A light beam is projected on a reference plane and an object to-be-measured, a phase difference between reflected lights from them is changed by a phase shifter, a drive voltage for causing the change of the phase difference is applied to the phase shifter, a magnitude of phase shift of the phase of the reflected lights is detected by a phase shift detector on the basis of the drive voltage at a point of time at which the change of the phase difference of the reflected lights has been compensate...

A submerged object indication system is carried from an aircraft flying above the water. A laser pulse generator directs a pulse at a small water area which may be 25 feet in diameter, and the receiver receives the air-water interface reflection which gates open a channel for receiving a submerged object reflection. A time delay is connected between an optical shutter and the detection circuit which receives the air-to-water interface reflection with the time delay related to the depth at which ...

A lidar with a laser transmitter for transmitting a laser beam and a receiver having receiving optics for detecting radiation reflected back from the beam by aerosol particles in the atmosphere, the receiver having an optical axis aligned with the beam. The receiver includes a number of radiation receiving elements such as concentric radiation detector elements placed in the receiving optics focal plane so that these concentric detector elements can measure backscatter radiation from the beam at...

In a laser beam X-Y scanning system for use, as for example, in turbid media such as sea water; the laser light reflected from objects is received by an image receiving device or detector such as a photomultiplier tube (PMT). The intensity level of the reflected light is maintained at an intensity level within the dynamic range of the image receiving device by controlling the effective intensity of the laser beam by varying the density of a plurality of series positioned variable neutral density...

The sensor includes a range finder having means for emitting a directional output of pulsed energy toward a fixed area, and includes a transmitter section which divides pulsed energy into divergent beams, which are then received as reflective energy in a receiver section. The receiver alternately selects between outputs of two detectors receiving reflections from the beam and provide inputs for purposes of determining time of flight, and for measuring the time interval between interceptions of t...

An optical method and optical device for distance measurement, comprising the steps of emitting an incident light beam (13) comprising at least two waves of differing wavelengths (.lambda.1 and .lambda.2); separating this beam into a reference beam (15) and a measurement beam (17) which are reflected on, respectively, a reference reflector (16) and a zone (18) of a part (19), of which it is desired to measure the position in the direction of the measurement beam and recombine into a resultant be...

A height sensor comprises a pair of light-emitting elements disposed at positions spaced at different distances from a surface desired to be measured, the elements alternately emitting light rays, and a light-receiving element for receiving a light ray generated from each light-emitting element and reflected by the measured surface, the element producing a signal corresponding to the quantity of light received. The signal outputted from the light-receiving element is logarithmically converted by...

A distance measuring apparatus installed on a car for measuring the distance of the car from the one in front. The distance measuring apparatus comprises a laser generator for emitting a laser beam, a photosensor for receipt of the laser beam reflected from the car in front, means for calculating the distance between the cars when the photosensor receives the reflected laser beam, and a control unit for controlling an adjustable range of the emitted laser beam according to the calculated distanc...

An active distance measuring apparatus comprises a projector for projecting modulated light to an object, a photo-sensor for sensing the modulated light reflected by the object to produce a pair of alternating current signals in accordance with a distance to the object, and a signal processor for producing a distance signal in accordance with the pair of alternating current signals. The signal processor includes a detector means for detecting a voltage corresponding to each of the pair of altern...

A distance measuring device comprises a light emitter, a light receiver including a plurality of photo-responsive elements for sensing the pulsating light beam emitted by the light emitter and subsequently reflected from a target object relative to which the distance from the device is to be measured, and a signal processing circuit. The signal processing circuit includes a logic circuit so designed as to determine the applicability of an output signal from one of light measuring circuits connec...