Definition
Time-of-flight is a method of measuring distance by timing how long a pulse of light takes to travel to an object and back. Since the speed of light is known, that travel time reveals exactly how far away the object is.
This principle underpins many laser scanners and depth sensors, letting them measure distances quickly and accurately. It is one of the core ways that 3D capture devices sense the world around them.
In simple terms, time-of-flight measures distance by clocking how long light takes to bounce back.
How It Works
A time-of-flight sensor sends out a pulse or wave of light toward a surface and detects the light that returns. By precisely measuring the delay between sending and receiving, it calculates the distance to that surface, since light travels at a constant, known speed.
Doing this across many directions produces distance measurements all around the sensor, which combine into a 3D point cloud. Time-of-flight is well suited to longer ranges, making it common in terrestrial and airborne laser scanning.
Applications
Time-of-flight is used in laser scanning, LiDAR, depth cameras, and robotics. It enables 3D capture of buildings and landscapes, supports autonomous navigation, and powers depth-sensing devices, serving as a foundational technique in reality capture.
Benefits
- Accurate distance measurement.
- Effective over longer ranges.
- Fast capture of many points.
- A basis for 3D scanning and LiDAR.
- Works in low-light conditions.
Related Terms
- LiDAR (Light Detection and Ranging)
- Terrestrial Laser Scanning (TLS)
- Point Cloud
- Laser Scanning
Frequently Asked Questions
How does time-of-flight measure distance?
It times how long a light pulse takes to travel to a surface and back, then uses the known speed of light to calculate the distance.
What is time-of-flight used for?
It is used in laser scanning, LiDAR, depth cameras, and robotics to measure distance and capture 3D data.
How does time-of-flight compare to phase-based scanning?
Time-of-flight suits longer ranges by timing pulses, while phase-based methods can be very precise at shorter ranges by analysing light waves.
Does time-of-flight work in the dark?
Yes, because it uses its own emitted light, it can operate in low-light conditions.
About Track3D
Track3D helps teams turn laser scan and LiDAR data into accurate digital twins. Learn more at Track3D.
