L515 ToF working principle
I'm doing some experiments with the L515 and I needed to know which ToF working principle it uses. Since the return light is collected by a single avalanche photodiode (APD), can I assume that it is a direct ToF technique? That is, instead of a continuous sinusoidal light wave, does it works only with a single pulse?
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The L515 Camera uses LiDAR technology to measure the distance from the camera to the object. Similar to other LiDAR systems, the L515 sends a laser beam and measures the returned time of the reflected light off an object. The L515 accomplishes this using a continuous coded IR beam. The time taken for the light to return to the camera is used to calculate the distance of the object.
For more detail please visit Optimizing the Intel RealSense LiDAR Camera L515 Range.
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Thanks for the reply.
I know that L515 is a Lidar and that uses the difference between the emitted and returned light to measure distance. What I really want to know is how the laser beam is codded and the expression used to estimate depth. I know that ToF distance measurement can be based on single-pulse modulation or harmonic modulation (measurement of phase delay Φ). Since the IR beam is continuous I must assume that the measurement is based on continuous harmonic modulation? In that case, can I assume that distance is estimated by D = (c. τ)/2, where c is the speed of light and τ is Φ/(2.π.f)?
Yes, the formula for depth is D = c.ΔΦ/(4.π.f). You can refer to the Introduction to Intel RealSense LiDAR Camera L515 video (minutes 11 to 15) for the explanation of the L515 working principle.
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