Laser rangefinder

An instrument that measures distance to a target using laser light, typically by timing the returned pulse or measuring a phase shift.

Time-of-flight camera: An imaging device that estimates distance from the travel time of emitted light. It uses the same round-trip timing principle, but measures many scene points at once.
Laser: A device that emits light through optical amplification based on stimulated emission. Laser rangefinders rely on its narrow, directional beam to illuminate a target.
LiDAR: A remote-sensing method that measures distance using reflected laser light. Laser rangefinding is the core measurement operation used in many LiDAR systems.
Ultrasonic rangefinder: An instrument that estimates distance from the travel time of reflected sound waves. It uses acoustic echoes rather than light, often at shorter ranges and lower precision.
Phase-shift measurement: A method that infers distance from the phase difference between transmitted and returned periodic signals. Continuous-wave rangefinders use phase shifts instead of timing isolated pulses.
Optical telescope: An instrument that collects and focuses light from distant objects. Rangefinder optics collect weak returns and direct them onto a detector.
Electronic distance measurement: The measurement of distance using electromagnetic waves and electronic instrumentation. Laser rangefinders are optical instruments within this broader measurement practice.
Radar: A system that detects objects and measures their distance or motion using radio waves. Radar ranges with radio-frequency echoes, which behave differently from optical returns.
Amplitude-modulated continuous-wave radar: A ranging method that derives distance from the frequency difference between transmitted and returned frequency-swept signals. It measures delay through beat frequency rather than direct optical pulse timing.
Signal-to-noise ratio: The ratio of a signal’s power to the power of background noise. A stronger return relative to ambient light improves the reliability of distance estimates.

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