WO2002042792A1 - Systeme et procede de mesure de la profondeur d'eau - Google Patents

Systeme et procede de mesure de la profondeur d'eau Download PDF

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Publication number
WO2002042792A1
WO2002042792A1 PCT/SE2001/002515 SE0102515W WO0242792A1 WO 2002042792 A1 WO2002042792 A1 WO 2002042792A1 SE 0102515 W SE0102515 W SE 0102515W WO 0242792 A1 WO0242792 A1 WO 0242792A1
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WO
WIPO (PCT)
Prior art keywords
radiation
laser
reflected
value
depth
Prior art date
Application number
PCT/SE2001/002515
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English (en)
Inventor
Rolf ENGSTRÖM
Andreas Axelsson
Original Assignee
Airborne Hydrography Ab
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Airborne Hydrography Ab filed Critical Airborne Hydrography Ab
Priority to AU2002215279A priority Critical patent/AU2002215279A1/en
Publication of WO2002042792A1 publication Critical patent/WO2002042792A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/06—Systems determining position data of a target
    • G01S17/08—Systems determining position data of a target for measuring distance only
    • G01S17/10—Systems determining position data of a target for measuring distance only using transmission of interrupted, pulse-modulated waves
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C13/00—Surveying specially adapted to open water, e.g. sea, lake, river or canal
    • G01C13/008—Surveying specially adapted to open water, e.g. sea, lake, river or canal measuring depth of open water
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/88—Lidar systems specially adapted for specific applications
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/497—Means for monitoring or calibrating

Definitions

  • the invention concerns a system and a method for measuring distance by laser means.
  • the invention is especially intended for laser bathymetry.
  • a number of different techniques are available to choose among for making hydrographic measurements such as water-depth measurements, depending on the particular application.
  • the technique that formerly dominated is known as multibeam bathymetry. This technique is based on sending multiple parallel "sound beams" down into the water and then recording them. The measurements are thus made using the same principles as in echo sounding.
  • laser bathymetry has been developed in which the measurements are made using laser light from a flying platform rather than sound from a vessel-based platform. These two techniques complement rather than compete with one another, since laser bathymetry is best suited to shallow water near land, while multibeam measurements are more effective in deep water.
  • Laser bathymetry systems can be mounted in both helicopters and aircraft, and may include a laser that emits pulsed radiation in the infrared spectrum while simultaneously emitting pulsed radiation in the visible spectrum, preferably green light.
  • the infrared radiation is reflected from the water surface, while a substantial portion of the visible light penetrates down into the water and is reflected from the bottom.
  • the system further contains a receiver arranged so as to receive a portion of the reflected radiation and record the intensity of the received radiation.
  • a calculating unit connected to the receiver calculates the time difference between the reception of the radiation reflected from the water surface and the radiation reflected from the bottom, whereupon the water depth is calculated as half the time distance multiplied by the speed of light, with correction for the angle of incidence of the radiation relative to the water surface.
  • the laser bathymetry system it is possible to quickly measure depths over a relatively large area, since a helicopter can typically fly at 30 - 130 knots at a height of 200 - 500 meters above the surface, thereby allowing the laser beam to sweep an area of 100 - 200 meters transverse to the direction of flight.
  • Water depths of some twenty meters can typically be measured using the laser bathymetry system.
  • the measurable depth is limited by how much reflected laser radiation the laser bathymetry system receiver receives relative to the received ambient noise, which consists primarily of solar radiation. Because the radiation is damped exponentially in the water, due to absoi tion and scattering, only a very small part of the light striking the surface will return to the receiver. To attain optimum range, the following factors may be taken into account.
  • the measurements can be made when the water quality is optimal;
  • the receiver can be designed so that it provides the highest possible sensitivity;
  • refined algorithms can be used in the receiver to detect small light reflections in the background light noise;
  • the flights can be made at low altitude and, fifth, the laser power can be high and the beam divergence low, thereby ensuring a high laser energy density at the water surface.
  • IEC 60825 is the international standard for classifying lasers and laser safety.
  • the standard has a number of local variants, EN 60825 for Europe and SS-EN 60825 for Sweden.
  • the standard specifies the highest permissible energy density and power density per square meter to ensure the safety of the naked eye.
  • the laser can also be treated as a point source. In such cases the provisions of the Swedish State Radiation Protection Institute's regulations regarding lasers, SSI FS 1993:1 or later versions, set forth maximum permissible exposures for various wavelengths, expressed in joules/m . During normal laser use, the laser power is adjusted so that the energy density and power density are kept within the permissible values.
  • the system contains a built-in safety function that monitors to ensure that the permissible values are not exceeded.
  • the laser is turned off automatically.
  • a person located on the shore of a lake or ocean who is using binoculars is exposed to substantially higher laser energy and power levels than with just the naked eye, since the energy density received by the eye increases by the square of the binocular magnification power.
  • a laser bathymetry system that is safe to the naked eye would thus not be safe for eyes using binoculars.
  • the laser bathymetry system operator manually turns off the laser whenever the airplane/helicopter passes over areas where the presence of people who might be using binoculars is suspected. No depth measurements are made during these temporary shutdowns, thus creating areas in which no depth measurements are performed. In lightly trafficked open waters such unmeasured areas in which supplemental measurements are necessary will be small, and few in number.
  • many unmeasured areas in which the laser must be turned off will occur in areas of populated land or dense boat traffic. It may be impossible, or at least extremely time-consuming, to complete the measurements for many such unmeasured areas.
  • One purpose of the invention is to provide, in comparison with the prior art, a better way to make laser bathymetry measurements over areas in which it may be assumed that people are present, at least in certain locations, and that takes the aforementioned problems into account.
  • a laser bathymetry system according to claim or 1 and 2.
  • the system is arranged so as to continuously determine an energy density, power density or corresponding value of a laser in a cross-section of the laser beam at a specified distance from a laser.
  • the system is further arranged so as to compare the determined power density with a selected threshold value.
  • the threshold value is chosen so that the permissible energy and/or power density values for the laser wavelength(s) used, as specified in the applicable standards, will not be exceeded.
  • the threshold value is preferably chosen with a certain margin.
  • the system is also arranged so as to indicate whether the threshold value has been exceeded, e.g. in that the laser is turned off when this occurs.
  • the system is characterized in that it includes means for selecting one from among a set of at least two selectable threshold values as the selected threshold value, and means for adjusting the system for the threshold value selected.
  • One of the threshold values is chosen to ensure the safety of the naked eye, while the second threshold value ensures the safety of an eye equipped with binoculars.
  • the threshold values can be selected either manually or automatically on the basis of preset criteria. Given that, in the context of distance measuring, the possibilities of receiving and detecting a reflected laser beam degrade dramatically with increasing beam divergence, it is primarily the output power of the laser that is adjusted when a new threshold value is selected. This may be achieved either by inducing the laser to adjust the pumping of the laser medium or, for the lower threshold value, by diverting a portion of the laser beam.
  • the above described laser bathymetry system is installed in an aircraft such as an ai ⁇ lane or a helicopter.
  • the laser is arranged so as to emit laser radiation at two frequencies, wherein the radiation at the first frequency is mainly reflected from the water surface, while the radiation at the second frequency mainly penetrates through the water surface and is reflected from the bottom.
  • one single laser radiation frequency is used, the frequency being chosen so that one part of the radiation is reflected in the ocean or lake surface and the other part of the radiation penetrates the water surface and is reflected in the bottom of the lake or ocean.
  • the laser bathymetry system is equipped with means for receiving said surface- and bottom- reflected radiation, and means for processing the received radiation to determine a time difference between the reception of the radiation reflected from the surface and the radiation reflected from the bottom. These processing means then calculate the water depth on the basis of the time difference.
  • the system is adjustable for a selected power density or corresponding value of the laser beam at a specified distance from the laser, e.g. the point of reflection at the water surface.
  • the system is characterized in that it includes means for selecting one from among a set of at least two selectable threshold values as the selected value, and means for adjusting the system for the selected threshold value.
  • the system is further arranged so as to continuously determine the power density or corresponding value of the laser beam at the specified distance from the laser in order to confirm that the laser radiation is not exceeding the current selected value.
  • one of the values in the set is predefined as the normal setting, and the selecting means are arranged in such a way that, upon actuation, the second value will be selected for a predetermined length of time, after which the means will automatically resume the normal setting.
  • the invention further includes a method for laser bathymetry measurements according to claim .
  • the invention further includes methods for measuring the depth of an ocean or lake in accordance with claim 7 or 8.
  • a lower laser power will instead be used for such areas, so that eye safety is ensured, even, if binoculars are used.
  • the lower laser power entails a reduction of the maximum measurement depth. Because people are often present in areas near shore, which are seldom especially deep, full bottom coverage can often be achieved, even with the lower laser energy level.
  • Figure 1 shows an example of a laser bathymetry system according to the invention.
  • Figure 2 shows an alternative example of a laser bathymetry system according to the invention.
  • Figure 3 shows a diagram that illustrates the received radiation in the system in Figure 1, including a receiver.
  • reference number 1 indicates a helicopter- or ai ⁇ lane-based laser bathymetry system for measuring water depths in oceans, lakes, rivers or other watercourses.
  • the system 1 contains a laser 2.
  • Aiming devices (not shown) are placed in front of the laser 2 to aim the laser beam at the water surface at a selected angle.
  • the aiming devices consist of, e g. mirrors that are rotatable in at least one direction and positioned in the beam path of the laser.
  • the laser beam is caused, by means of the aiming devices, to sweep over an area transverse to the direction of helicopter flight.
  • the laser emits monochromatic pulsed radiation at wavelengths within the infrared spectrum while simultaneously emitting monochromatic pulsed radiation within the visible spectrum, preferably green light.
  • the infrared radiation is reflected from the water surface, while a significant portion of the green light penetrates down into the water and is reflected from the bottom.
  • one single laser frequency is used, the frequency being chosen such that one part of the radiation is reflected in the water surface and another part of the radiation penetrates the water surface and is reflected in the bottom.
  • the system 1 includes a receiver 3 arranged so as to receive the reflected radiation and record its intensity.
  • Figure 3 shows the thus recorded pulse response with two intensity peaks.
  • the first peak represents the reflection from the water surface, while the second peak represents the reflection from the bottom.
  • a calculating unit 4 connected to the receiver 3 calculates the time difference between the intensity peaks, whereupon the water depth is calculated as half the time difference multiplied by the speed of light, with correction for the angle of incidence of the beam relative to the water surface.
  • the way in which an algorithm could be implemented to perform the foregoing calculation will be obvious to one skilled in the art.
  • the radiation reflected from the surface is damped insignificantly in the course of its laser/water surface/receiver path, while the laser radiation reflected from the bottom will be damped considerably, as shown in Figure 3.
  • the system 1 includes a switch 5 in the form of, .g. a conventional manually operable switch that is switchable between two setting positions.
  • the switch controls primarily the laser power from the system 1.
  • the beam divergence of the laser beam is also controlled. In the first setting position, the power is selected for the given beam divergence to achieve the maximum permissible exposure for the wavelength used, as specified in joules per square meter in accordance with applicable regulations.
  • the power level that is permissible for use at the first setting position thus depends on the divergence of the laser beam, since said divergence determines the surface area covered by the pulse at the water surface. Divergence levels of from 2- 15 mRad are relevant in a laser bathymetry context.
  • the radiation level is such that eye safety is maintained, including for binocular-aided eyes.
  • the maximum exposure must be below the maximum permissible exposure for the naked eye divided by the square of the binocular magnification power.
  • the only remaining alternative is to lower the laser power so that the maximum permissible exposure (expressed in joules/m ) is appropriate for the binocular-aided eye.
  • Conventional "consumer binoculars" normally offer magnifications of lOx or less. Taking this into account, the power level in one embodiment is 100 times lower in the second setting position than in the first.
  • the switch 5 controls a beam splitter 6 in such a way that, when the switch 5 is set to its second, low-energy position, the beam splitter 6 is kept in the beam path in front of the laser and, when the switch 5 is set to its first, high-energy position, the beam splitter 6 is kept outside the beam path.
  • the low-energy setting, in which the beam splitter 6 is kept in the beam path in front of the laser 2, is illustrated in Figure 1.
  • a mechanical device of conventional type (not shown) supports the beam splitter 6 and is arranged so as to move the beam splitter 6 into/out of the beam path when the switch 5 is moved from one setting position to the other.
  • the beam splitter 6 is designed to split the incident light into two components, so that the preponderance of the power (99% in the example above) is damped by a beam damper (not shown) in the low- energy setting.
  • the beam splitter consists of a conventional semitransparent mirror, whose properties are such that it reflects 99% of the radiation while allowing 1% to pass through.
  • a variable wave plate 7 is arranged in the beam path in front of the laser 2.
  • the wave plate consists of, e.g. a birefractive crystal capable of changing the polarization of incident light.
  • the switch 5 has an operative connection with the wave plate 7 via a control unit 8.
  • the control unit is arranged so that, when the switch is set to its first, high-power position, it controls the wave plate so that the polarization of the linearly polarized light remains unchanged after its passage through the wave plate 7.
  • the linearly polarized light striking the wave plate thus leaves the wave plate in the form of linearly polarized light of the same intensity as the incident light.
  • the control unit is further arranged so that, when the switch 5 is set to its second, low-power position, it controls the shift in the wave plate 7 so that the linearly polarized light leaves the wave plate in the form of circularly polarized or elliptical light.
  • a polarization splitter 9 that is designed so that a first polarization direction, which is coincident with that of the linearly polarized beam in the high-power setting, passes unaffected through the splitter 9, while a second polarization direction, which is perpendicular to the first, is diverted.
  • the thus diverted beam is then removed in that, e.g. it is allowed to strike an absorbent material (not shown).
  • Control of the wave plate 7 thus enables control of the proportion of the beam that will be polarized in the second polarization direction so as to thereby enable control of the final degree of disengagement from full power in the first setting position to low-power in the second setting position.
  • the switch 5 is directly operatively connected with the laser 2 to control it to pump the laser medium more when the switch is switched to its high- power setting, and to pump the laser medium less when the switch is switched to its low-power setting.
  • the laser power is adjusted so that the energy density and power density are kept within the permissible values.
  • a safety function that monitors to ensure that the permissible values are not exceeded. The laser is shut off automatically if these values are exceeded.
  • the safety function is designed in such a way that the calculating unit 4 is arranged so as to measure not only the depth, but also the altitude of the airplane/helicopter above the water. This is accomplished by simple means in that the calculating unit measures the time that elapses until an emitted infrared pulse of radiation reflected from the water surface is received, correcting the measured value for the angle of incidence of the beam relative to the water surface. The pulse energy of the laser is also measured.
  • the calculating unit is arranged, given that the beam divergence is known, so as to calculate the energy density at the water surface.
  • the system shuts off the laser if the calculated energy density value exceeds a predefined threshold value in the calculating unit 4.
  • This threshold value is naturally determined by the standards noted above (e.g. the Swedish State Radiation Protection Institute's regulations regarding lasers, SSI FS 1993:1) and by the power setting in which the system is operating (high- power/low-power).
  • there is predefined in the calculating unit 4 one threshold value for the infrared beam and another for the visible light in the high-power setting, as well as one threshold value for the infrared beam and another for the visible light in the low-power setting.
  • threshold values are based on direct exposure. However, approximating the power density to which the eye is exposed in connection with direct emission as the power density that the beam possesses at the water surface does provide a good approximation.
  • the switch 5 is manually switchable between two setting positions.
  • the switch 5 can alternatively have a normal setting and be arranged so that, when actuated, it deviates from its normal setting for a predetermined length of time before resuming the normal setting.
  • a number of such manually switchable switches is currently available on the market.
  • the high-power setting constitutes the normal setting, while the low- power setting constitutes the deviant setting.
  • the switch 5 has a third setting position, AUTO (not shown).
  • the control unit 8 is arranged so as to receive control information from the calculating unit 4.
  • the control information consists of measured depth information from the laser bathymetry system 1.
  • the control unit 8 is configured to compare the measured depth to a preselected depth value that is predefined in the calculating unit 4. When the measured depth exceeds the preselected depth, the control unit is arranged so as to send to the wave plate 7 a control signal that is equivalent to the high-power setting signal, and to send a control signal equivalent to the low-power setting signal to the wave plate 7 when the depth falls below the preselected value. This provides a way of ensuring that no more laser power is used than is necessary.
  • a position-indicating device such as a GPS receiver is arranged in connection with the laser bathymetry system.
  • a memory is operatively connected to the control unit.
  • the memory consists of, e.g. a table of coordinate intervals, preferably in two dimensions, within which intervals measurements are to be made in the high-power setting, and a table of coordinate intervals within which measurements are to be made in the low-power setting.
  • the control unit in this embodiment is arranged so as to receive, in the AUTO setting, position signals from the GPS receiver, and to compare the received position with the interval specified in the tables in the memory, and to select the high-power/low-power setting based on the table in which the current position is found.
  • this interval is represented as a zone on a map image.
  • the distance to land is determined based on the current position and a map image, whereupon the control unit selects the high-power setting if the distance exceeds a predetermined distance, and selects the low-power setting if the distance is less than the predetermined distance.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Electromagnetism (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Optical Radar Systems And Details Thereof (AREA)

Abstract

La présente invention concerne un procédé et un système de bord permettant de mesurer la profondeur d'un océan ou d'un lac. Des moyens d'émission d'un rayonnement laser (2) sont conçus pour émettre un rayonnement laser de telle façon qu'une première partie du rayonnement soit réfléchie par la surface de l'eau et qu'une deuxième partie du rayonnement traverse la surface de l'eau et soit réfléchie par le fond. Des moyens de réception (3) sont conçus pour recevoir ce rayonnement réfléchi, et des moyens de traitement (4) sont conçus pour traiter les parties de rayonnement reçues en vue de déterminer une différence de temps entre la réception du rayonnement réfléchi à la surface et la réception du rayonnement réfléchi par le fond. La profondeur de l'eau est alors calculée à partir de cette différence de temps. Des moyens (5) permettent de sélectionner une valeur dans un ensemble constitué d'au moins deux densités de puissance ou valeurs correspondantes sélectionnables du rayonnement laser à une distance spécifique du laser, et le système est ajusté pour une valeur sélectionnée.
PCT/SE2001/002515 2000-11-21 2001-11-13 Systeme et procede de mesure de la profondeur d'eau WO2002042792A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2002215279A AU2002215279A1 (en) 2000-11-21 2001-11-13 System and method for measuring water depth

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE0004259-8 2000-11-21
SE0004259A SE0004259L (sv) 2000-11-21 2000-11-21 System och metod för avståndsmätning medelst laser

Publications (1)

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WO2002042792A1 true WO2002042792A1 (fr) 2002-05-30

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PCT/SE2001/002515 WO2002042792A1 (fr) 2000-11-21 2001-11-13 Systeme et procede de mesure de la profondeur d'eau

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AU (1) AU2002215279A1 (fr)
SE (1) SE0004259L (fr)
WO (1) WO2002042792A1 (fr)

Cited By (12)

* Cited by examiner, † Cited by third party
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WO2003064970A1 (fr) * 2002-02-01 2003-08-07 Tenix Lads Corporation Pty Ltd Appareil et procede pour faire osciller un faisceau laser de lumiere emis a l'interieur d'un champ de vision (fov) dans un systeme de reception de lumiere
WO2003065068A1 (fr) * 2002-02-01 2003-08-07 Tenix Lads Corporation Pty Ltd Appareil pour mesurer la profondeur de l'eau, comprenant un ensemble de balayage piezoelectrique
WO2004099820A1 (fr) * 2003-05-06 2004-11-18 Airborne Hydrography Ab Procede, systeme et support de stockage concernant la mesure de structure d'objets
DE102007053852A1 (de) * 2007-11-12 2009-05-14 Robert Bosch Gmbh Vorrichtung zur optischen Distanzmessung
WO2009115343A1 (fr) * 2008-03-20 2009-09-24 Cedes Ag Détecteur destiné à la surveillance d'une zone de surveillance
CN109405809A (zh) * 2018-10-24 2019-03-01 中国电力科学研究院有限公司 一种变电站洪水水深检测方法与系统
US10684362B2 (en) 2011-06-30 2020-06-16 The Regents Of The University Of Colorado Remote measurement of shallow depths in semi-transparent media
CN111637950A (zh) * 2020-05-19 2020-09-08 哈尔滨工程大学 一种基于红外测距的室内防漏水系统
CN113815555A (zh) * 2021-10-13 2021-12-21 东风汽车集团股份有限公司 基于路面积水的汽车底盘自动升降方法及系统
US11231502B2 (en) 2011-06-30 2022-01-25 The Regents Of The University Of Colorado Remote measurement of shallow depths in semi-transparent media
US11313678B2 (en) 2011-06-30 2022-04-26 The Regents Of The University Of Colorado Remote measurement of shallow depths in semi-transparent media
US11933899B2 (en) 2011-06-30 2024-03-19 The Regents Of The University Of Colorado Remote measurement of shallow depths in semi-transparent media

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WO1997006450A1 (fr) * 1995-08-09 1997-02-20 Saab Dynamics Aktiebolag Procede servant a mesurer des profondeurs d'eau relativement limitees particulierement au voisinage du littoral et de bords de lacs
US5837996A (en) * 1994-12-02 1998-11-17 Keydar; Eytan Eye protection system wherein a low power laser controls a high power laser

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Publication number Priority date Publication date Assignee Title
US4277167A (en) * 1976-08-25 1981-07-07 The United States Of America As Represented By The Secretary Of The Navy Depth mapping system
WO1989007771A1 (fr) * 1988-02-10 1989-08-24 Messerschmitt-Bölkow-Blohm Gesellschaft Mit Beschr Appareil optique de mesure de distance
US5451765A (en) * 1994-10-31 1995-09-19 Gerber; Peter Eye safety protection system for a laser transmission system wherein laser energy scattered back along the beam path is detected
US5837996A (en) * 1994-12-02 1998-11-17 Keydar; Eytan Eye protection system wherein a low power laser controls a high power laser
DE4444828A1 (de) * 1994-12-15 1996-06-20 Bayerische Motoren Werke Ag Sicherheitseinrichtung für ein Laser-Abstandsmeßsystem
WO1997006450A1 (fr) * 1995-08-09 1997-02-20 Saab Dynamics Aktiebolag Procede servant a mesurer des profondeurs d'eau relativement limitees particulierement au voisinage du littoral et de bords de lacs

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003064970A1 (fr) * 2002-02-01 2003-08-07 Tenix Lads Corporation Pty Ltd Appareil et procede pour faire osciller un faisceau laser de lumiere emis a l'interieur d'un champ de vision (fov) dans un systeme de reception de lumiere
WO2003065068A1 (fr) * 2002-02-01 2003-08-07 Tenix Lads Corporation Pty Ltd Appareil pour mesurer la profondeur de l'eau, comprenant un ensemble de balayage piezoelectrique
WO2003065069A1 (fr) * 2002-02-01 2003-08-07 Tenix Lads Corporation Pty Ltd Appareil et procede de mesure de profondeur d'eau au moyen d'un recepteur commande
US6997568B2 (en) 2002-02-01 2006-02-14 Tenix Lads Corporation Pty Ltd Apparatus for measurement water depth including a piezoelectric scanning assembly
US7248341B2 (en) 2002-02-01 2007-07-24 Tenix Lads Corporation Pty Ltd Apparatus and method for oscillating a transmitted laser beam of light within the field of view (FOV) of a light receiving system
WO2004099820A1 (fr) * 2003-05-06 2004-11-18 Airborne Hydrography Ab Procede, systeme et support de stockage concernant la mesure de structure d'objets
DE102007053852A1 (de) * 2007-11-12 2009-05-14 Robert Bosch Gmbh Vorrichtung zur optischen Distanzmessung
US8395759B2 (en) 2007-11-12 2013-03-12 Robert Bosch Gmbh Device for optical distance measurement
WO2009115343A1 (fr) * 2008-03-20 2009-09-24 Cedes Ag Détecteur destiné à la surveillance d'une zone de surveillance
US9250326B2 (en) 2008-03-20 2016-02-02 Cedes Ag 3-D sensor with adaptive transmitting power for monitoring an area
US11313678B2 (en) 2011-06-30 2022-04-26 The Regents Of The University Of Colorado Remote measurement of shallow depths in semi-transparent media
US10684362B2 (en) 2011-06-30 2020-06-16 The Regents Of The University Of Colorado Remote measurement of shallow depths in semi-transparent media
US11231502B2 (en) 2011-06-30 2022-01-25 The Regents Of The University Of Colorado Remote measurement of shallow depths in semi-transparent media
US11624814B2 (en) 2011-06-30 2023-04-11 The Regents Of The University Of Colorado Remote measurement of shallow depths in semi-transparent media
US11725937B2 (en) 2011-06-30 2023-08-15 The Regents Of The University Of Colorado, A Body Corporate Remote measurement of shallow depths in semitransparent media
US11933899B2 (en) 2011-06-30 2024-03-19 The Regents Of The University Of Colorado Remote measurement of shallow depths in semi-transparent media
CN109405809A (zh) * 2018-10-24 2019-03-01 中国电力科学研究院有限公司 一种变电站洪水水深检测方法与系统
CN109405809B (zh) * 2018-10-24 2022-07-12 中国电力科学研究院有限公司 一种变电站洪水水深检测方法与系统
CN111637950A (zh) * 2020-05-19 2020-09-08 哈尔滨工程大学 一种基于红外测距的室内防漏水系统
CN113815555A (zh) * 2021-10-13 2021-12-21 东风汽车集团股份有限公司 基于路面积水的汽车底盘自动升降方法及系统

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