing and correlating these signals in the destination node (12). In dependence of a correlation result, a process for processing a signal in a node (11-15) is adjusted. This process may be situated in the destination node (12), or in the source node (11) or an io intermediate node (13-15), in which case a control signal is to be exchanged. A learning algorithm for the adjusting of the process can be run in the nodes (11-15). Label switched routing can be introduced, whereby the label signal is sent from the source node (11) to the destination node via a third signal route different from the first and second signal route, to improve the efficiency of the nodes (11-15).

Abstract: A device for imaging a turbid medium, for example a breast of a female, includes a holder for receiving the medium, a light source, a photodetector and a processing unit for deriving the image from the intensities measured. The holder is adapted to receive besides the turbid medium also an adaptation medium for influencing a photon path distribution of the turbid medium. The use of different values of optical parameters of the adaptation medium introduces different photon path distributions in the turbid medium. By means of these different photon path distributions the resolution of the image can be improved by utilizing the light sources and/or photodetectors in the same positions. When a liquid is used as the adaptation medium the shape of the adaptation medium can be perfectly matched between the holder and the turbid medium.

Abstract: A device for imaging a turbid medium, for example a breast of a female, includes a holder for receiving the turbid medium, a light source, a photodetector and a processing unit for deriving the image from the intensities measured. The holder is adapted to receive besides the turbid medium also an adaptation medium having substantial identical optical parameters as the optical parameters of the turbid medium. In this way artefacts in the reconstructed image due to the boundary effect between the turbid medium and the holder can be reduced. When a liquid is used as the adaptation medium a perfect match between the holder and the shape of the turbid medium can be obtained. Further, also intensity differences in the image due to different path lengths between light source and photodetector can be equalized.

Abstract: A method of imaging an interior of a turbid medium, for example a part of a breast of a human female, the turbid medium is irradiated with light and measurement of the intensity of light propagated along a plurality of light paths through the turbid medium is measured. An image of the interior of the turbid medium is reconstructed from the intensities measured. Furthermore, possible strengths assignable to each pixel of the image are determined from combinations of weighting functions and differences between expected photon fluences and a measured photon fluences from the intensities measured. A distribution function is made up from the possible strength determined. In a last step the image is determined from the distribution function. Further steps can be carried out to correct for objects of high strength in the image.

Abstract: A method and device of imaging an interior of a turbid medium is disclosed for reconstruction of biomedical images consecutive irradiation of the turbid medium with light from a light source from a plurality of positions and detection of the light propagated along a plurality of paths through the turbid medium. The method starts with a simple back-projection algorithm to get a first image. Then in next steps this image is corrected by deconvolution with a spatially varying convolution function. This convolution function is based on the scattering and coefficients of the turbid medium and the propagation of the light in the turbid medium. A second correction approach is obtained by means of a coordinate transformation. Advantages of the method according to the invention are that the method is rather easy to implement, the method needs only a few iteration steps to obtain corrected images and the method does not suffer from instability problems.

Abstract: Neural net with spatially distributed functionalities. An information processing system comprises a neural net with fully distributed neuron and synapse functionalities in a spatially inhomogeneous medium to propagate a response field from an input to an output. The response field is a reaction of the medium to a plurality of input signals and depends non-linearly on the input signals. The response field is also determined by the inhomogeneities. The value of the field at one or more particular locations is indicative of one or more output signals of the neural net.

Abstract: An optical information processing system comprises a coding unit for individually coding a plurality of optical information carrier waves, and a processing unit for processing the plurality of coded waves. The processing unit has a laser for producing laser light through longitudinal laser mode competition among the waves received.

Abstract: An information processing system comprises a neural net with fully distributed neuron and synapse functionalities in a spatially inhomogeneous medium to propagate a response field from an input to an output. The response field is a reaction of the medium to a plurality of input signals and depends non-linearly on the input signals. The response field is also determined by the inhomogeneities. The value of the field at one or more particular locations is indicative of one or more output signals of the neural net.

Abstract: An actively phase matched waveguide structure suitable for use as a frequency doubling device is described. The phase matching of the waveguide is controlled by application of a control voltage. The waveguide includes first and second non-linear optical layers of material having differing indexes of refraction forming a waveguide. Disposed on the surface of the waveguide is a layer of transparent semiconductor material disposed between two transparent electrodes. The index of refraction of the transparent semiconductor material varies with the potential applied to the electrode and thereby varies the phase matching of the waveguide as a whole.

Abstract: An actively phase matched waveguide structure suitable for use as a frequency doubling device is described. The device includes a non-linear optical waveguide and phase matching of the waveguide is controlled by an electrically operated light modulator which is spaced apart from the waveguide. The modulator includes one or more electrodes disposed on a substrate and an elastomeric transparent gel which has a metallic coating on its upper surface. Application of a voltage between the metallic upper surface and the electrodes causes a deformation in the gel which alters the gap between the upper surface of gel and thus provides phase matching.

Abstract: An active waveguide device is provided for doubling the frequency of an applied light wave. The device includes first and second optical waveguides which are coupled through a separating gap. The coupling can be precisely adjusted to maximize the doubling efficiency by adjusting the gap dimension. The device is particularly suitable for producing higher frequency blue radiation from lower frequency infrared radiation which is readily produced by semiconductor lasers.

Abstract: Wide band gap, single conductivity type semiconductor light emitting diodes (LED's) feature a bias potential across the device below that required for carrier multiplication by avalanche breakdown, together with separate means for carrier introduction, such as an electron beam of a pn junction diode, to achieve light emission. The addition of Fabry-Perot surfaces converts the LED to a semiconductor laser. Efficiency enhancing heterostructure, including potential wells and staircases, may be added to the device. Arrays of such devices on a substrate may be scanned by an electron beam to display video information.