TimeofFlightSysteme

TimeofFlightSysteme are optical sensors that measure distance by detecting the travel time of light between a source, a scene, and a detector. They are used to generate depth maps, 3D point clouds, or range images.

They operate in two main ways: direct time-of-flight (dToF), which measures the actual round-trip time of a short light pulse with fast time-to-digital converters; and indirect time-of-flight (iToF), which uses a continuous wave or modulated light and computes distance from the phase shift between emitted and returned light. In iToF, distance is proportional to the phase shift divided by modulation frequency, expressed as d = (c * Phase) / (4π f). dToF can offer high temporal resolution and short-range accuracy, while iToF is often easier to implement in compact devices for longer-range depth sensing.

Common components include an infrared emitter (LED or VCSEL), a detector (photodiode, SPAD), optics to shape the field of view, and processing electronics that compute phase or time measurements and convert them into depth data. Systems may include calibration routines to account for internal delays and channel offsets.

Applications span consumer devices such as smartphone depth sensing and augmented reality, robotics and automation for obstacle avoidance and mapping, automotive sensing, industrial metrology, and 3D scanning. ToF systems offer advantages such as compact form factors, real-time depth at reasonably high frame rates, and robustness to varying lighting compared to some structured-light methods. Challenges include multipath reflections, low reflectivity surfaces, ambient light interference, power consumption, and the need for precise calibration to achieve high accuracy.