US-20260126532-A1 - MULTI-DETECTOR LIDAR SYSTEMS AND METHODS FOR MITIGATING RANGE ALIASING

US20260126532A1US 20260126532 A1US20260126532 A1US 20260126532A1US-20260126532-A1

Abstract

A method including emitting, by a light emitter, a first light pulse into an environment at a first time, activating a plurality of light detectors including a first light detector and a second light detector, the first light detector and the second light detector having different fields of view, generating, by the plurality of a light detectors, a plurality of analog signals based on return light reflected from the environment, converting, by a circuit configuration coupled to the plurality of light detectors, the plurality of analog signal to digital data, determining, based on the digital data, distance information associated with one or more objects in the environment.

Inventors

Dane P. Bennington
Ryan T. Davis
Michel H.J. Laverne

Assignees

LG INNOTEK CO., LTD.

Dates

Publication Date: 20260507
Application Date: 20251218

Claims (20)

1 . A method comprising: emitting, by a light emitter, a first light pulse into an environment at a first time; activating a plurality of light detectors including a first light detector and a second light detector, the first light detector and the second light detector having different fields of view, generating, by the plurality of a light detectors, a plurality of analog signals based on return light reflected from the environment; converting, by a circuit configuration coupled to the plurality of light detectors, the plurality of analog signal to digital data; determining, based on the digital data, distance information associated with one or more objects in the environment.
2 . The method of claim 1 , wherein the circuit configuration comprises a summing circuit, and wherein converting the plurality of analog signals further comprises: combining, by summing circuit, the plurality of analog signals into a combined analog signal; and converting, by a single analog-to-digital converter (ADC), the combined analog signal into the digital data.
3 . The method of claim 2 , wherein the circuit configuration further comprises one or more attenuators, and wherein the method further comprising: attenuating, by the one or more attenuators, at least one analog signal of the plurality of analog signals prior to combining the plurality of analog signals into the combined analog signal.
4 . The method of claim 3 , wherein the attenuating the at least one analog signal comprises: selectively attenuating an output of the first light detector or the second light detector based on an expected time of arrival of the return light corresponding to the first light pulse.
5 . The method of claim 1 , wherein the circuit configuration comprises a plurality of ADC, and wherein converting the plurality of analog signals comprises: converting, by a first ADC of the plurality of ADC, a first analog signal form the first light detector; and converting, by a second ADC of the plurality of ADC, a second analog signal from the second light detector.
6 . The method of claim 1 , wherein the field of view of the first light detector corresponds to a first range from the light emitter, and the field of view of the second light detector corresponds to a second range from the light emitter, the first range being closer to the light emitter than second range.
7 . The method of claim 1 , further comprising: emitting, by the light emitter, a second light pulse into the environment at a second time; and determining, based on the digital data indicating detection of the return light by second light detector, that the return light is associated with the first light pulse while the second light pulse is traversing the environment.
8 . A non-transitory computer readable medium including computer-executable instructions stored thereon, which when executed by one or more processors, cause the one or more processors to perform operations of: causing to emit, by a light emitter, a first light pulse into an environment at a first time; activating a plurality of light detectors including a first light detector and a second light detector, the first light detector and the second light detector having different fields of view, generating, by the plurality of a light detectors, a plurality of analog signals based on return light reflected from the environment; converting, by a circuit configuration coupled to the plurality of light detectors, the plurality of analog signal to digital data; determining, based on the digital data, distance information associated with one or more objects in the environment.
9 . The non-transitory computer readable medium of claim 8 , wherein the circuit configuration comprises a summing circuit configured to combine the plurality of analog signals into a single output, and a single ADC configured to convert the single output into the digital data.
10 . The non-transitory computer readable medium of claim 9 , wherein the instructions further cause the one or more processors to perform operations of: causing one or more attenuators coupled to the plurality of light detectors to selectively attenuate an output of the first light detector or the second light detector.
11 . The non-transitory computer readable medium of claim 10 , wherein causing the one or more attenuators to selectively attenuate comprises: determining a time interval during which return light associated with the first light pulse is expected to be within the field of view of the first light detector; causing an attenuator associated with the second light detector to attenuate the output of the second light detector during the determined time interval.
12 . The non-transitory computer readable medium of claim 8 , wherein the circuit configuration comprises a plurality of ADC, each ADC respectively associated with one of the plurality of light detectors.
13 . The non-transitory computer readable medium of claim 8 , wherein activating the plurality of light detectors comprises providing a bias voltage to the plurality of light detectors, wherein the bias voltage varies over time according to a predetermined function.
14 . A system comprising: a light emitter configured to emit a light pulse; a plurality of light detectors including a first light detector and a second light detector configured to generate analog signals in response to receiving return light, wherein the first light detector and the second light detector have different fields of view; a circuit configuration coupled to the plurality of light detectors and configured to convert the analog signals into digital data; and processor configured to determine range information based on the digital data.
15 . The system of claim 14 , wherein the circuit configuration comprises: a summing circuit configured to sum the analog signals from the plurality of light detectors into a combined signal; and a ADC configured to receive the combined signal and output the digital data to the processor.
16 . The system of claim 15 , wherein the circuit configuration further comprises: A plurality of attenuators, each attenuator disposed between each light detector of the plurality of light detectors and the summing circuit.
17 . The system of claim 16 , wherein the processor is further configured to control the plurality of attenuators to attenuate signals from detectors that are not expected to receive the return light during a specific time period.
18 . The system of claim 14 , wherein the circuit configuration comprises separate ADC for each of the plurality of light detectors.
19 . The system of claim 14 , wherein the plurality of light detectors are Avalanche Photodiodes (APDs), and the processor is configured to control activation of the APDs by adjusting a bias voltage provided to the APDs.
20 . The system of claim 14 , further comprising an actuation mechanism configured to dynamically adjust a direction of the different fields of view of the first light detector or the second light detector.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a Continuation of application Ser. No. 18/485,885, filed on Oct. 12, 2023, which is a continuation of U.S. application Ser. No. 17/070,765, filed on Oct. 14, 2020 (now U.S. Pat. No. 11,822,018 issued on Nov. 21, 2023), the entire contents of all these applications being hereby expressly incorporated by reference into the present application. BACKGROUND In some LIDAR systems (for example, bistatic LIDAR systems that use a single receiver to detect light emitted by a single emitter), the emitter used to emit light into the environment and the receiver used to detect return light reflecting from objects in the environment are physically displaced relative to each other. Such LIDAR configurations may inherently be associated with parallax problems because the light emitted by the emitter and received by the detector may not travel along parallel paths. For example, for a LIDAR system designed to operate at very short distances (for example, at a distance of 0.1 meters), the emitter and receiver may need to be physically tilted towards each other (as opposed to aligning them at infinity distance). However, this physical tilting may result in a loss of detection capabilities at long ranges from the LIDAR system. To address this, and to have the capability to handle both short and long-range detections, some LIDAR systems may use a combination of a wide field of view and the aforementioned tilted assembly. This wide field of view, however, may result in another set of problems, including increasing the amount of background light detected by the receiver without increasing the amount of light emitted by the emitter, which may significantly increase the signal to noise ratio of the receiver. Additionally, the use of the single receiver for the emitter (or even an array of receivers pointed in a common direction) can lead to other problems as well, such as difficulties in addressing range aliasing and cross-talk concerns. Range aliasing may arise when multiple light pulses are emitted by an emitter and are traversing the environment at the same time. When this is the case, the LIDAR system may have difficulty ascertaining which emitted light pulse the detected return light originated from. To provide an example, the emitter emits a first light pulse at a first time and then emits a second light pulse at a second time before return light from the first light pulse is detected by the receiver. Thus, both the first light pulse and the second light pulse are traversing the environment simultaneously. Subsequently, the receiver may detect a return light pulse a short amount of time after the second light pulse is emitted. However, the LIDAR system may have difficulty determining whether the return light is indicative of a short range reflection based on the second light pulse or a long range reflection based on the first light pulse. Cross-talk concerns may arise based on a similar scenario, but instead of detecting return light from a first light pulse emitted by the same emitter, the receiver from the LIDAR system may instead detect a second light pulse that originates from an emitter of another LIDAR system. In this scenario, the LIDAR system may mistake the detected second light pulse from the other LIDAR system as return light originating from the first light pulse. Similar to range aliasing, this may cause the LIDAR system to mistakenly believe that a short range object is reflecting light back towards the LIDAR system. BRIEF DESCRIPTION OF THE DRAWINGS The detailed description is set forth with reference to the accompanying drawings. The drawings are provided for purposes of illustration only and merely depict example embodiments of the disclosure. The drawings are provided to facilitate understanding of the disclosure and shall not be deemed to limit the breadth, scope, or applicability of the disclosure. In the drawings, the left-most digit(s) of a reference numeral may identify the drawing in which the reference numeral first appears. The use of the same reference numerals indicates similar, but not necessarily the same or identical components. However, different reference numerals may be used to identify similar components as well. Various embodiments may utilize elements or components other than those illustrated in the drawings, and some elements and/or components may not be present in various embodiments. The use of singular terminology to describe a component or element may, depending on the context, encompass a plural number of such components or elements and vice versa. FIG. 1 depicts an example system, in accordance with one or more example embodiments of the disclosure. FIGS. 2A and 2B depict an example use case, in accordance with one or more example embodiments of the disclosure. FIG. 3 depicts an example use case, in accordance with one or more example embodiments of the disclosure. FIGS. 4A and 4B depict example circuit configurations, in a