Abstract: A laser Doppler velocimeter uses self-mixing amplification of backreflections from scatterers below the surface of a flow. A time domain signal is divided into segments that are roughly equal to a transit time of particles through a focus of a laser beam. The segments are connected to a frequency domain through the use of an FFT algorithm to produce frequency domain data segments. Signal-to-noise ratio is enhanced through signal processing techniques using the segments to produce a final enhanced signal spectrum.

Abstract: A laser Doppler velocimeter uses self-mixing amplification of backreflections from scatterers below the surface of a flow. A time domain signal is divided into segments that are roughly equal to a transit time of particles through a focus of a laser beam. The segments are connected to a frequency domain through the use of an FFT algorithm to produce frequency domain data segments. Signal-to-noise ratio is enhanced through signal processing techniques using the segments to produce a final enhanced signal spectrum.

Abstract: A laser Doppler velocimeter is formed using a fiber laser as the lasing medium. Within the velocimeter, all optical signals, transmitted and received, are conveyed by optical fibers. An amplifier amplifies a source laser, which is then transmitted to one or more transceivers. The one or more transceivers, each projecting along a different axis, and each with a single optical fiber input/output interface act as both the transmission device to focus the radiation at a target region, and as the receiving system for collecting reflected radiation. The transceivers each include an amplifier to further amplify the radiation received from the laser source. The one or more transceivers transmit radiation simultaneously to the target region, and may be located remotely from the laser source. The portion of the reflected radiation collected by the receiving system is analyzed to determine the Doppler shift caused by targets at the focal point of the one or more transceivers.

Abstract: A system and method for measuring wind velocities are provided. A laser wind velocimeter with a radiation source includes a fiber laser. All optical signals, transmitted and received, are conveyed by optical fibers. An amplifier amplifies a source laser, which is then transmitted to one or more transceivers. The one or more transceivers, each projecting along a different axis, and each with a single optical fiber input/output interface act as both the transmission device to focus the radiation at a target region, and as the receiving system for collecting reflected radiation. The one or more transceivers transmit radiation to the target region. A portion of the reflected radiation collected by the receiving system is analyzed to determine the Doppler shift, which can me used to measure wind velocity.

Abstract: A method and apparatus for carrying out a seismic exploration. A seismic event is applied to the earth's surface, particles at the earth's surface move in response to the event and the response to the event is detected using an interferometer. The earth's surface and the interferometer move with respect to each other. The detectors of the interferometer may be arranged in an array. The detected response may be analyze.

Abstract: Systems and methods for laser based measurement of air parameters are disclosed. An example system includes a source of radiation, an amplification system with one or more power amplification stages, a transceiver, and an optical mixer. The source produces a plurality of beams, and the amplification system is configured to amplify the beams. The transceiver is configured to transmit the modulated beam to, and receive a scattered beam from a target region. The optical mixer is configured to determine a difference between the scattered beam and a reference beam, which is used to determine a Doppler shift therefrom. In certain embodiments, the amplification system includes a fiber preamplifier and one or more fiber power amplifiers stages.

Abstract: A motion rate sensor for detecting the rate of movement of an article, comprising: a housing relative to which, in use, the article moves, a detection unit disposed within the housing, the detection unit including a conversion device adapted for generating detector signals caused by the motion of the article, and processing circuitry adapted for receiving said detector signals and outputting motion signals indicative of the rate of movement of the article. In embodiments, the detector signals are caused by variations in optical or light energy, in magnetic fields or radiation intensity. The variations may be caused by variations on the surface in the article, for example a random or repetitive pattern. An apparatus and method for calibrating the sensor are also disclosed, as are a system and method for determining the speed of motion of an article using the sensor.

Abstract: A zeta potential measurement system comprising: a cell having a cell wall and bottom for holding suspended particles; an optical measurement probe having a probe tip comprising a transparent and conducting thin film coating which prevents ionic current from accumulating charge on the probe tip, and wherein the optical measurement probe is inserted through the cell wall such that the probe tip is in fluid communication with the sample; a counter electrode inserted through the cell wall opposite to the optical measurement probe; a laser source which is disposed so as to deliver light to the optical measurement probe via an optical directional coupler and optical waveguide; wherein the optical measurement probe focuses the light onto a front surface of the probe tip, such that the light reflected from the front surface of the optical measurement probe and light backscattered from particles in the sample are collected by the probe tip, and thereafter focused to a optical waveguide and delivered through the couple

Abstract: An optical anemometric probe includes a laser source emitting a linearly polarized primary light beam and an optical block having splitting means for separating the primary beam, an optical reference pathway, an optical emission pathway and an optical measurement pathway. The optical block includes optical means of rotation of the polarization arranged at the output of the laser source and before the splitting means. The optical emission pathway has an optical circulator, a first optical emission/reception head illuminating a first measurement zone, and a second optical emission/reception head illuminating a second measurement zone. The optical circulator has four ports, e.g., a first input port, a second and a third input/ouput port linked respectively to the first optical head and to the second optical head, and a fourth port linked to the optical measurement pathway.

Abstract: In a Doppler velocimeter, the incoming Doppler-shifted beams are heterodyned to reduce their frequencies into the bandwidth of a digital camera. This permits the digital camera to produce at every sampling interval a complete two-dimensional array of pixel values. This sequence of pixel value arrays provides a velocity image of the target.

Abstract: A Lidar measurement device for vehicular traffic surveillance and method for use of same are disclosed. In one embodiment, video circuitry acquires video of a field of view having a target therein. A steerable laser progressively transmits laser range-finding signals to the field of view in a horizontal and vertical step-wise manner and receives reflected laser range-finding signals from the target. A processing circuit portion determines target data of the target based upon range and time measurements associated with the reflected laser range-finding signals. The processing circuit then integrates the target data into the video such that the video may displayed with an image of the target and speed measurement associated therewith.

Abstract: Methods and systems for collecting high-density wind velocity data for the inflow area of a wind turbine are presented. Wind turbines are provided with one or more wind velocity sensors that provide a plurality of wind velocity measurements to the turbine from various ranges and locations across the inflow. Sensors are proximate to the wind turbine. Sensors mounted on the turbine's nacelle work collaboratively to provide the wind velocity measurements. Sensors mounted on the turbine's hub spin with the turbine blades. Spatial and temporal wind mapping provides improved fidelity of data to the wind turbine control system.

Abstract: The present invention relates to a system for determining distance between a first platform and a second platform. In one embodiment, the first platform includes a plurality of receivers which are positioned at different distances from the second platform. Each receiver receives a signal from the second platform. Each receiver includes multiple time slots for placing the received signal in a time slot that corresponds to an arrival interval of the received signal. The system also includes a processor for determining the distance between the first and second platforms based on examining the arrival interval of the received signal in each of the receivers.

Abstract: Method of measuring the velocity of an aircraft at a given instant, by laser Doppler anemometry, by performing the steps of acquiring a backscattered signal on at least three oriented line-of-sight axes, and calculating the spectrum of the backscattered signal on each of the line-of-sight axes. Further, acquiring an additional backscattered signal on at least one additional line-of-sight axis (X4) not coincident with one of the three first line-of-sight axes (X1, X2, X3), and calculating the spectrum of the backscattered signal on the additional line-of-sight axis (X4). Several candidate velocity vectors ({right arrow over (V)}c) and of the projections of the candidate vectors on at least one line-of-sight axis (X1, X2, X3, X4) are calculated. The consistency of the candidate vectors ({right arrow over (V)}c) is calculated as a function of their projections and as a function of each spectrum of the corresponding backscattered signal on the respective calculation axis (X1, X2, X3, X4).

Abstract: A colored noise reduction method for an optical remote airflow measurement apparatus, which emits laser light into the atmosphere as a transmission signal and measures a wind speed of an airflow in a remote region on the basis of a Doppler shift amount of a frequency between the transmission signal and a reception signal, includes: considering a signal strength of scattered light to be substantially non-existent in a remotest region and beyond; calculating a noise distribution by performing processing to average the signal strength in respective Doppler frequency components divided at intervals of a certain frequency in the remotest measurement region and beyond, and performing subtraction processing in each of the Doppler frequency components on all signal strength distributions of the measurement region, which are obtained by dividing the noise distribution at intervals of a certain distance.

Abstract: An accelerometer instrument is provided for measuring acceleration. The instrument includes a laser, a Mach-Zender interferometer (MZI), a mechanical spring, a detector, a camera, and an analyzer. The laser emits a coherent light beam of photons. The MZI includes first and second beam-splitters along with first and second mirrors. The first mirror has an established mass m and connects to the spring for vibrating substantially perpendicular to its reflection plane. The mechanical spring has an established spring constant k. The MZI has an established weak measurement Nw based on a known offset ? for the beam-splitters. The detector detects the beam beyond the second beam-splitter. The camera provides a pointer measurement shift ?q of the photons. The camera is disposed after the detector. The analyzer determines the acceleration ? based on a = ( k mN w ) ? ? ? ? q .

Abstract: A flow meter for use in dialysis is described, that uses a thermal wave to generate a signal in the fluid for which the flow rate is to be measured. The phase angle of the thermal wave signal changes when traversing downstream. The phase difference between the signals received downstream, compared with a reference excitation source signal is measured, and used to determine the flow rate of the fluid.

Abstract: Disclosed are personal electronic devices (PEDs) having a sensory enhancement (SE) system for monitoring environmental conditions and detecting environmental events, for example but not limited to, changes in acoustic, thermal, optical, electromagnetic, chemical, dynamic, wireless, atmospheric, or biometric conditions. The detection of such events can be used to invoke a notification, an alert, a corrective action, or some other action, depending upon the implementation to the PED user or another party.

Abstract: A physical quantity sensor includes a semiconductor laser for irradiating an object with a laser beam, and a laser driver for operating the semiconductor laser in such a way that a first oscillation period for which the oscillation wavelength increases and/or a second oscillation period for which the oscillation wavelength decreases is repetitively present. The sensor further includes a photodiode and a current-voltage conversion amplifying unit both for detecting an MHP containing an interference waveform formed by the self-coupling effect between the laser beam and the returning light beam from the object, a MHP extracting unit for measuring the period of the interference waveform contained in the output signal from the current-voltage conversion amplifying unit each time the interference waveform is inputted, and a computing unit for computing the displacement and/or the speed of the object from the measured individual period MHP extracting unit.

Abstract: Obtaining global tropospheric vertical wind profiles by directly detecting atmospheric winds using space borne, airborne and/or ground station platforms is accomplished by a DASH interferometer in the back-end of a Doppler wind LIDAR. In the front-end of the Doppler wind LIDAR, a laser illuminates an atmosphere and a telescope collects backscattered laser light return signals from the laser illuminated atmosphere. The DASH interferometer processes return signals from the atmosphere, forming an interferogram and determines from the interferogram a Doppler shift of the return signals, which is equivalent to determining the line of sight wind speed of the Doppler wind LIDAR observation, by measuring the frequency shift caused by winds.

Abstract: The invention relates to a method for measuring a relative velocity between an object surface (O) and a sensor (1) having at least one light-sensitive element (2) according to the spatial frequency filtering method, wherein the light-sensitive element (2) is read out at time intervals, and wherein the spatial frequency filter is designed as at least one masking grating having a variable grating constant. The method according to the invention is characterized in that the relative velocity is firstly measured with a first grating constant k1 having a large period length and/or over a short observation time period t1 (rough measurement) and then the measurement of the relative velocity is repeated for an exact determination using a second grating constant k2 having a small period length and/or over a long observation time period t2 (fine measurement). The invention further relates to a sensor for velocity measurement.

Abstract: Embodiments of the present invention are low cost, robust, broadband, optimum, high precision methods and apparatus of processing pulsed, transient, non-cooperative, non-reproducible, complex, or simultaneous signals based on correlation measurements utilizing optical RF signal train generators. An embodiment of the inventive apparatus comprises: (a) a signal receiving apparatus which receives one or more signals, and outputs the signals; (b) a replica generation apparatus, which comprises one or more RF signal train generators, accepts signals from the receiving apparatus as inputs, and outputs trains of replica pairs, where relative separations between two members in the replica pairs are same or different; and (c) an integration apparatus which performs Doppler, self, or mutual (cross) correlation operations on the replica pairs at RF or optical level.

Abstract: A laser Doppler velocimeter uses self-mixing amplification of backreflections from scatterers below the surface of a flow. A time domain signal is divided into segments that are roughly equal to a transit time of particles through a focus of a laser beam. The segments are connected to a frequency domain through the use of an FFT algorithm to produce frequency domain data segments. Signal-to-noise ratio is enhanced through signal processing techniques using the segments to produce a final enhanced signal spectrum.

Abstract: Methods and systems for using laser Doppler velocimeters to determine and use wind velocities at the locations of impending and occurring events such as sports events are presented. Laser Doppler velocimeters are used to determine wind velocities where an event is occurring or an impending event is about to occur. The determined wind velocities are used to generate and display a representation of the impending or occurring event that accounts for the effect of the determined wind velocities on the impending or occurring event.

Abstract: The present invention concerns a single-particle LIDAR anemometry method and system comprising the continuous emission of one or more light beams through a gas containing particles, said beam being focused onto a measurement volume, a step of detecting a signal backscattered by particles passing through said volume, the method being characterized in that it comprises at least the following phases: determining in a time period ?t the frequency of each of the pulses included in the backscattered signal; distinguishing pulses based on duration and/or intensity and/or frequency-modulation criteria; and estimating the displacement velocity of said beam relative to the gas from several of the frequencies determined over the time period ?t excluding those corresponding to the pulses distinguished during the preceding step A notable application of the invention is for the measurement of the airspeed of an aircraft.

Abstract: A method for use in controlling a system includes tracking three-dimensional movements of a hand-held controller for the system, mapping the tracked three-dimensional movements of the handheld controller onto a two-dimensional image plane of a screen of a display for the system, and displaying one or more images on the two-dimensional image plane of the screen based on the mapping of the tracked three-dimensional movements of the handheld controller. Some embodiments may include one or more sensors configured to track three-dimensional movements of a hand-held controller for the system, and a processor configured to perform the above mentioned steps.

Abstract: A scanning-type distance measuring apparatus includes: an optical system 9 having a first deflecting member 9a that deflects measurement light output from a light transmitting unit 3 toward a space to be measured via an optical window, a light receiving lens 9c that condenses reflection light from an object R to be measured existing in the space to be measured, and a second deflecting member 9b that deflects the reflection light passed through the light receiving lens toward a light receiving unit 5 disposed to oppose the light transmitting unit 3; a scanning mechanism 4 that rotates the optical system 9 about a predetermined axis P; and an optical member 90 that outputs the measurement light deflected by the first deflecting member 9a from an incident light path Lc of the reflection light to the second deflecting member 9b.

Abstract: An optical method and apparatus are described for the measurement of properties of a travel vehicle or a travel surface upon which the travel vehicle travels, which includes providing an incident light from a light source to the travel surface, collecting light reflected from the travel surface, determining a surface induced Doppler shift from the incident and collected light and determining at least one of a motion property of the travel vehicle and a surface property of the travel surface based on the determined surface induced Doppler shift.

Abstract: A system for computation of wind velocity including a laser adapted to transmit a beam to a target, a collecting lens for receiving a beam returning from the target, and receiver optics comprising a multi-element detector array at a focal plane of the collecting lens, wherein for each element of the multi-element detector array there is a specific optical path in the atmosphere leading from the laser to the target and back from the target to the element; and processor apparatus operative to measure signal fluctuations of an element of the multi-element detector array, and compute therefrom crosswind velocity of wind in the atmosphere, wherein said processor apparatus is operative to calculate turbulence strength changes and wind profiles.

Abstract: A Doppler velocimeter apparatus that may have a coherent light source for generating a beam of coherent light. A modulating subsystem may receive and modulate at least a first portion of the beam of coherent light to form a first beam portion, the first beam portion forming a frequency offset and being a modulated, coherent optical signal. An optical element may receive the first beam portion and direct the first beam portion at a subject, the first beam portion being reflected from the subject to form a reflected beam that has a frequency that is modified in relation to the motion of the subject. A processing subsystem may receive a second portion of the beam of coherent light, and also the reflected beam, and uses the second beam portion and the reflected beam to determine a Doppler shift of the reflected beam.

Abstract: A method of an apparatus for measuring or determining the movement characteristics of an object uses the detection of changes in beams. A set of beams F1-B1, F2-B2, F3-B3 is disposed in the movement path of the object; at relative angles to each other; and at acute angles to the intended direction of the object. The number of changes in the beams or durations between changes in the beams are recorded. The relative times, durations or differences in relative times, at which different beams of the set are changed are measured. The resulting measurements are associated with the relevant movement characteristics of the object.

Abstract: A device comprises: an emitting element for emitting a laser beam, referred to as an emitted beam; a focusing element for focusing the emitted beam at a predetermined focal distance (D); a receiving element for receiving the emitted beam after being reflected by a particle in the air (18), referred to as a reflected beam; a transmitting element for transmitting the signal of interference occurring between the emitted beam and the reflected beam to a signal processor in order to deduce the speed of the particle therefrom. The emitting element includes a laser diode and the receiving element is combined with the laser diode by self-mixing. The focal distance is between 5 cm and 2 m.

Abstract: In one embodiment, a three dimensional imaging system includes a portable housing configured to be carried by a user, microelectrical mechanical system (MEMS) projector supported by the housing sensor supported by the housing and configured to detect signals emitted by the MEMS projector, a memory including program instructions for generating an encoded signal with the MEMS projector, emitting the encoded signal, detecting the emitted signal after the emitted signal is reflected by a body, associating the detected signal with the emitted signal, comparing the detected signal with the associated emitted signal, determining an x-axis dimension, a y-axis dimension, and a z-axis dimension of the body based upon the comparison, and storing the determined x-axis dimension, y-axis dimension, and z-axis dimension of the body, and a processor operably connected to the memory, to the sensor, and to the MEMS projector for executing the program instructions.

Abstract: Systems, devices and methods of producing an image are provided. A electro-magnetic radiation source provides electro-magnetic radiation to a sample and a reference. A detector/interferogram unit produces at least one interferogram that is supplied to a signal processing unit. The signal processing unit extracts phase, magnitude, and/or polarization data from the supplied signals, and produces an image based on at least the extracted data.

Abstract: The present invention refers to a method of operating a self-mixing interference sensor and a corresponding self-mixing interference sensor device. In the method the laser (1) of the device is controlled to periodically emit a laser pulse followed by an emission period of laser radiation having a lower amplitude. The pulse width of the laser pulse is selected such that the pulse after reflection at the object (3) re-enters the laser (1) during the emission period of laser radiation with lower amplitude. The corresponding SMI signal has an increased signal to noise ratio.

Abstract: A magnitude and direction, or a measure responsive thereto, of a velocity (V) of a first portion (17) of an atmosphere (20) are determined from at least first and second portions of scattered light (30) generated along a common beam of light (28) within the first portion (17) of the atmosphere (20) and received along linearly independent directions at locations that are relatively remote with respect to one another, at least one of which is relatively remote from a source (11) of the beam of light (28).

Abstract: A liquid droplet measurement apparatus has: a first laser light source emitting a laser light; a first optical device which makes, in terms of a beam cross-section of the laser light, a beam width in a direction perpendicular to a direction of ejection of a liquid droplet, greater than a beam width in the direction of ejection of the liquid droplet, and makes light intensity of the laser light fall within a prescribed range within a range where variation in a position of the liquid droplet occurs in the direction perpendicular to the direction of ejection of the liquid droplet, at a position where the laser light from the first laser light source is irradiated onto the liquid droplet ejected; a first light receiving device which receives the laser light that has been irradiated onto the liquid droplet by the first optical device and generates a determination signal; and a first liquid droplet characteristics calculation device which calculates at least one of a volume of the liquid droplet and a velocity of t

Abstract: A sensor for sensing speeds, at least including a sensor unit, which has a radiation emitter element, a sensor element, a preliminary optical element and an evaluation circuit, a sensor housing, which has a leadframe, and a dirt guard unit, which includes a lens, wherein the sensor unit is in electrical contact with the leadframe of the sensor housing, and the lens of the dirt guard unit caps off the sensor housing as a cover.

Abstract: A method of detecting the velocity of a moving object comprising the steps of: passing a beam of coherent light through an optical mask having a pattern of alternating opaque and non-opaque regions formed thereon, whereby an image of alternating light and dark fringes is projected along the length of the light beam; causing the moving object to pass through the projected image such that a portion of the light beam is reflected from the moving object as a series of pulses; detecting the reflected light pulses and the frequency of the pulses; and calculating the velocity of the object as a function of the pulse frequency and the known separation of the fringes of the image.

Abstract: A method for transitioning a target from a missile warning system to a fine tracking system in a directional countermeasures system includes capturing at least one image within a field of view of the missile warning system. The method further includes identifying a threat from the captured image or images and identifying features surrounding the threat. These features are registered with the threat and image within a field of view of the fine tracking system is captured. The registered features are used to identify a location of a threat within this captured image.

Abstract: A method of analyzing pulses from a flow cytometer in which particles in a fluid pass through an excitation volume of an electromagnetic radiation and interact with the electromagnetic radiation to generate signals in the form of pulses includes generating a time-dependent pulse indicative of the characteristics of one or more particles passing through the excitation volume of the electromagnetic radiation, determining a measurement window by selecting a portion of the pulse with a starting point and an ending point above a predetermined value, and calculating a first derivative of the pulse with respect to time over the measurement window.

Abstract: A device and method for measuring moving material includes a processor and operating software associated therewith; a light source for emitting at least two polarized light beams in a manner wherein the beams cross thereby creating an interference region and generate a set of fringes; a sensor aligned relative to the interference region wherein the fringes have a predetermined orientation to the directional movement of the material and wherein the sensor is operably equipped to receive scattered light emanating from the interference region and provide a time varying signal to the processor such that the processor can manipulate and convert the signal to speed and distance and a polarizing filter operably associating a polarizing filter with one of the sensor and the emitting means in a manner to substantially preclude reflected polarized light from the interference region back to one of the sensor and the emitting source.

Abstract: An object of the present invention is to provide a method enabling measurement in a wider range than a conventional LIDAR system and capable of measuring airflow information, which is used to reduce shaking of an airframe when an aircraft collides with turbulence, in a shorter period, and a device having corresponding functions. A multi-LIDAR system according to the present invention includes at least two optical remote airflow measurement devices of a Doppler LIDAR system employing laser light that are provided in a fixed relative position relationship, has functions for emitting lasers of identical wavelengths from the respective devices and receiving scattered light by the respective devices, thereby improving redundancy with respect to defects, and improves a detectability by increasing an integration amount of respective measurement signals.

Abstract: A demodulating system (100) for demodulating a phase-modulated input signal (Si) comprises: a complex demodulator (110), having a first input (111) for receiving the phase-modulated input signal (Si) and being designed to perform complex multiplication of this signal with an approximation of the inverse of the phase modulation; a spectrum analyzing device (130) receiving the demodulated product signal produced by the complex demodulator (110) and capable of analyzing the frequency spectrum of the demodulated product signal.

Abstract: A method and an arrangement are provided to determine the speed of the wind, which acts on a wind-blade of a wind-turbine. An optical-signal with a known frequency is sent from an optical-transmit-unit to a joint measurement volume. The optical-signal is scattered and reflected by atmospheric particles of the joint measurement volume. The optical signal is shifted in its frequency due to the Doppler-principle, too. The frequency-shifted optical signal is received by a receive-unit. The frequency-shifted optical signal is compared with the sent optical-signal to determine the wind-speed based on the shifted frequency, which is caused by the atmospheric particles.

Abstract: A traffic violation or event detection, recording and processing system and method is disclosed which includes at least one camera (20 and 30) for monitoring a region under surveillance (31 and 33); means for supplying independently sourced and verifiable time, date and location of a violation; a storing means (54) for storing continuous images taken by the camera; a non-intrusive violation detection means for detecting vehicle presence and movement and for providing an indication of a violation; and processing means for identifying images stored in the storage means and which relate to a violation detected by the violation detection means so that images associated with a violation are identifiable and can be processed to provide evidence of the violation and also identify the vehicle associated with the violation.

Abstract: Disclosed is a laser doppler velocity system that can easily change a focal length of laser beam, in order to measure the velocity of fluid. As the fluid lens is used in order to focus the laser beam, the lens aperture is rapidly and accurately changed at a low power to easily measure the flow-velocity and shear stress of the boundary layer of the structure within the flow field. As the optical array including the fluid lens is integrated using a diode laser as a laser light source, the laser doppler velocity system can be made in small-size. Also, as the laser doppler velocity system is inserted into the surface of the structure, it can be used as a surface flow field measurement sensor.

Abstract: The invention relates to an apparatus (1) for determining a flow property of a fluid (2). The apparatus comprises a distance and velocity determination unit (3) for determining distances of elements of the fluid to the distance and velocity determination unit (3) and for determining velocities of the elements at the same time based on a self-mixing interference signal. The apparatus (1) comprises further a flow determination unit (4) for determining the flow property of the fluid (2) based on at least one of the determined distances and velocities. This allows determining the flow property, even if the fluid (2) is optically thick.

Abstract: A method for measuring the mean velocity (VH) of an extracorporeal blood fluid or infusion fluid, by means of retroinjection interferometry, comprises the step of emitting a first laser light beam (41), from the laser cavity (40) of a semiconductor laser source (60), reflection of a second laser beam (45) by the fluid (50) and consequent generation of interference with the first laser beam (41) inside the laser cavity (40), detection of the interference signal by a monitoring photodiode (46), and processing, by means of an electronic processing and control circuit (100), of the interference signal detected. The invention also comprises an apparatus (62) for implementing the method described and an extracorporeal circuit (58) comprising said apparatus. The invention also comprises a method for replacing a laser source in said apparatus.

Abstract: The invention relates to a device for detecting and measuring wind at the front of an aircraft, said device comprising a lidar for the cyclic measurement of wind speeds at least a couple of measuring points located at the same distance, so-called measuring distance, from the nose of the aircraft. The invention is characterised in that it is suitable for measuring wind speeds, at each cycle, by means of the lidar, at a plurality of couples of measuring points (1-12) located at different measuring distances (xp-2, xp-1, xp), the difference between the largest measuring distance and the smallest measuring distance being more than 100 metres. The invention also relates to a method for detecting and measuring wind, which can be implemented by the device according to the invention.