Abstract: A camera monitors positions on an external object having a beacon (1(i), i=1, 2, . . . , I; 130; 430) attached to it. The apparatus has at least one image sensor (120; 321, 322; 420; 520), an imaging optical element (101) for projecting light on the image sensor (120), and a processing unit (9). The imaging optical element (101) may be non-refractive and receives a light beam (5(i); 131) transmitted from the beacon (1(i); 130; 430) and transfers the light beam (5(i); 131) to the image sensor (120; 321, 322; 420; 520). The image sensor (120; 321, 322; 420; 520) forms image data based on the received light beam (5(i); 131) and background light. The processing unit (9) processes the image data such that it filters image data components relating to the background light and renders image data components relating to the light beam.

Abstract: A communication unit (20) configured for wireless optical communication underwater, and including a communication transceiver (24), a housing (22), an adjustment mechanism (28), and a processor (40). The transceiver is accommodated in the housing, and includes a signal detector configured to receive an optical communication signal (50) approaching the unit within a main detection lobe centred on a receiver directivity axis (Ar), and/or includes a signal generator configured to emit an optical communication signal (52) via a main emission lobe centred on a transmitter directivity axis (At). The adjustment mechanism is configured to adjust orientation(s) of the receiver and/or transmitter directivity axes relative to the housing. The processor is configured to determine a directional coordinate (?i, ?i) for an approaching light signal (50, 54), and to control the adjustment mechanism to automatically adjust and align the orientation of the directivity axes with the determined directional coordinate.

Abstract: Apparatus for determining a spatial property in a 3D-space, wherein the apparatus comprises a physical pointer, a camera and a position and orientation measurement system, wherein a first object in the 3D-space comprises a pattern on it, wherein the physical pointer is configured to contact a surface area of a second object in the 3D-space, wherein the camera is configured to capture, at a position of the camera with respect to the first object, image data comprising an image of the pattern; wherein the position and orientation measurement system is configured to determine a heading, position, verticality, attitude, and/or inclination of the camera based on the image of the pattern, and determine, based on the determined heading, position, verticality, attitude, and/or inclination of the camera and a relative position of the physical pointer with respect to the camera, the spatial property of the surface area by the physical pointer.

Abstract: A system for monitoring survey reflectors arranged at a plurality of locations on an object, having: a camera, including: one or more light sources arranged to illuminate a field in space corresponding to at least 10% of a field of view of the camera, preferably the whole field of view; an image sensor receiving light beams from reflections of the beam by the survey reflectors and providing data; a body with an optical entry system, the image sensor located on a first side and the light source on a second side of the body; and a processing unit processing the data. The processing unit is configured to determine locations of the survey reflectors from the image sensor data and detect movement of the survey reflectors based on a comparison of the determined locations with previously determined locations.

Abstract: A method and system for locating a high-intensity target light source (26) from an elevated observation location (Po), for instance in an aircraft. The target light source is located at/near an earth surface portion (30) and amongst reference light sources (16, 24, 25) arranged along the surface portion. This target light source emits light (28) with a peak radiant intensity that exceeds the intensity of the reference light sources by at least one order of magnitude. The method includes: acquiring, with an image recording device located at the observation location, images of the light and light emitted the reference light sources; comparing the images and a digital ground map (50) that includes representations of the surface portion and of structures (20, 22) associated with the reference light sources, and estimating a location (Pt) of the target light source relative to the reference light sources, based on the comparison.

Abstract: A communication unit (20) configured for wireless optical communication underwater, and including a communication transceiver (24), a housing (22), an adjustment mechanism (28), and a processor (40). The transceiver is accommodated in the housing, and includes a signal detector configured to receive an optical communication signal (50) approaching the unit within a main detection lobe centred on a receiver directivity axis (Ar), and/or includes a signal generator configured to emit an optical communication signal (52) via a main emission lobe centred on a transmitter directivity axis (At). The adjustment mechanism is configured to adjust orientation(s) of the receiver and/or transmitter directivity axes relative to the housing. The processor is configured to determine a directional coordinate (?i, ?i) for an approaching light signal (50, 54), and to control the adjustment mechanism to automatically adjust and align the orientation of the directivity axes with the determined directional coordinate.

Abstract: An observation unit (30) for underwater deployment on/in a submerged earth layer (12) or structure. The unit comprises a housing (32), a light source (36), an underwater imaging device (40), a processor device (44), and a communication device (35). The housing supports the underwater observation unit relative to the submerged layer or structure. The light source is fixed to the housing, and configured to emit light into the unit's surroundings. The imaging device is attached to the housing, and configured to acquire image data of a second light source located within a FOV of the camera that covers the surroundings of the unit. The processor device is configured to determine positional data of the second light source relative to the imaging device, from the image data. The communication device is configured to transmit the positional data to another underwater observation unit, an underwater vehicle, or an underwater processing station.

Abstract: An underwater wireless optical communication, UWOC, unit (30) for underwater deployment on a submerged earth layer (12) or structure (14, 16). The UWOC unit is configured for wireless optical communication in an underwater environment, and comprises an optical transmitter (36), an anidolic optical receiver (38), and a processor (44). The optical transmitter is configured to transmit data by emitting an optical signal (80) into the surroundings. The optical receiver includes an optical detector (62), which is omnidirectionally sensitive and configured to receive further optical signals approaching substantially along an azimuthal plane orthogonal to a nominal axis (A) through the UWOC unit. The processor is coupled to the optical receiver, and configured to process received further optical signals.

Abstract: An underwater wireless optical communication, UWOC, unit (30) for underwater deployment on a submerged earth layer (12) or structure (14, 16). The UWOC unit is configured for wireless optical communication in an underwater environment, and comprises an optical transmitter (36), an anidolic optical receiver (38), and a processor (44). The optical transmitter is configured to transmit data by emitting an optical signal (80) into the surroundings. The optical receiver includes an optical detector (62), which is omnidirectionally sensitive and configured to receive further optical signals approaching substantially along an azimuthal plane orthogonal to a nominal axis (A) through the UWOC unit. The processor is coupled to the optical receiver, and configured to process received further optical signals.

Abstract: A sensor circuit (10), including a silicon photomultiplier, SiPM, sensor (20), a voltage source (32), a current-to-voltage converter (24), and a limiting bias circuit (34). The SiPM sensor (20) has avalanche photodiode, APD, elements (30) connected in parallel between a cathode (K) and an anode (A). The voltage source (32) is configured to apply a reversed bias voltage (Vb) across the SiPM sensor, so that each APD element operates in reverse-biased Geiger mode, and the APD elements operate in integration mode. The bias circuit (34) is connected between the voltage source (32) and the anode, and is configured to limit currents through the APD elements, and to present an AC load impedance for an alternating current within a predetermined operating frequency range (fo) generated by the APD elements at the anode (A) as well as a DC load impedance, such that said AC load impedance is lower than said DC load impedance.

Abstract: A method and sensor system for monitoring in time a geometric property of a gasket (32, 34) that sealingly interconnects two structural members (20, 21) of a subterraneous or immersed tunnel (10). The system includes a sensor (42) for measuring position indications for surface portions (48) of the gasket relative to a reference (26, 27, 47) associated with one or both structural members, and a processor (44) that is coupled with the sensor to receive the position indications. The processor is configured to derive indications of displacement (?Y) for each of the gasket surface portions based on the measured indications of position, to compare the indications of displacement for each of the gasket surface portions with at least one threshold value (Ty), and to generate a warning message for an operator if at least one of the indications of displacement transgresses the at least one threshold value.

Abstract: An observation unit (30) for underwater deployment on/in a submerged earth layer (12) or structure. The unit comprises a housing (32), a light source (36), an underwater imaging device (40), a processor device (44), and a communication device (35). The housing supports the underwater observation unit relative to the submerged layer or structure. The light source is fixed to the housing, and configured to emit light into the unit's surroundings. The imaging device is attached to the housing, and configured to acquire image data of a second light source located within a FOV of the camera that covers the surroundings of the unit. The processor device is configured to determine positional data of the second light source relative to the imaging device, from the image data. The communication device is configured to transmit the positional data to another underwater observation unit, an underwater vehicle, or an underwater processing station.

Abstract: Apparatus for determining a spatial property in a 3D-space, wherein the apparatus comprises a physical pointer, a camera and a position and orientation measurement system, wherein a first object in the 3D-space comprises a pattern on it, wherein the physical pointer is configured to contact a surface area of a second object in the 3D-space, wherein the camera is configured to capture, at a position of the camera with respect to the first object, image data comprising an image of the pattern; wherein the position and orientation measurement system is configured to determine a heading, position, verticality, attitude, and/or inclination of the camera based on the image of the pattern, and determine, based on the determined heading, position, verticality, attitude, and/or inclination of the camera and a relative position of the physical pointer with respect to the camera, the spatial property of the surface area by the physical pointer.

Abstract: An underwater positioning system provides position information for a rover, moveable within a reference frame. The system may comprise: at least one beacon having a light source, located at a fixed position within the reference frame; an underwater imaging device, moveable with the rover in the reference frame to observe the light source from different viewpoints and determine direction data representing a direction or change in direction of the light source with respect to the imaging device; an orientation sensor, associated with the imaging device to determine an orientation of the imaging device with respect to the reference frame and generate orientation data; and a scaling element for providing scaling data representative of a distance between the imaging device and the light source. Various different beacons may be provided. In alternative system implementations, the locations of light source(s) and underwater imaging device are reversed between rover and beacon(s).

Abstract: An underwater positioning system provides position information for a rover, moveable within a reference frame. The system may comprise: at least one beacon having a light source, located at a fixed position within the reference frame; an underwater imaging device, moveable with the rover in the reference frame to observe the light source from different viewpoints and determine direction data representing a direction or change in direction of the light source with respect to the imaging device; an orientation sensor, associated with the imaging device to determine an orientation of the imaging device with respect to the reference frame and generate orientation data; and a scaling element for providing scaling data representative of a distance between the imaging device and the light source. Various different beacons may be provided. In alternative system implementations, the locations of light source(s) and underwater imaging device are reversed between rover and beacon(s).

Abstract: A device for monitoring a height profile of an ocean floor. The device comprises an elongated structure, and includes a first fluid conduit for accommodating a first liquid, at least one differential pressure transducer provided along the elongated structure, and in fluid communication with the first liquid at a first pressure based on the communicating vessels principle and with a second liquid at a second pressure, when in use. The at least one pressure transducer is configured for measuring differential pressures between the corresponding first and second pressures. The device further comprises a pressure compensator for exerting on the first liquid an inner reference pressure in response and proportional to an outer reference pressure exerted on the pressure compensator by the body of water at a reference position.