Abstract: A semiconductor laser source of a transmitter (102) in a range imaging apparatus (100) generates an optical pulse at repeated moments, and outputs spatially separate optical beams towards a target zone (114), such that the semiconductor laser source outputs each of the spatially separate of the optical beams at different moments from each other. A detector (105) of a receiver (104) comprises single-photon sub-detector units, at least two groups of the single-photon sub-detector units have separate field of views towards the target zone (114), and the at least two groups of sub-detector units are associated with different optical beams of the spatially separated optical beams on the basis of the separate field-of-views. A timing unit (106) determines a value corresponding to a time-of-flight of the optical pulse output at each of the repeated moments on the basis of a signal from a group of the sub-detector units associated with an optical beams output at said moment.

Abstract: Embodiments of the present disclosure provide a gimbal control method. The method includes receiving a first position and a second position wherein the first position and the second position are touched positions of an operation interface of a terminal; determining a rotation angle of the gimbal based on the first position, the second position, and an attitude of the gimbal at the first position; and controlling rotation of the gimbal based on the rotation angle.

Abstract: A rotation speed measurement method based on a femtosecond optical frequency comb is provided. In the method, a rotation axis of a rotating object to be measured and an optical path main axis are coplanar, and perpendicular to each other, and a first converging lens focuses an emitting beam obtained by expanding the laser on a surface of the rotating object. A repetition frequency and a carrier-envelope offset frequency of the femtosecond optical frequency comb are locked during the measurement. A repetition frequency difference is read from a frequency counter. A rotation speed of the rotating object is calculated as follows: M = c ? ? ? f r 4 ? ? ? f r ? sin ? ? ? R = ? ? ? ? f r R .

Abstract: Method and system for on-chip processing to obtain an EDOF image combines interferometry and imaging so the two operations do not interfere with one another but, rather, work together to create an in-focus, true color image of a three-dimensional object. This image has no significant artifacts and requires only limited processing. In addition, a coarse depth map is created in the process which may also be helpful in subsequent usage of the acquired image. A CMOS pixel-array sensor includes circuitry to implement processing at the pixel level.

Abstract: A laser radar device (1) includes: a light source array (10) for simultaneously emitting a plurality of laser light beams from a plurality of light emitting ends; an optical modulator (12) for modulating transmission light separated from the plurality of laser light beams to generate modulated transmission light; a transmission/reception optical system (14, 15) for receiving, as received light, the modulated transmission light reflected by a target, while scanning external space with the modulated transmission light; an optical combiner (16) for generating a plurality of interference light components by combining a plurality of local light components separated from the plurality of laser light beams and the received light; an optical receiver array (17) for generating a plurality of detection signals by detecting the plurality of interference light components; a switching circuit (18) for selecting a detection signal from the plurality of detection signals in accordance with a scanning speed with respect to t

Abstract: Methods and systems concerning non-reciprocal sensing paths for a self-mixing interferometry operation are disclosed herein. Optical components may be used to direct light transmit from a light source along an illumination path. The optical components may additionally return light to the light source after being reflected from a target and may direct the returned light along a collection path. The illumination path and the collection path may be at least partially non-reciprocal so that the transmitted light and the returned light follow along partially different paths. Once the received light is received within a cavity of the light source, a self-mixing interferometry operation may be performed and may be used to detect a property of the target in relation to the light source.

Abstract: A measurement apparatus includes a laser apparatus, a branching part that branches a frequency-modulated laser beam output by the laser apparatus into a reference light and a measurement light; a beat signal generation part that generates a beat signal by mixing a reflected light and the reference light, a conversion part that converts the beat signal into a digital signal at a first sampling rate and frequency-analyses it, an extraction part that extracts a signal component corresponding to a cavity frequency from the frequency-modulated laser beam, a digital filter that digitally filters the extracted signal component at a second sampling rate; and a calculation part that calculates a difference in a propagation distance between the reference light and the measurement light.

Abstract: The invention relates to the technical field of radar detection, in particular to a method for radiation calibration of airborne hyperspectral imaging LiDAR system. The method comprises the following steps: S1. A monochromator in a spectrum calibration system emits optical signals of different spectrum values to scan the radar system, thus to obtain the bandwidth and central wavelength of each channel in the radar system; S2. According to the return signal power PR (?, z) in the hyperspectral LiDAR equation and the optical power PRef (?) received by the target surface of the detector in the radar system under experimental conditions, a white diffuse reflection board is taken as the ground object target, and a ranging channel is used to measure the flying height of the radar system, thus to obtain the parameters in the return signal power PR (?, z) and the reflection spectrum ?G (?).

Abstract: Aspects of the present disclosure describe large scale steerable optical switched arrays that may be fabricated on a common substrate including many thousands or more emitters that may be arranged in a curved pattern at the focal plane of a lens thereby allowing the directional control of emitted light and selective reception of reflected light suitable for use in imaging, ranging, and sensing applications including accident avoidance.

Abstract: The present disclosure relates to a fiber encapsulation mechanism for energy dissipation in a fiber amplifying system. One example embodiment includes an optical fiber amplifier. The optical fiber amplifier includes an optical fiber that includes a gain medium, as well as a polymer layer that at least partially surrounds the optical fiber. The polymer layer is optically transparent. In addition, the optical fiber amplifier includes a pump source. Optical pumping by the pump source amplifies optical signals in the optical fiber and generates excess heat and excess photons. The optical fiber amplifier additionally includes a heatsink layer disposed adjacent to the polymer layer. The heatsink layer conducts the excess heat away from the optical fiber. Further, the optical fiber amplifier includes an optically transparent layer disposed adjacent to the polymer layer. The optically transparent layer transmits the excess photons away from the optical fiber.

Abstract: Systems, devices, and methods for performing remote sensing using WMA. Embodiments include modulating an interrogation signal, transmitting the interrogation signal to a remote vibrating target, and receiving, at a first port of a WMA interferometer, a reflected signal. Embodiments also include splitting, by a first beam splitter, the reflected signal into first and second portions propagating down first and second waveguides, delaying, by a delay element, a phase of the reflected signal, and spatially phase shifting the reflected signal. Embodiments may further include splitting, by a second beam splitter, the first and second portions of the reflected signal into third and fourth portions propagating down the first and second waveguides, detecting an intensity difference between a first lobe and a second lobe of the third portion of the reflected signal, and calculating a Doppler frequency based on the intensity difference.

Abstract: Aspects comprise systems implementing 3-D graphics processing functionality in a multiprocessing system. Control flow structures are used in scheduling instances of computation in the multiporcessing system, where different points in the control flow structure serve as points where deferral of some instances of computation can be performed in favor of scheduling other instances of computation. In some examples, the control flow structure identifies particular tasks, such as intersection testing of a particular portion of an acceleration structure, and a particular element of shading code. In some examples, the aspects are used in 3-D graphics processing systems that can perform ray tracing based rendering.

Abstract: A LIDAR system includes a LIDAR chip and local electronics that receive signals from the LIDAR chip. The local electronics are configured to operate one or more components on the LIDAR chip such that the LIDAR chip transmits an optical data signal from the LIDAR chip such that optical data signal includes data generated from the signals received from the LIDAR chip.

Abstract: Described are various configurations for transmitting and receiving optical light using a shared path ranging system. The shared path ranging system can include an optical router (e.g., an optical coupler) coupled to a grating to transmit light to a physical object and receive light reflected by the physical object. The shared path ranging system can include rows of routers and gratings in a two-dimensional configuration to transmit and receive light for ranging purposes.

Abstract: Imaging various regions of the eye is important for both clinical diagnostic and treatment purposes as well as for scientific research. Diagnosis of a number of clinical conditions relies on imaging of the various tissues of the eye. The subject technology describes a method and apparatus for imaging of the back and/or front of the eye using multiple illumination modalities, which permits the collection of one or more of reflectance, spectroscopic, fluorescence, and laser speckle contrast images.

Abstract: A light detection and ranging (LIDAR) system includes an optical source to emit an optical beam, where a local oscillator (LO) signal is generated from a partial reflection of the optical beam from a partially-reflecting surface proximate to the first focal plane, and where a transmitted portion of the optical beam is directed toward a scanned target environment. LIDAR system to focus the LO signal and a target return signal at a second focal plane comprising a conjugate focal plane to the first focal plane. The system may also include a photodetector with a photosensitive surface proximate to the conjugate focal plane to mix the LO signal with the target return signal to generate target information.

Abstract: A light detection and ranging (LIDAR) apparatus includes optical source configured to emit a laser beam in a first direction, a polarization wave plate configured to transform polarization state of the laser beam headed in the first direction toward a target environment, and a reflective optical component to return a portion of the laser beam toward the optical source along a return path and through the polarization wave plate as a local oscillator signal. A polarization selective component to separate light in the return path based on the optical polarization, wherein the polarization selective component refracts orthogonally polarized light along the return path to a divergent path, wherein the polarization selective component is further configured to enable interference between the local oscillator signal and the target signal to generate a combined signal.

Abstract: Methods and systems for performing 3-D LIDAR measurements of objects simultaneously illuminated by two or more beams of light in the far field are described herein. A 3-D LIDAR based measurement device simultaneously emits at least two beams of light into a three dimensional environment from different locations. A portion of the three dimensional environment is simultaneously illuminated by the two or more light beams at a distance of at least five meters from the LIDAR device. However, the two or more light beams do not overlap at a distance less than five meters from the LIDAR device. The beams of light are slightly divergent, having highest intensity at the device and steadily lower intensity further away. By overlapping illumination beams in the far field, but not near the LIDAR device, overall intensity is maintained at moderate levels throughout the field of view of the LIDAR device.

Abstract: A flow rate-velocity sensor device includes a package including a light receiver and a light emitter, a transparent substrate including a light shield, and a flow rate-velocity calculator. The flow rate-velocity calculator includes a receiver, a correction unit, an arithmetic unit, and a transmitter. The receiver receives data on a first power spectrum. The correction unit corrects the data received by the receiver to calculate a second power spectrum. The arithmetic unit calculates at least one of a flow rate or a flow velocity from the second power spectrum calculated by the correction unit. The transmitter transmits, to an external unit, at least one of the flow rate or the flow velocity calculated by the arithmetic unit.

Abstract: A LIDAR system has a transmitter that outputs a system output signal from the LIDAR system. The LIDAR system also includes electronics that control a frequency of the system output signal over a series of cycles. The cycles include multiple data periods. The electronics change the frequency of the system output signal at a first rate during a first one of the data periods. The electronics change the frequency of the system output signal at a second rate during a second one of the data periods. The second rate is different from the first rate.

Abstract: A lidar sensor comprising a laser, an optical sensor, and a processor. The lidar sensor can determine a distance to one or more objects. The lidar sensor can optionally embed a code in beams transmitted into the environment such that those beams can be individually identified when their corresponding reflection is received.

Abstract: Provided is a light detection and ranging (LIDAR) device. The LIDAR device includes: a light source configured to emit a first light beam; a photodetector configured to detect a second light beam, the second light beam being a reflected or scattered light beam of the first light beam reflected or scattered by an object; a diverging member comprising a reflective material configured to diverge the first light beam in various directions by rotating about a rotation axis; and a converging member including an optical element including one or more of a refractive and/or reflective material configured to converge the second light beam from the object and configured to cause the second light beam to be incident on the photodetector.

Abstract: Various examples for multi-tone continuous wave detection and ranging are disclosed herein. In some embodiments, an initial signal is generated using initial radio frequency (RF) tones, and is emitted as a multi-tone continuous wave signal. The initial signal is reflected from a target and received as a reflected signal. Resultant RF tones, including a frequency and a power, are determined from the reflected signal in a frequency domain. A frequency-domain sinusoidal wave is fitted to the resultant RF tones in the frequency domain, and a distance to the target is determined using a modulation of the frequency-domain sinusoidal wave.

Abstract: Described are various configurations for transmitting and receiving optical light using a shared path ranging system. The shared path ranging system can include an optical router (e.g., an optical coupler) coupled to a grating to transmit light to a physical object and receive light reflected by the physical object. The shared path ranging system can include rows of routers and gratings in a two-dimensional configuration to transmit and receive light for ranging purposes.

Abstract: A LIDAR system is described for detecting surroundings, including a laser light source for emitting a laser light, a receiving device for receiving a laser light reflected by the surroundings, and a control device for activating the laser light source, the control device being configured to activate the laser light source for emitting a continuous light beam and to continually modulate the emitted light beam, so that the light beam includes a multitude of successive codes.

Abstract: A method includes generating, using a transmitter, an optical signal for each fiber incoherently combined in a fiber bundle. The method also includes transmitting the optical signal from each fiber as pulses at a target. The method further includes receiving, using a receiver array, the pulses of the optical signals and identifying one or more parameters of the target based on the pulses of the optical signals.

Abstract: An autonomous articulated soil compactor machine can include: a machine frame; at least one cylindrical roller drum rotatably coupled to the machine frame and rotatable about a drum axis oriented generally transverse to a direction of travel of the compactor machine; a first lidar sensor on a front of the machine; a second lidar sensor on a first side of the machine; and a third lidar sensor on a second side of the machine; wherein the first, second and the third lidar sensors are positioned such that 360 degree lidar coverage is provided around the articulated compactor machine.

Abstract: Data transceiving electronic device (100), configured to permit the establishment of at least a communication with at least an electronic device (301; 302) remotely positioned with respect to the data transceiving electronic device (100), said data transceiving electronic device (100) comprises a radio frequency module (105) configured to receive and transmit electronic data on a wireless channel according to at least a predefined first wireless communication standard, and an optical transceiver module (108) in turn comprising at least an optical transmitter (109) and an optical receiver (110); said data transceiving electronic device (100) being configured to select said optical transceiver module (108) as the preferential priority module for the establishment of said communication with said at least one electronic device (301; 302).

Abstract: The invention relates to a method for determining the absolute value of the flow velocity (v) of a particle-transporting medium. At least two measurement laser beams (L_i) with linearly independent, non-orthogonal measurement directions (b_i) are emitted. The measurement laser beams (L_i) scattered at particles are detected and one measurement signal (m_i) is generated in each case for each measurement laser beam (L_i).

Abstract: A draft survey apparatus for gauging a barge by determining a weight of bulk materials loaded and discharged from the barge in water wherein the water level is provided. The draft survey apparatus includes a light source for emitting photons radially outward from the light source, a receiver for receiving the photons reflected off of the barge and surface, the receiver operable to sense a return angle of the photons, and a processor operable to determine a position of the objects and surfaces in three dimensional space based on the return angle of the photons and a time delay of photons between emission and receipt. The processor is operable to determine the weight of the bulk materials on the barge based on a height of barge above the water level.

Abstract: A radar device includes a transmission module and a reception module disposed separately from the transmission module. The transmission module includes: a transmission circuit unit mounted on the first surface of a circuit board; an antenna substrate provided on the second surface side of the circuit board; and a transmission antenna mounted on the second surface of the antenna substrate and not provided in a range on the back surface side of the antenna substrate corresponding to the range in which the circuit board is disposed. The reception module includes: a reception circuit unit mounted on the third surface of a circuit board; an antenna substrate provided on the fourth surface side of the circuit board; and a reception antenna mounted on the fourth surface of the antenna substrate and not provided in a range on the back surface side of the antenna substrate corresponding to the range in which the circuit board is disposed.

Abstract: A transmitting optical system for a LIDAR system is described for illuminating a field of view with light, having a linear light source for generating and outputting primary light in linear form; and having a deflecting optical system that has a lens assemblage in an intermediate image plane of the deflecting optical system for outputting received primary light into the field of view, and has a deflecting mirror, pivotable one-dimensionally around an axis, for receiving primary light from the linear light source and for directing the primary light onto the lens assemblage and, in that context, imaging the linear light source onto the lens assemblage in such a way that the image of the linear light source sweeps over the lens assemblage, or over a part thereof, upon a pivoting motion of the deflecting mirror.

Abstract: A method for retrieval of lost radial velocity in weather radar includes expanding a radial velocity area to non-meteorological echoes including sea clutter and chaff echo using raw radar data for use of a wind field calculation area, correcting radial velocity by replacing the radial velocity determined as noise using a median sign comparison method with a median calculated within a window to which the radial velocity belongs, distinguishing a lost radial velocity area by comparing the corrected radial velocity with radar reflectivity data, and retrieving lost radial velocity using a Velocity Azimuth Display (VAD) fit function representing radial velocity of particles observed along a radar radiation source at a certain elevation in the lost radial velocity area as a function of an azimuth angle. Accordingly, it is possible to improve the quality of calculated wind field using the improved radar radial velocity, and provide more accurate dynamic structure information of the precipitation system.

Abstract: Systems and methods for measuring turbulent gas flux using high-speed vertical wind speed measurements (e.g., on the order of 5-10 Hz or more frequently) and low-speed gas content measurements (e.g., on the order of 5 Hz or less frequently), without the need for the sophisticated and expensive high-speed hardware to separate gas samples (e.g., into accumulation bags) according to updrafts and downdrafts. A time series of high-speed vertical wind speed data is used as a guide to distinguish between updrafts and downdrafts. When vertical wind speed is upward (updraft), the low-speed gas content is recorded into a data structure in one location, or marked with one flag. When vertical wind speed is downward (downdraft), the low-speed gas content is recorded into a different location, or marked with a different flag. Eddy Accumulation or Relaxed Eddy Accumulation computations can be performed using the stored gas content data to determine gas flux.

Abstract: Examples disclosed herein generally relate to systems and methods for detecting the size of a particle in a fluid. In one example, a system for imaging a particle includes a first imaging device. The first imaging device includes a lens and a digital detector. The system further includes a laser source. He laser source is configured to emit a first laser beam and a second laser beam. The digital detector is configured to accumulate a metric of an intensity of an accumulated light that passes through the lens. The accumulated light is scattered from the particle. The accumulated light includes light from the first laser beam and the second laser beam.

Abstract: A light detection and ranging (LIDAR) system encodes a frequency modulation (FM) modulated signal with a time of flight (TOF) signal as a power and frequency modulated signal. The system can emit the power and frequency modulated signal and apply processing to a signal reflection to generate a target point set. The target point set processing can include frequency processing to generate target points based on range and Doppler information, and TOF processing to provide TOF range information. The LIDAR system can include a modulator to AM modulate an FM modulated light signal with an active modulator to provide the TOF signal information with the FM modulated signal as the power and frequency modulated signal.

Abstract: A detector (110) for an optical detection of at least one object (112) is proposed. Further, the invention relates to a method for optical detection of at least one object (112) and to various uses of the detector (110).

Abstract: Aspects relate to mechanisms for increasing the field of view of a spectrometer. An optical device may be configured to simultaneously couple light from different locations (spots) on a sample to the spectrometer to effectively increase the spectrometer field of view. The optical device can include a beam combiner and at least one reflector to reflect light beams from respective spots on the sample towards the beam combiner. The beam combiner can combine the received light beams from the different spots to produce a combined light beam that may be input to the spectrometer.

Abstract: Systems, devices, and methods for performing remote sensing using WMA. Embodiments include modulating an interrogation signal, transmitting the interrogation signal to a remote vibrating target, and receiving, at a first port of a WMA interferometer, a reflected signal. Embodiments also include splitting, by a first beam splitter, the reflected signal into first and second portions propagating down first and second waveguides, delaying, by a delay element, a phase of the reflected signal, and spatially phase shifting the reflected signal. Embodiments may further include splitting, by a second beam splitter, the first and second portions of the reflected signal into third and fourth portions propagating down the first and second waveguides, detecting an intensity difference between a first lobe and a second lobe of the third portion of the reflected signal, and calculating a Doppler frequency based on the intensity difference.

Abstract: A coaxial-macro-scanner-system, including a light-source, a light-detector, and a rotatable-mirror-system to optically isolate an optical-path between the light-source and light-detector, the rotatable-mirror-system emitting a transmitting-light-beam, generated by the light-source, with a first-mirror in a predefined-plane into an environment, and to receive a receiving-light-beam, representing components of the transmitting-light-beam reflected/dispersed by the environment, with a second-mirror in the same-plane and to reflect it onto the light-detector, both the first-mirror, the second-mirror and an axis of rotation about which the second-mirror is rotated being aligned at a right-angle to the predefined-plane, the first-mirror being aligned at a right-angle to the predefined-plane and being in a region of the rotation-axis of the second-mirror so that the first-mirror and the second-mirror rotate about the common-rotation-axis, and an angle under which the first-mirror and the second-mirror are disposed r

Abstract: An optical fiber characteristics measuring apparatus includes: a light source that outputs frequency-modulated continuous wave of light; a first optical branching unit that branches the continuous light into pump light and reference light; a second optical branching unit that outputs backscattered light generated by making the pump light incident from one end of an optical fiber to be measured, wherein the backscattered light is Brillouin scattering in the optical fiber; a detector that detects interference light of the backscattered light and the reference light; a measuring unit that measures characteristics of the optical fiber by using a detection signal output from the detector; and a controller that controls the light source to change modulation frequency of the continuous light in units of one period or half a period of a modulation period corresponding to the modulation frequency.

Abstract: The present disclosure provides a compressed ultrafast imaging velocity interferometer system for any reflector, comprising a light source and target system, an etalon interference system, a compressed ultrafast imaging system, a timing control system and a data processing system. An imaging device in the traditional imaging velocity interferometer system for any reflector is replaced by a compressed ultrafast imaging system, a compressed ultrafast Photography (CUP) is introduced in an imaging process, multi-frame images, i.e.

Abstract: An optical air data system for an air vehicle includes a LIDAR module and a data processing module. The LIDAR module is configured to emit at least three laser beams, not all located in a common plane, and perform LIDAR measurements of a backscattered component of each of the laser beams. The data processing module includes a processor and machine-readable instructions that, when executed by the processor, processes the LIDAR measurements to determine at least one optically-based air data parameter. The overlap between the laser beams and one or more fields of view of the LIDAR module may be within two meters from the LIDAR module to determine the at least one optically-based air data parameter at short range from the air vehicle.

Abstract: A wind flow sensing system for determining wind flow at a set of different altitudes above a terrain is provided, The wind flow sensing system comprises an input interface configured to receive a set of measurements of radial velocities at line-of-site points above the terrain for each of the altitudes, and a processor configured to estimate velocity fields for each of the altitudes based on data assimilation of the velocity fields above an approximation of the shape of the terrain with a set of one or multiple convex shapes to fit the measurements of radial velocities and estimate horizontal velocities at each of the altitudes as a horizontal projection of the corresponding radial velocities corrected with corresponding horizontal derivatives of vertical velocities of the estimated velocity fields. The wind flow sensing system further comprises an output interface configured to render the estimated horizontal velocities at each of the altitudes.

Abstract: The laser radar device includes: a modulated light generator configured to generate modulated laser light using frequency modulation based on a control parameter; an optical combiner configured to combine the received light and the local light to generate interference light; a photodetector configured to detect the interference light and output an electrical signal; a frequency-to-voltage converter configured to convert the electrical signal into a voltage signal; a characteristic calculator configured to measure a characteristic value of the voltage signal; an evaluator configured to evaluate, on a basis of the characteristic value, whether a center frequency of a spectrum of a return signal component is within a range of a demodulation band of a demodulation circuit; and a parameter setting unit configured to change the control parameter when it is evaluated that the center frequency is not within the range of the demodulation band.

Abstract: One or more devices, systems, methods and storage mediums for optical imaging medical devices, such as, but not limited to, Optical Coherence Tomography (OCT), single mode OCT, and/or multi-modal OCT apparatuses and systems, and methods and storage mediums for use with same, for performing automated polarization control, polarization diversity and/or balanced detection are provided herein. One or more embodiments may achieve polarization diversity and balanced detection (or photo-detection) under any imaging circumstances. One or more embodiments, may achieve polarization control functionality regardless of whether such control is automatic or manual. Additionally, one or more embodiments may achieve automated polarization control, may achieve balanced detection (or photo-detection), and/or may address potential disturbances, such as, but not limited to, polarization drift over time, temperature and/or mechanical perturbations or variations.

Abstract: An aircraft and method of operating an aircraft. A sensor measures an air velocity at a location a selected distance from the aircraft. A processor determines an effect of the air velocity on an accuracy metric of a first flight course of the aircraft, changes from the first flight course to a second flight course when the accuracy metric of the first flight course meets a threshold and operates the aircraft according to the second flight course.

Abstract: A distance measuring method and device, wherein a first and a second laser radiation are generated so that the first laser radiation has a first frequency modulation and the second laser radiation has a second frequency modulation, wherein at least in sections a time derivative of the first frequency modulation is different from a time derivative of the second frequency modulation. In accordance with the invention the first and the second laser radiation are generated by modulating a base radiation by means of an electro-optical modulator, so that an output radiation comprising a carrier component and a plurality of sideband components is produced, wherein a first sideband component provides the first laser radiation and a second sideband component provides the second laser radiation.

Abstract: A display apparatus configured to be coupled to a movable object includes at least a first laser sensor module and a display device configured to display a field-of-view. The first laser sensor module is configured to determine, by self mixing interference measurements, movements of the movable object with respect to a reference object mechanically coupled to the movable object. The first laser sensor module is configured to emit at least three measurement beams in three different spatial directions to the reference object when the display apparatus is coupled to the movable object and the first laser sensor module is configured to determine velocity vectors or distances collinear to the spatial directions. The display device is configured to integrate at least one virtual object in the field-of-view in accordance with the determined movements of the movable object.

Abstract: A method of measuring a particle density of particles includes emitting, by a laser, a laser beam directed to a mirror, redirecting the laser beam by the mirror with a predetermined periodic movement, and focusing the laser beam to a detection volume by an optical imaging device. The method further includes determining a self mixing interference signal of an optical wave within a laser cavity if the self mixing interference signal is generated by laser light of the laser beam reflected by at least one of the particles and suppressing a false self mixing interference signal for particle detection if the self mixing interference signal is caused by a disturbance in an optical path of the laser beam. The false self mixing signal caused by the disturbance in the optical path of the laser beam is suppressed in a defined range of angles of the mirror during the periodic movement.