An optical distance measurement device includes: a photodetector including PDs for receiving interference light output from an optical interference unit and outputting detection signals of the interference light; and a switch for selecting one of the detection signals output from the PDs, in which a distance calculation unit calculates a distance to a measurement object on the basis of the detection signal selected by the switch.

A distance measuring system includes: a reference member configured to be provided on a surface of a first pipe made of metal, the reference member serving as a reference for distance measurement; an attachment member provided on a surface of a second pipe, made of metal, connected with the first pipe through a weld; a distance sensor configured to be attached to the attachment member, to measure a distance to the reference member; and a measuring unit configured to measure the distance based on an output from the distance sensor.

The invention relates to an apparatus for irradiating an object, in particular for light-curing a dental object by means of a first radiation, the apparatus comprising at least one radiation source for emitting the first radiation, the apparatus further comprising at least one radiation sensor for measuring at least a second radiation, and the apparatus further comprising a housing. The second radiation is the first radiation reelected by the object.

Described herein is a detector (110) for determining a position of at least one object (112). The detector (110) includes: at least one transfer device (114) with chromatic aberration; at least one aperture element (118), wherein the aperture element (118) is configured to block edge components of a light beam (120) propagating from the object (112) to the detector (110) and having passed the transfer device (114); at least one first optical sensor (126) positioned in a direction of propagation of the light beam (120) behind the aperture element (118); and at least one second optical sensor (128), wherein the second optical sensor (128) is configured to determine at least one second intensity information of the edge components of the light beam (120).

A method and system described for sensing a displacement by receiving and propagating a laser light signal with an etched waveguide that is configured to enable an evanescent optical field above the waveguide surface. A movable perturber can be positioned so the perturber interacts with the evanescent optical field above the waveguide surface. An optical phase shift can be induced in the waveguide when the movable perturber is displaced in the evanescent optical field, and the optical phase shift can be measured with an optical readout circuit.

A high-sensitivity optical system to determine and/or control spatial displacement and position of objects applicable to various situations when a contact measurement cannot be performed, such as in high-vacuum or ultra-high vacuum chambers, at high temperatures, in aggressive chemical environments, etc. A laser beam is directed at a low glancing angle to a screen secured to an object. The screen's surface is normal to a motion direction of interest. A location of the bright laser beam spot on the screen surface is acquired and the displacement thereof is analyzed and quantified based on the change in distance from the laser beam spot to a reference element which is arranged on the screen and creates a variation in the acquired image brightness. A feedback loop control mechanism is provided which returns the displaced object to its original position.

A portable truss structure experiment device, belonging to the field of teaching practice in structural mechanics of Civil Engineering. The device comprises a basic framework, detachable beams, locating rods, a slide rail, hinge supports, a truss structure, reflectors, measurement apparatuses and a collection apparatus. The device has the advantages of simple structure, convenient assembly and disassembly, reuse, accurate measurement result, can be synchronized to a large screen to directly obtain a structure influence line, and can implement classroom demonstration of the teaching content of an influence line in structure mechanics. Through experiments, students can understand relevant theories of the influence line in structural mechanics more accurately.

A distance measuring device includes a measuring member holding a length measuring instrument and at least one rail member (base member) on which the measuring member is movably disposed. When a straight line parallel to a direction in which the measuring member disposed on the base member moves is defined as a reference line, an angle formed by a straight line parallel to an axial length direction of a reaction tube and the reference line, which are on an identical plane, is constant for the plurality of reaction tubes disposed side by side along the reference line. A measurement direction of the length measuring instrument is parallel to the axial length direction of the reaction tube in a state where the measuring member is disposed on the base member. The measuring member is disposed on the base member to be able to sequentially move.

The present disclosure is directed to a system and method of controlling a facial recognition process by validating preconditions with a ranging sensor. The ranging sensor transmits a ranging signal that is reflected off of a user's face and received back at the ranging sensor. The received ranging signal can be used to determine distance between the user's face and the mobile device or to determine the reflectivity of the user's face. Comparing the distance to a range of distances corresponding to normal operation of the device or normal reflectivities associated with human skin tones can reduce the number of false positive activations of the facial recognition process. Furthermore, a multiple zone ranging sensor can produce a face depth map that can be compared to a stored face depth map or can produce a reflectivity map that can be compared to a stored face reflectivity map to further increase power efficiency and device security.

Systems and methods for optically measuring a position of a measurement surface relative to a reference position. The system is a wireless network comprising a centrally located data acquisition computer and a multiplicity of remotely located sensor modules mounted at different locations within wireless communication range of a central receiver. Each sensor module is mounted to a clamp that is made specific to a control surface location and embedded with an RFID tag to denote clamp location. The optical components of the sensor modules are selected to enable indication of the linear position of a measurement surface relative to a reference position and then broadcast the measurement results. The broadcast results are received by the central receiver and processed by the data acquisition computer, which hosts human interface software that displays measurement data.