Abstract: A laser based range finder which may be inexpensively produced yet provides highly accurate precision range measurements has a number of user selectable target acquisition and enhanced precision measurement modes which may viewed on an in-sight display during aiming and operation of the instrument. Extremely efficient self-calibrating precision timing and automatic noise threshold circuits incorporated in the design provide a compact, low-cost, highly accurate and reliable ranging instrument for a multitude of uses and is adaptable for both recreational and laser based "tape measure" applications.

Abstract: A laser range finder including a receiver for detecting a return pulse and providing an output signal indicative thereof, a single integrated circuit digital range counter chip connected to receive the output signal from the receiver, a power supply unit for powering the receiver and range counter chip, and a single-chip microcontroller for selectively sequencing application of power to the receiver and to the range counter chip, for controlling laser firing, and for automatically recalibrating the receiver.

Abstract: A distance measuring equipment which is useful in, for example, a collision prevention system wherein a laser beam is forward emitted from a vehicle to measure a distance between the vehicle and a forward vehicle, and an alarm is produced when the present vehicle abnormally approaches the forward vehicle. In the distance measuring equipment, when a correction instruction signal is supplied, a distance calculating circuit first drives an optically shielded light emitting element for correction to emit light, and produces a correction signal on the basis of a signal input into an adder connected to a light receiving element. Thereafter, the distance calculating circuit drives a light emitting element for measurement to emit light, and produces a distance measurement signal with referring the correction signal.

Abstract: Optical distance measurement apparatus and method. The apparatus comprises a light emitting circuit, a light receiving circuit, a trigger signal generation circuit, a pollution sensor, a diode abnormal state sensor, a control/time-distance conversion circuit, a cleaning device and a car collision prevention device. The pollution sensor receives a part of a light beam which is emitted from the light emitting circuit and then reflected from protecting glass mounted on a front side of the apparatus, to sense a variation in a reflectivity of the protecting glass, and discriminates a polluted state of the protecting glass in accordance with the sensed result.

Abstract: In a light-wave distance meter based on light pulses, a light pulse radiation device radiates light pulses emitted by a light source device to a target of measurement, a light reception device receives reflected light pulses from the target, a sampling device samples reception signals, a timing device applies a dither of a certain range to the light pulse emission timing and sampling timing, a cumulative memory device stores sampled signals at a certain interval cumulatively, and a computation device calculates the distance to the target. The distance meter is capable of measuring the position of received light pulses at a resolution higher than the sampling timing.

Abstract: An automatic noise threshold circuit and method automatically sets an operating threshold for a signal receiving section of a laser pulse transmitting device such that a constant noise pulse firing rate is output from a detector to provide maximum return signal sensitivity and enable detection of the weakest possible laser pulse in order to obtain maximum performance out of a laser range finder. The circuit sets the noise pulse rate at that point at which, in conjunction with a firmware based process, the actual return signals from the target can be discrimintated from the accompanying noise.

Abstract: A highly precise range measurement instrument is made possible through the use of a novel and efficient precision timing circuit which makes use of the instrument's internal central processing unit crystal oscillator. A multi-point calibration function includes the determination of a "zero" value and a "cal" value through the addition of a known calibrated pulse width thereby providing the origin and scale for determining distance with the constant linear discharge of capacitor.

Abstract: Disclosed is a distance measuring equipment comprising: a light emitting element for generating a pulse beam; and a light receiving element for receiving a reflected pulse beam from an object under measurement with respect to the pulse beam generated from the light emitting element and converting the reflected pulse beam into an electric light receiving signal.

Abstract: Disclosed is a distance measuring apparatus having a clock generating element, a light emitting element, a light receiving element, a sample pulse generating element, a sample hold element and a processing element. The clock generating element generates a clock pulse at a predetermined time interval. The light emitting element generates a pulse beam in synchronism with the clock pulse. The light receiving element receives a reflected pulse beam from an object and converts it into an electric signal. The sample pulse generating element generates a sample pulse at a timing delayed by a predetermined minute time from a generating time of the clock pulse within one measuring period. The sample hold element effects sampling of an output signal from the light receiving element with the sample pulse. The processing element calculates a distance to the object by detecting it from the output signal of the sample hold element and from the delay time of the sample pulse.

Abstract: A method for determining the visual range improves the visual range measurement adopted as a basis, to the end that the measurement of the visual range can take place using one emitter and using one receiver, which are disposed to be stationary. The method permits the determination of the visual range, even though an obstacle is situated within the field of view. A comparison of a measured backscatter signal with a specimen curve permits the determination of the visual range from the intensity curve obtained, without any need, for this purpose, of further information such as, for example, the direction from which the backscatter signal comes.