Abstract: A time of flight sensor has an image region and a storage region on a device which may be a CCD. A pulse of light illuminates an object, and an image illumination stripe is recorded on the image region. In a distance determining step, the image region is clocked after emitting the pulse of light and the row in which the image illumination stripe is illuminated gives a measure of the distance to the object. The apparatus can self calibrated by emitting a pulse of light without clocking the image region.

Abstract: A time of flight sensor has a photosensitive image region (1) comprising a linear array of M pixels; a storage region (2) comprising M columns of N storage elements, and transfer circuitry to transfer data along the M columns of storage from an input storage element connected to a respective one of the M pixels along column of N storage elements to an output storage element at a transfer frequency Ft, each row of M storage elements storing data captured at the same time; and a readout section (3) arranged to read out data from the output end of the M columns of the storage region at a readout frequency Fr. In this way the readout frequency and transfer frequency may be separately controlled. An amplifier (4) may be connected to the readout section. An optical shield (5) may shield the storage elements leaving the photosensitive image region unshielded. The elements may be elements of a charge coupled array.

Abstract: A time of flight distance measurement system has a light emitter (8) emitting a pulsed fan beam and a time of flight sensor (6) which may be a CCD with a photosensitive image region, a storage region not responsive to light and a readout section. Circuitry is arranged to control the time of flight sensor (6) to capture image data of the pulsed illumination stripe along a row of pixels and to transfer the captured image data to the storage section. The circuitry adjusts the phase of the clocking of the image region with respect to the emission of a pulsed fan beam to collect a plurality of image illumination stripes at a respective plurality of phase shifts; and a processor combines the data from the plurality of image illumination stripes at the plurality of phase shifts to determine the distance to the object.

Abstract: A time of flight sensor has an image region (8) and a storage region (10) on a device which may be a CCD. A pulse of light illuminates an object, and an image illumination stripe is recorded on the image region. In a distance determining step, the image region is clocked after emitting the pulse of light and the row in which the image illumination stripe is illuminated gives a measure of the distance to the object. The apparatus can self calibrate by emitting a pulse of light without clocking the image region.

Abstract: A time of flight sensor has a photo-sensitive image region (1) comprising a linear array of M pixels; a storage region (2) comprising M columns of N storage elements, and transfer circuitry to transfer data along the M columns of storage from an input storage element connected to a respective one of the M pixels along column of N storage elements to an output storage element at a transfer frequency Ft, each row of M storage elements storing data captured at the same time; and a readout section (3) arranged to read out data from the output end of the M columns of the storage region at a readout frequency Fr. In this way the readout frequency and transfer frequency may be separately controlled. An amplifier (4) may be connected to the readout section. An optical shield (5) may shield the storage elements leaving the photosensitive image region unshielded. The elements may be elements of a charge coupled array.

Abstract: An intruder detection system comprises an illumination means for illuminating a field of view with a modulated optical signal, modulated by a modulation signal; an optical receiver for receiving a delayed reflected signal; a cross correlator for calculating a cross correlation function between the modulation signal and the received delayed reflected signal; and means for detecting changes in the cross correlation function, a change being used to provide intruder detection. This system uses optical sensing and cross correlation calculation to enable an intruder detection signal to be obtained. This can enable a solid state, low cost, and reliable sensor to be provided for detecting intruders.

Abstract: A digital solar compass has a planar image sensor (5) for capturing an image of a gnomon (1) perpendicular to the plane of the image sensor. A cover (12) protects the gnomon and image sensor. A signal processor (14) is arranged to determine the angle of a shadow cast by the sun and the gnomon from the image captured by the planar image sensor. The gnomon (1) may be mounted directly on the planar image sensor (5) or the shadow may be formed on a diffuser sheet (3) and projected onto the image sensor (5) using a lens (4).

Abstract: Optical correlators are discussed, suitable for in-vehicle distance measurement. The correlators use modulation sequences based on maximal length sequences. A number of different modulation sequences are obtained by generator (32) from a single maximal length sequence, either by adding a variable number of cycles to the end of the maximal length sequence or by starting the maximal length sequence at different points in the sequence.

Abstract: An imaging system has a transmission system (2) for transmitting a modulated optical signal and a reception system (3) for receiving a received optical signal which is a reflected and delayed version of the transmitted signal. The reception system includes a controllable shutter arrangement for allowing reception in a controllable time window. A memory (4) collects reception data derived from different time windows, and a measure of distance is obtained corresponding to a maximum correlation between the received optical signal and the timing of the controllable time window. Surface profile information is derived from multiple distance measurements. The shutter arrangement enables the distance measurement (and the subsequent profile calculation) to be free from noise from other scattering sources.

Abstract: An intruder detection system comprises an illumination means for illuminating a field of view with a modulated optical signal, modulated by a modulation signal; an optical receiver for receiving a delayed reflected signal; a cross correlator for calculating a cross correlation function between the modulation signal and the received delayed reflected signal; and means for detecting changes in the cross correlation function, a change being used to provide intruder detection. This system uses optical sensing and cross correlation calculation to enable an intruder detection signal to be obtained. This can enable a solid state, low cost, and reliable sensor to be provided for detecting intruders.

Abstract: An imaging system has a transmission system (2) for transmitting a modulated optical signal and a reception system (3) for receiving a received optical signal which is a reflected and delayed version of the transmitted signal. The reception system includes a controllable shutter arrangement for allowing reception in a controllable time window. A memory (4) collects reception data derived from different time windows, and a measure of distance is obtained corresponding to a maximum correlation between the received optical signal and the timing of the controllable time window. Surface profile information is derived from multiple distance measurements. The shutter arrangement enables the distance measurement (and the subsequent profile calculation) to be free from noise from other scattering sources.

Abstract: A vehicle safety system comprises a collision avoidance system, comprising range finding apparatus for determining a distance to an adjacent vehicle, the collision avoidance system comprising a transmitter (74) and a receiver (70). A communications system is used for communicating with a road side terminal. The communications system uses the same transmitter and receiver respectively to send and receive data to and from the road side terminal.

Abstract: Optical correlators are discussed, suitable for in-vehicle distance measurement. The correlators use modulation sequences based on maximal length sequences. A number of different modulation sequences are obtained by generator (32) from a single maximal length sequence, either by adding a variable number of cycles to the end of the maximal length sequence or by starting the maximal length sequence at different points in the sequence.

Abstract: An Image analysis system uses a multiple-region light detector for detecting light received from the receiving optics, wherein different regions of the light detector can be actuated separately. Control electronics synchronises the timing and direction of illumination of the light source and the actuation of the light detector. The time of light of light signals from the light source to the actuated portion of the detector for all illuminated directions is measured, and distances are derived. A warning is generated if the derived distance is less than a predetermined threshold.

Abstract: An imaging system scans a light source output over an object to be imaged, and receives the reflected signal in a multi-region light detector, wherein different regions of the object to be imaged are imaged onto different regions of the detector by the receiving optics, and wherein different regions of the light detector can be actuated separately. The light source scanning is synchronized with the actuation of the light detector so that a region of the detector imaging the region of object being illuminated by the light source is actuated. The time of flight of light signals from the light source to the actuated portion of the detector is calculated for all scanning directions, to enable a three dimensional image of the object to be constructed.

Abstract: An Image analysis system uses a multiple-region light detector for detecting light received from the receiving optics, wherein different regions of the light detector can be actuated separately. Control electronics synchronises the timing and direction of illumination of the light source and the actuation of the light detector. The time of light of light signals from the light source to the actuated portion of the detector for all illuminated directions is measured, and distances are derived. A warning is generated if the derived distance is less than a predetermined threshold.

Abstract: In imaging apparatus particularly for use in intra-oral dental applications, a solid state imager is continually clocked out during a wait period prior to irradiation from an X-ray source. A signal derived from the CCD is compared with a threshold at to determine the onset of irradiation by the X-ray source which will appear as a rapid change in the signal level. The threshold conditions are varied to follow changes in ambient conditions and particularly temperature changes to allow for increase of dark current with a rise in temperature. This permits the threshold at which the CCD is triggered to begin image acquisition to be set at a relatively low level whilst minimising the risk of false triggering.