Accurate photodetector measurements for lidar

Abstract

An optical ranging system may include a laser device and an imaging device with a light sensor. The laser device illuminates a scene with laser pulsed radiation that is reflected from objects in the scene. The reflection can vary greatly depending on the reflective surface shape and reflectivity. The signal measured by the light sensor can be filtered with several matched filters designed according to the curves of different reflected signals. The best matched filter can be identified and thus information about the reflective surface and accurate ranging information can be obtained. The laser pulsed radiation can be emitted in decoded pulses by allowing for weighting of different detection intervals. Other enhancements include interleaving the laser pulses and changing the operating state of the photodetectors of the pixel sensors, and efficient signal processing using a sensor chip that includes processing circuitry and light sensors.

Description

[0001] Cross References to Related Applications [0002] This application claims U.S. Provisional Application No. 62 / 465,310, filed March 1, 2017, entitled "System And Method Of Object Detection Using Coded Optical Pulses" priority to U.S. Provisional Application No. 62 / 596,002, filed December 7, 2017, entitled "Accurate Photo Detector Measurements For Lidar" and is a non-provisional application of the above case, which is hereby incorporated by reference in its entirety for all purposes. Background technique [0003] Light Detection And Ranging (LIDAR) systems are used for object detection and ranging, for example, for vehicles such as cars, trucks, boats and the like. LIDAR systems are also used in mobile applications (eg, for facial recognition), home entertainment (eg, capturing gesture capture for video game input), and augmented reality. A LIDAR system measures distance to an object by illuminating a landscape with pulses from a laser, and then measuring the time for a...

AI Technical Summary

Problems solved by technology

[0004] Can be difficult to provide robust range accuracy up to a few centimeters under all conditions, especially at the economic cost of LIDAR systems

Promising new detector technologies such as single photon avalanche diodes (SPADs) are attractive but have significant drawbacks when used to measure time-of-flight and other signal properties, especially over a wide range of environmental conditions Significant drawbacks in terms of distance and target due to their limited dynamic range

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