Methods and apparatus for object detection and identification in a multiple detector lidar array

• US 10,585,175 B2
• Filed: 06/06/2016
• Issued: 03/10/2020
• Est. Priority Date: 04/11/2014
• Status: Active Grant

• Current Assignee: Big Sky Financial Corporation
• Original Assignee: Big Sky Financial Corporation
• Inventors: Retterath, James E., Laumeyer, Robert A.
• Primary Examiner(s): Ratcliffe, Luke D
• Application Number:
  US15/173,969
• Publication Number:
  US 20160356881A1
• Time in Patent Office: 1,373 Days
• Field of Search: 356 301- 515, 356 401- 41, 356 501- 515, 356 6- 22, 356 28, 356 285
• CPC Class Codes: G01S 17/10 using transmission of interrupted, pulse-modulated waves determination of distance by phase measurements G01S17/32
• CPC Class Codes: G01S 17/26 wherein the transmitted pulses use a frequency-modulated or phase-modulated carrier wave, e.g. for pulse compression of received signals
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 17/931 of land vehicles
• CPC Class Codes: G01S 7/481 Constructional features, e.g. arrangements of optical elements
• CPC Class Codes: G01S 7/4815 using multiple transmitters
• CPC Class Codes: G01S 7/4817 relating to scanning
• CPC Class Codes: G01S 7/4863 Detector arrays, e.g. charge-transfer gates
• CPC Class Codes: G01S 7/4865 Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak peak detection in noise, signal conditioning G01S7/487
• CPC Class Codes: G01S 7/497 Means for monitoring or calibrating

Abstract

LiDAR (light detection and ranging) systems use one or more emitters and a detector array to cover a given field of view where the emitters each emit a single pulse or a multi-pulse packet of light that is sampled by the detector array. On each emitter cycle the detector array will sample the incoming signal intensity at the pre-determined sampling frequency that generates two or more samples per emitted light packet to allow for volumetric analysis of the retroreflected signal portion of each emitted light packet as reflected by one or more objects in the field of view and then received by each detector.

Claims

1. A LiDAR (light detection and ranging) system comprising:

an emitter that emits a series of multiple emitted light packets over a field of view that is in motion relative to the emitter, each emitted light packet emitted for a cycle duration and including a plurality of light pulses;

a detector array having an array of detectors configured to cover the field of view and sample an incoming retroreflected signal portion of an emitted light packet at a pre-determined sampling frequency that generates at least two samples corresponding to the cycle duration of the emitted light packet that are stored in a frame buffer;

a processing system configured to analyze the samples from the detector array and detect any objects within the field of view using at least a volumetric analysis of the at least two samples from each detector in the array of detectors corresponding to the incoming retroreflected signal portion of each emitted light packet, the volumetric analysis including an analysis of the frame buffer that is performed for multiple samples within that frame buffer such that there are multiple periodic samples that are evaluated to reconstruct and analyze the reflected light energy based on a multi-bit intensity value for each detector in the detector array for a given cycle.

2. The LiDAR system of claim 1 wherein the emitter is configured for in situ calibration by emitting pre-determined calibration patterns of emitted light energy and measuring an intensity, a location and an angle of the reflected portion of the emitted light energy.

3. The LiDAR system of claim 1 wherein the emitter emits light energy as coherent electromagnetic laser energy.

4. The LiDAR system of claim 1 wherein the LiDAR system is carried by a vehicle, the field of view is a road scene captured from the vehicle, and the LiDAR system is utilized by an autonomous vehicle navigation system.

5. A LiDAR (light detection and ranging) system comprising:

an emitter that emits a series of multiple emitted light packets over a field of view that is in motion relative to the emitter, each emitted light packet emitted for a cycle duration and including a plurality of light pulses;

a detector array having an array of detectors configured to cover the field of view and sample an incoming retroreflected signal portion of an emitted light packet at a pre-determined sampling frequency that generates at least two samples corresponding to the cycle duration of the emitted light packet;

a processing system configured to analyze the samples from the detector array and detect any objects within the field of view using at least a volumetric analysis of the at least two samples from each detector in the array of detectors corresponding to the incoming retroreflected signal portion of each emitted light packet,

wherein the emitter generates an emitted beam that is characterized to determine an intensity of the emitted beam throughout an entire cross section of the emitted beam and wherein the processing system utilizes the intensity of the emitted beam to differentiate light energy patterns and resolve between emitted and reflected light energy patterns.

6. A LiDAR (light detection and ranging) system comprising:

an emitter that emits a series of multiple emitted light packets over a field of view that is in motion relative to the emitter, each emitted light packet emitted for a cycle duration;

a detector array having an array of detectors configured to cover the field of view and sample an incoming retroreflected signal portion of an emitted light packet at a pre-determined sampling frequency that generates at least two samples corresponding to the cycle duration of the emitted light packet that are stored in a frame buffer, wherein each detector in the detector array has a unique angle through which the retroreflected signal portion of each emitted light packet is received;

a processing system configured to analyze the samples from the detector array and detect any objects within the field of view using at least a volumetric analysis of the at least two samples from each detector in the array of detectors corresponding to the incoming retroreflected signal portion of each emitted light packet, the volumetric analysis including an analysis of the frame buffer that is performed for multiple samples within that frame buffer such that there are multiple periodic samples that are evaluated to reconstruct and analyze the reflected light energy based on a multi-bit intensity value for each detector in the detector array for a given cycle.

7. The LiDAR system of claim 6 wherein the LiDAR system is carried by a vehicle, the field of view is a road scene captured from the vehicle, and the LiDAR system is utilized by an autonomous vehicle navigation system.