Abstract: A measurement instrument is disclosed. The measurement instrument comprises a front lens assembly, a distance measurement module and a deflection module. The front lens assembly comprises an optical path along an instrument optical axis and the distance measurement module is configured to transmit and receive optical radiation along a measurement path. The deflection module is arranged between the distance measurement module and the front lens assembly to deflect the measurement path across the instrument optical axis.

Abstract: Methods and devices for detecting movement of an object includes: receiving a plurality of output signal values from a sound wave receiver, each of the plurality of output signal values being representative of a distance between the object and the sound wave receiver; determining, based on the received plurality of output signal values, a difference value representative of a difference between a first output signal value and a second output signal value among the plurality of output signal values; determining whether the difference value is representative of motion of the object based on whether the difference value has a magnitude between a predetermined minimum threshold and a predetermined maximum threshold; and outputting a motion detection signal if the difference value is determined to have a magnitude between the predetermined minimum threshold and the predetermined maximum threshold.

Abstract: A travel assist apparatus includes a calculator that calculates rear lane shape information in a section from a current position of the own vehicle to a rear position, on the basis of a lane information group and a traveling trajectory of the own vehicle. The lane information group includes pieces of lane information detected on the basis of images captured by an imaging unit successively during a data acquisition period. The pieces of lane information each includes information regarding relative positions of lanes with respect to an own vehicle. The data acquisition period is a predetermined period from a current time to a certain time in past. The traveling trajectory of the own vehicle is that during the data acquisition period and is calculated on the basis of a result of detection of both a vehicle speed and a yaw rate of the own vehicle during the data acquisition period.

Abstract: An electro-optical device includes a laser, which is configured to emit toward a scene pulses of optical radiation. An array of detectors are configured to receive the optical radiation that is reflected from points in the scene and to output signals indicative of respective times of arrival of the received radiation. A controller is coupled to drive the laser to emit a sequence of pulses of the optical radiation toward each of a plurality of points in the scene and to find respective times of flight for the points responsively to the output signals, while controlling a power of the pulses emitted by the laser by counting a number of the detectors outputting the signals in response to each pulse, and reducing the power of a subsequent pulse in the sequence when the number is greater than a predefined threshold.

Abstract: A laser distance measuring device for determining a distance to a target, in particular for a weapon system, comprises a first laser light source that is designed to emit laser pulses with a first pulse power, a second laser light source that is designed to emit laser pulses with a second pulse power, wherein the second pulse power of the second laser light source is higher than the first pulse power of the first laser light source (TX1), a receiver that is designed for receiving laser pulse radiation (RP) reflected by the target, an electronic controller for actuating the first laser light source, the second laser light source and the receiver. The electronic controller is designed to emit a first laser pulse by means of the first laser light source, after which, if a distance to the target cannot be determined with the first laser pulse by means of the receiver, a second laser pulse is emitted by means of the second laser light source.

Abstract: A distance measuring device according to an embodiment includes a weight value generator, a cumulative signal generator, and a distance measurer. The weight value generator generates, on the basis of similarity between a first digital signal obtained by digitizing reflected light of laser light irradiated in a first irradiation direction and a second digital signal obtained by digitizing reflected light of laser light irradiated in a second irradiation direction different from the first irradiation direction, a weight value of the second digital signal. The cumulative signal generator accumulates, on the first digital signal, a signal obtained by weighting the second digital signal with the weight value and generates a third digital signal. The distance measurer measures a distance to a target object on the basis of a time difference between irradiation timing of the laser light and timing of a peak position in the third digital signal.

Abstract: Methods and systems for performing three dimensional LIDAR measurements with an integrated LIDAR measurement device are described herein. In one aspect, a Gallium Nitride (GaN) based illumination driver integrated circuit (IC), an illumination source, and a return signal receiver IC are mounted to a common substrate. The illumination driver IC provides a pulse of electrical power to the illumination source in response to a pulse trigger signal received from the return signal receiver IC. In another aspect, the GaN based illumination driver IC controls the amplitude, ramp rate, and duration of the pulse of electrical power based on command signals communicated from the return signal receiver IC to the illumination driver IC. In a further aspect, illumination driver IC reduces the amount of electrical power consumed by the illumination driver IC during periods of time when the illumination driver IC is not providing electrical power to the illumination source.

Abstract: Pulsed light illuminator for generating at least one light pulse having a predefined rise time and fall time, including a semiconductor light source, an electronic driver coupled with the light source and a synchronization controller coupled with the electronic driver, the electronic driver including an active switch coupled with the light source, a switch driver coupled with the active switch and the controller, a high voltage power supply, a fast voltage provider, a low voltage power supply, a first switch coupled with the low voltage power supply and the light source, a second switch coupled with the high voltage power supply and the light source and an energy discharger coupled with the light source, the light source for generating and emitting the light pulse, the electronic driver for providing a drive current to the light source and the controller for synchronizing a timing of the active switch via a synchronization signal.

Abstract: The present invention relates to an apparatus for damping arid monitoring emissions from a light emitting device, particularly a vertical cavity surface emitting laser (VCSEL), comprising: a semi transparent substrate, preferably glass; a light emitting device for generating light emission; a damping layer deposited on a surface of the substrate; and a pair of electrodes, each of which being in direct contact with the damping layer. The damping layer is adapted to decrease the power level of the light emission of the light emitting device by absorption, to a desired level, for instance, to a level that meets eye safety limits. In addition, the damping layer is photosensitive to the light emission of the light emitting device, thereby allowing the pair of electrodes to output an electric signal corresponding to the power level of the light emission of the light emitting device.

Abstract: An example laser system includes a laser source to transmit a source light generated based on optical feedback provided by a laser cavity. The laser system further includes a beam-splitter to split the source light into a reference light and a split source light. The laser system further includes a modulator to modulate the split source light's frequency. The modulated light may be transmitted towards and reflected from a target. The modulator and beam-splitter may receive, frequency-modulate, and pass the reflected light to the laser cavity. The laser cavity amplifies the reflected light and transmits the amplified light toward the beam-splitter, such that the amplified light follows a same path as the reference light. The laser system further includes a detector to receive the reference light and amplified light, and detect a beating frequency as an indication of presence of the reflected light. Related methods and devices are also disclosed.

Abstract: An optoacoustic imaging system includes an ultrasound transducer array, first and second light sources and a switching power supply that generates power for the light sources. The switching power supply includes an input for impeding its switching operation. A data acquisition unit samples the ultrasound transducer array for a first predetermined period of time after a pulse of light from the first light source and for a second predetermined period of time after a pulse of light from the second light source and stores the sampled data. A master processor utilizes the input to impede operation of the switching operation of the switching power supply during the first predetermined period of time after a pulse of light from the first light source, and during the second predetermined period of time after a pulse of light from the second light source.

Abstract: A conveyor mechanism conveys a powder along a path. A first camera device arranged above the conveyor mechanism detects movement of a recognizable feature on an upper surface of the powder over a period of time. A velocity of the powder can be determined based on the movement of the recognizable feature over the period of time. A device can be used to generate the recognizable feature. A first light-emitting device can illuminate the upper surface to aid detection of the recognizable feature. A second light-emitting device can project a contour line on the upper surface, and a second camera device can be used to detect a position of the contour line. A cross sectional area of the powder can be correlated based on the position of the contour line.

Abstract: A proximity sensor and proximity sensing method using a change in light quantity of a reflected light are disclosed. The proximity sensor may include a quantity change detection unit which detects a change in a quantity of reflected light which is output light which has been reflected by an object, where an intensity of the output light changes, and a proximity determination unit which determines a proximity of the object to the quantity change detection unit based on a change in the intensity of the output light and the detected change in the quantity of the reflected light.

Abstract: A three dimensional scanning beam system (100) and method (500) enable economical and efficient three dimensional scans of an environment. The system (100) includes a ranging apparatus (105), and a reactive linkage mechanism (110) having a first end (115) and a second end (120). The first end (115) is connected to the ranging apparatus (105) and the second end (120) is connected to an object (125) that moves the system (100) through an environment. In use acceleration of the object (125) with respect to the environment is converted by the reactive linkage mechanism (110) to motion of the ranging apparatus (105) with respect to the object (125), which increases the field of view of the ranging apparatus (105) with respect to the environment.

Abstract: Samples of a light radar (“LIDAR”) return signal are stored in an analog circular buffer following the transmission of a LIDAR pulse. Sampling continues for a fixed period of time or number of samples during a post-trigger sampling period after the occurrence of a trigger signal from a trigger circuit. The trigger circuit indicates the receipt of a return pulse associated with a target object based upon one or more return signal characteristics. Following the post-trigger sampling period, the stored analog samples are sequentially read out and converted to digital sample values. The digital sample values may be analyzed in a digital processor to further confirm the validity of the returned LIDAR pulse, to determine a time of arrival of the LIDAR pulse, and to calculate a distance to the target object. Some versions include multiple circular buffers and capture clocks, enabling the capture of samples from multiple return pulses.

Abstract: In a distance measurement device of an embodiment, a light source emits modulation light in a first charge transfer cycle, and emission of the modulation light of the light source is stopped in a second charge transfer cycle. In each of the first and second charge transfer cycles, the charges generated in a photosensitive region are distributed to a first accumulation region and a second accumulation region. A first value is obtained based on readout values corresponding to amounts of accumulated charges of the first accumulation region. A second value is obtained based on readout values corresponding to amounts of accumulated charges of the second accumulation region. A distance is calculated based on the first value and the second value.

Abstract: An in-line laser beam waist analyzer system includes an optical prism that picks off a portion of a second surface reflection from either a laser processing focus lens or a protective debris shield for the processing lens and directs that focused light to a pixelated detector. This provides real time monitoring of the focused laser beam while it is processing material by welding, cutting, drilling, scribing or marking, without disrupting the process.

Abstract: An in-line laser beam waist analyzer system includes an optical prism that picks off a portion of a second surface reflection from either a laser processing focus lens or a protective debris shield for the processing lens and directs that focused light to a pixelated detector. This provides real time monitoring of the focused laser beam while it is processing material by welding, cutting, drilling, scribing or marking, without disrupting the process.

Abstract: An in-line laser beam waist analyzer system includes an optical prism that picks off a portion of a second surface reflection from either a laser processing focus lens or a protective debris shield for the processing lens and directs that focused light to a pixelated detector. This provides real time monitoring of the focused laser beam while it is processing material by welding, cutting, drilling, scribing or marking, without disrupting the process.

Abstract: An image-based sensor system for a mobile unit makes use of light emitters and imagers to acquire illumination patterns of emitted light impinging on the floor and/or walls surrounding the unit. The illumination pattern is used to estimate location and/or orientation of the unit. These estimates are used for one or more functions of stabilization, calibration, localization, and mapping of or with respect to the unit.

Abstract: An in-line laser beam waist analyzer system includes an optical prism that picks off a portion of a second surface reflection from either a laser processing focus lens or a protective debris shield for the processing lens and directs that focused light to a pixelated detector. This provides real time monitoring of the focused laser beam while it is processing material by welding, cutting, drilling, scribing or marking, without disrupting the process.

Abstract: A system for three-dimensional hyperspectral imaging includes an illumination source configured to illuminate a target object; a dispersive element configured to spectrally separate light received from the target object into different colors; and a light detection and ranging focal plane array (FPA) configured to receive the light from the dispersive element, configured to acquire spatial information regarding the target object in one dimension in the plane of the FPA, configured to acquire spectral information in a second dimension in the plane of the FPA, wherein the second dimension is perpendicular to the first dimension, and configured to obtain information regarding the distance from the FPA to the target object by obtaining times of flight of at least two wavelengths, thereby imaging the target object in three dimensions and acquiring spectral information on at least one 3D point.

Abstract: An optical sensor system having a light source comprising a plurality of series connected light emitting diodes (LEDs). The series connected LEDs may be switched at a predetermined frequency.

Abstract: A device for optoelectronic distance measurement includes an emitter having a first end for emitting a measuring beam to an object to be measured and a second end, a receiver for receiving the measuring beam reflected or dispersed back from the object to be measured and for converting it to a measurement signal, a signal processing device for filtering the measurement signal and a reference signal, and a control and analysis device for analyzing the information of the measurement signal and the reference signal so as to determine the distance from the object to be measured. The second end of the emitter is used to emit a reference beam which is received by the receiver and converted to form the reference signal.

Abstract: An optoelectronic sensor (10) for the measurement of distances or distance changes in accordance with the light transit time principle is provided having a light transmitter (12) for the transmission of a light signal and having a light receiver (16) for the reception of the remitted or reflected light signal, wherein an evaluation unit (18) is provided which is made to trigger the transmission of a light signal at a transmission time in a respective measurement period (100) and to sample the received light signal as well as to accumulate a histogram (110) of such received light signals over a plurality of measurement periods (100) and to determine the reception time from the histogram (110) and the light transient time from this.

Abstract: The present invention determines the dimensions and volume of an object by using a novel 3-D camera that measures the distance to every reflective point in its field of view with a single pulse of light. The distance is computed by the time of flight of the pulse to each camera pixel. The accuracy of the measurement is augmented by capture of the laser pulse shape in each camera pixel. The camera can be used on an assembly line to develop quality control data for manufactured objects or on a moving or stationary system that weighs as well as dimensions the objects. The device can also ascertain the minimum size of a box required to enclose an object.

Abstract: An object is to enable a change in a frequency for which an electric signal based on an optical signal is measured by a spectrum analyzer. An optical measurement device includes a first photoconductive switch that receives predetermined pulse light from a first laser light source, and outputs terahertz light having the same repetition frequency as the repetition frequency of the predetermined pulse light. The optical measurement device also includes a second photoconductive switch that receives the terahertz light and a sampling light pulse, and outputs a signal corresponding to a power of the terahertz light at a time point when the sampling light pulse is received.

Abstract: A telescope with internal scanner utilizing either a single optical wedge scanner or a dual optical wedge scanner and a controller arranged to control a synchronous rotation of the first and/or second optical wedges, the wedges constructed and arranged to scan light redirected by topological surfaces and/or volumetric scatterers. The telescope with internal scanner further incorporates a first converging optical element that receives the redirected light and transmits the redirected light to the scanner, and a second converging optical element within the light path between the first optical element and the scanner arranged to reduce an area of impact on the scanner of the beam collected by the first optical element.

Abstract: A system and method is described for determining a distance to a desired target via correlating a pulse modulated signal with its corresponding reflected signal, while compensating for noise error in the reflected signal to allow for a more precise distance determination. The system and method determine a phase shift of an echoed signal in response to a transmitted signal incident onto an object to thereby determine a distance, wherein the system analyzes an overlap region between a second signal that is a reflection of a first signal incident on the object. The first signal is modulated by one or more pulses having a defined modulation frequency. Further details and features are described herein.

Abstract: According to the invention, a light signal is emitted to one or several targets in order to derive geodetic distance data therefrom. Apparatus components such as transmitters (1?) and receivers (4?) are modeled along with the targets (3a and 3b) as a linear, time-invariant system which is excited by means of a signal s(t) and the system response y(t) of which is recorded. Unlike in delay meters or phase meters, the distance data is derived from both the delay and the signal form of the system response.

Abstract: The invention relates to a method and an arrangement for performing triggering and for determining a triggering moment. In the solution, a unipolar electrical pulse of a detector (106, 118) is converted between the detector (106, 118) and a first amplifier (108, 120) succeeding the detector into at least one bipolar electrical oscillation. The bipolar electrical oscillation is amplified with at least one amplifier (108, 120) and triggering is performed at a zero level between the extreme values of the bipolar electrical oscillation. In addition, a triggering moment is determined, at which the amplified bipolar electrical oscillation crosses the zero level between its extreme values.

Abstract: A telescope with internal scanner utilizing either a single optical wedge scanner or a dual optical wedge scanner and a controller arranged to control a synchronous rotation of the first and/or second optical wedges, the wedges constructed and arranged to scan light redirected by topological surfaces and/or volumetric scatterers. The telescope with internal scanner further incorporates a first converging optical element that receives the redirected light and transmits the redirected light to the scanner, and a second converging optical element within the light path between the first optical element and the scanner arranged to reduce an area of impact on the scanner of the beam collected by the first optical element.

Abstract: An optical sensor system having a light source comprising a plurality of series connected light emitting diodes (LEDs). The series connected LEDs may be switched at a predetermined frequency.

Abstract: A first ranging apparatus includes a light emitter for emitting a modulated light which is intensity-modulated, a light detector for detecting a reflected light from an object that is irradiated with the modulated light, a distance calculator for calculating the distance up to the object based on the phase difference between the modulated light and the reflected light, and a gate controller. The gate controller outputs gate pulses to control a light emission controller to intermittently emit the modulated light to the object and also control an electrooptical shutter or an electronic shutter of an image capturing device to intermittently detect the reflected light from the object based on the intermittent emission of the modulated light.

Abstract: In an apparatus using an intensity-modulated light for detection of spatial information based upon light intensity of light reflected from a target space, a timing synchronization circuit is provided to synchronize a phase of the intensity-modulated light from a light-emitting element with a timing of operating a light-receiving element receiving the intensity-modulated light. The light-receiving element is caused to operate for enabling the detection of intensity of the received light for each of a plurality of phase regions within one cycle of the intensity-modulated light. The timing synchronization circuit functions to compare a cyclic variation determining the operation of the light-receiving element with a cyclic variation associated with an output from a light-emitting element driving circuit in order to keep a constant phase difference between these two cyclic variations.

Abstract: An air cargo power drive unit has a motor, at least one driver roller element coupled to said motor, a light source, a light detector, and a processor having memory associated therewith, said memory storing instructions. The device is configured to emit light from the light source, receive reflected light from the light detector when an air cargo is overhead, and convert the detected light into a time series of a digital samples representing a time-varying intensity of the received light. The processor then performs calculations on the digital samples to determine whether the unit load device is moving. This determination may be based, for instance, on spikes among the digital samples, and/or on first, second, or even higher-order, statistics of the detected samples.

Abstract: The invention is a process for identifying an unknown object. In detail, the process includes the steps of: 1) compiling data on selected features on a plurality of segments of a plurality of known objects; 2) illuminating the unknown object with a laser radar system; 3) dividing the unknown object into a plurality segments corresponding to each of the segments of the known objects; 4) sequentially measuring selected features of each of the plurality of segments of the unknown object; and 5) comparing the sequentially measuring selected features of each of the plurality of segments of the unknown object to the selected features on the plurality of segments of the plurality of known objects.

Abstract: A material measurement system (500) includes a THz generator including at least one laser source (111) for emitting optical pulses, the optical pulses coupled to a THz emitter (51) operable for emitting pulsed THz radiation at a sample location on material while being processed (14) by a manufacturing system. A receiver (52) is operable to receive the optical pulses and to detect reflected or transmitted THz radiation from the sample location (14) synchronously with the optical pulses and provide electrical detection signals. Synchronizing optics (112, 113, 114) is operable to receive the optical pulses from said laser and provide the optical pulses to both the receiver (52) and the THz emitter (51).

Abstract: A system for providing an objective visibility measurement to a flight crew preferably includes a LIDAR system (100), an evaluation unit (150), and a crew interface (200). In at least one embodiment, the system includes the capability of compensating for aircraft turns such that the absolute direction of the visibility reading remains constant through the maneuver. A method for providing an objective visibility reading to a flight crew preferably includes tacking a visibility reading (S820, S920); providing the visibility reading to the flight crew (S830, S930); and notifying the flight crew when the visibility has decreased to and/or less than a minimum visibility threshold (S840).

Abstract: A material measurement system (500) includes a THz generator including at least one laser source (111) for emitting optical pulses, the optical pulses coupled to a THz emitter (51) operable for emitting pulsed THz radiation at a sample location on material while being processed (14) by a manufacturing system. A receiver (52) is operable to receive the optical pulses and to detect reflected or transmitted THz radiation from the sample location (14) synchronously with the optical pulses and provide electrical detection signals. Synchronizing optics (112, 113, 114) is operable to receive the optical pulses from said laser and provide the optical pulses to both the receiver (52) and the THz emitter (51).

Abstract: A time difference measuring device can accurately measure a time difference between two pulse signals generated with a predetermined time difference by measuring the two pulse signals by one measurement. The time difference measuring device measures a time difference between a start signal (M1) and a stop signal (M2). The device has a reference signal generation unit (41) for generating two reference signals (S1, S2) having a ?/2 phase difference. According to corresponding amplitude values (A11, A12) and (A21, A22) of the reference signals (S1, S2) at each generation timing of the start signal (M1) and the stop signal (M2), a phase difference detection unit (42) calculates a phase difference ?? (=?stop??start) between the generation timings of the pulse signals (M1, M2). According to the detected phase difference ?? and the cycle (Ts) of the reference signals (S1; S2), a time difference calculation unit (44) calculates the generation time difference ?t between the pulse signals (m1, M2).

Abstract: Technology is disclosed for measuring distances. A measurement device emits a beam that reflects on the surface of an object. The measurement device determines the distance to the object, based on the time of flight of the beam from transmission to capture by the measurement device. The measurement device derives feedback reference pulses from pulses in the emitted beam and injects them into the device's receive path—creating a receive waveform that includes one or more feedback reference pulses and corresponding pulses in the return beam. The device uses the pulses in the waveform to measure time of flight. The measurement device can attenuate the feedback reference pulses to intensities similar or equal to the intensities of the return pulses. The measurement device can include a histogram processor that collects waveform samples at varying comparison thresholds.

Abstract: Apparatus for determining distance comprising a transmitting unit for emitting a light pulse, a receiver matrix having at least one photoelectric element and a control unit, wherein the receiver matrix has a first and a second integrator which are connected to the photoelectric element, which are activatable independently of each other and which are each adapted to integrate a measurement signal outputted by photoelectric element over a period of time predetermined by the control unit and thereby to form an integrator state and to output the integrator state as an output signal.

Abstract: The present invention comprises systems and methods for preventing collisions between aircraft and ground vehicles. In one embodiment, a system includes a proximity detection unit and a transducer proximate to a selected structural portion of an aircraft, the proximity detection unit being operable to emit ranging signals through the transducer and to receive reflected signals through the transducer to determine the position of an object within a ranging area adjacent to the structural portion. The system further includes an alarm device coupled to the proximity detection unit that is responsive to a signal generated by the proximity detection unit. In another embodiment, a method includes determining a distance between the ground service vehicle and a selected structural portion of the aircraft when the vehicle is positioned in a ranging area about the aircraft. The method further includes generating a proximity alarm based upon the distance.

Abstract: A LADAR apparatus and a method for use in receiving a LADAR signal are disclosed. The apparatus includes an optical pickup capable of picking up a plurality of optical signals; a timing synchronization reference; a time domain multiplexer capable of multiplexing the optical signals into a multiplexed optical signal relative to the timing synchronization reference; and an optical detector capable of detecting the multiplexed optical signal. The method include time domain multiplexing a plurality of LADAR signals into multiplexed LADAR signal; detecting the multiplexed LADAR signal; and demultiplexing the detected LADAR signal.

Abstract: The radar apparatus includes a transmit/receive section having a function of emitting a transmission wave, receiving the transmission wave reflected from a reflecting object, and outputting a reception signal having a signal level depending on the intensity of the received transmission wave, a control section controlling the transmit/receive section to transmit the transmission wave a predetermined number of times in the same direction, an integrating section successively integrating the reception signal successively outputted from the transmit/receive section to thereby successively form an integrated signal while the transmit/receive section repeatedly emits the transmission wave in the same direction, and a detector section judging whether or not the integrated signal enables detection of the reflecting object.

Abstract: A laser range finder, including a transmitter, a receiver, a timing-counting module, and a processor is provided. The transmitter transmits a laser signal toward a target, and a reflected signal is reflected from the target, whereby a real fly time is defined. The time-counting module generates a plurality of timing units to measures the real fly time to obtain a measured fly time. The processor generates a distance value based on the measured fly time.

Abstract: A ranging apparatus 1 comprises a laser light emitter 3 for emitting pulsed laser light, a reflected light receiver 4 for receiving reflected light, a distance computer 10 for finding the distance from the elapsed time until the reflected light is received, and a distance display 8 for displaying this distance. The distance computer 10 has a counter 11 for counting the frequency when the reflected light satisfies a specific condition, a table production component 12 for producing a frequency distribution table corresponding to distance by adding up the counts, a distance determiner 13 for determining as the distance to the object of measurement the point when the frequencies in the frequency distribution table exceed a threshold, and a distance selector 15 for selecting a specific distance when a plurality of distances are determined, and displaying this distance on the distance display 8.

Abstract: A method and system for performing swept-wavelength measurements within an optical system incorporating a reference resonator provides improved operation in resonator-enhanced optical measurement and data storage and retrieval systems. The system includes an illumination subsystem, an illumination coupler for producing a measurement beam and a reference beam from an output of the optical illumination source, a reference resonator for receiving the reference beam, a measurement resonator for receiving the measurement beam, at least two detectors, one optically coupled to the reference resonator and one optically coupled to the measurement resonator, and a time-domain measurement system coupled to the detectors for comparing detected optical signals received from the resonators. The detected signal from the reference resonator is used to compensate or detect variations in the wavelength of the illumination system, improving the resolution and accuracy of the measurement provided by the measurement resonator.

Abstract: The invention relates to a method of measuring the distance between a fixed point and an object, by the steps of: a) transmitting a light pulse (11) from the fixed point at a selected instant of transmission; b) periodically scanning of light intensity received at the fixed point and continuously storing, as a set of received scanned signal values, the scanned values at the scanning rate during a predetermined measuring time window (13) embracing the instant of reception of the light pulse reflected from the object; c) repeating steps a) and b) N number of times in order to obtain N number of sets of received signal values; d) summing the individual stored sets of received scanned signal values, set by set, to a summed scanned value set during a calculating window (14) following the N measuring time windows (13); e) repeating steps a) through d) in order to obtain a further summed scanning value set, whereby during or following step d) the further summed scanned value set is added, scanned value set by s