From fundamental physics to advanced 3D depth sensing applications. Your ultimate resource for mastering LiDAR, dToF vs iToF, and precision ranging solutions.
Introduction – From Daily Life to Core Technology Have you ever wondered how your iPhone unlocks with Face ID, or how a robot vacuum knows there’s a wall in front of it? Behind these everyday smart experiences is a powerful depth-sensing technology called Time-of-Flight (ToF). What Is a Time-of-Flight (ToF) Sensor? A Time-of-Flight (ToF) sensor is a distance-mapping technology that measures the time it takes for a light signal (usually infrared) to travel to an object and return to the sensor. Based on the speed of light, it calculates the precise distance and depth, creating a 3D map of the environment. A typical ToF system includes an emitter (sends light) and a receiver (detects reflected light). How Does a ToF Sensor Work? The Basic Principle Just like bats use echolocation, a ToF sensor sends out light, waits for it to bounce back, and calculates distance from the time delay. Distance = (Speed of Light × Time) / 2 How a ToF sensor emits IR light and measures depth. Types of ToF Sensors: dToF vs iToF Direct ToF (dToF) dToF measures the exact time delay of each light pulse. It offers high accuracy and long range, ideal for LiDAR and automotive systems. Indirect ToF (iToF) iToF measures the phase shift between emitted and received light waves. It’s compact and perfect for smartphones and indoor robotics. ToF vs Stereo Vision vs Structured Light Feature ToF Stereo Vision Structured Light Low Light Excellent Poor Good Range Medium–Long Short–Medium Short Where Are ToF Sensors Used? Smartphones: Face ID, AR, Bokeh Robotics & Drones: Obstacle avoidance, SLAM Automotive: Driver monitoring, gesture control View Our ToF Modules for Robotics → Frequently Asked Questions Does a ToF sensor work in the dark? Yes. It uses active infrared light. Is ToF the same as LiDAR? No. ToF is the principle; LiDAR is a specific implementation. What is the range of a ToF sensor? From centimeters to several meters, depending on design.
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