Cepton Technologies, Inc.

Dongyi Liao

Mark Armstrong McCord

Jun Pei

Jon Day Allen

Wei Wei

Yupeng Cui

Roger David Cullumber

Zukai Wang

Chao Gu

Liqun Han

Mark A Mccord

A LiDAR system includes a fixed frame, a first platform, an electro-optic assembly including one or more laser sources and one or more detectors mounted on the first platform; a flexure assembly flexibly coupling the first platform to the fixed frame; a drive mechanism configured to translate the first platform with respect to the fixed frame in two dimensions in a plane substantially perpendicular to an optical axis of the LiDAR system; and a controller configured to cause the drive mechanism to translate the first platform in a first direction with a first frequency and in a second direction orthogonal to the first direction with a second frequency that is different from the first frequency, acquire a point cloud, and output the point cloud at a frame rate that is an integer times a difference between the second frequency and the first frequency, the integer being greater than one.

Half and quarter lissajous scan patterns for LiDAR

A method of calibrating a LiDAR sensor mounted on a vehicle includes storing a reference three-dimensional image acquired by the LiDAR sensor while the LiDAR sensor is in an expected alignment with respect to the vehicle. The reference three-dimensional image includes a first image of a fixed feature on the vehicle. The method further includes, acquiring, using the LiDAR sensor, a three-dimensional image including a second image of the fixed feature, and determining a deviation from the expected alignment of the LiDAR sensor with respect to the vehicle by comparing the second image of the fixed feature in the three-dimensional image to the first image of the fixed feature in the reference three-dimensional image.

Dynamic calibration of lidar sensors

A LiDAR system includes one or more light sources configured to emit a set of light pulses in a temporal sequence with randomized temporal spacings between adjacent light pulses, one or more detectors configured to receive a set of return light pulses, and a processor configured to: determine a time of flight for each return light pulse of the set of return light pulses; and obtain a point cloud based on the times of flight of the set of return light pulses. Each point corresponds to a respective return light pulse. The processor is further configured to, for each respective point of the set of points in the point cloud: analyze spatial and temporal relationships between the respective point and a set of neighboring points in the set of points; and evaluate a quality factor for the respective point based on the spatial and temporal relationships.

Techniques for detecting cross-talk interferences in LiDAR imaging sensors with multiple light sources

A method of calibrating a LiDAR sensor mounted on a vehicle includes positioning the vehicle at a distance from a target including a planar mirror and features surrounding the mirror. The vehicle is positioned and oriented relative to the mirror so that an optical axis of the LiDAR sensor is nominally parallel to the optical axis of the mirror, and the target is nominally centered at a field of view of the LiDAR sensor. The method further includes acquiring, using the LiDAR sensor, a three-dimensional image of the target including images of the features of the target and a mirror image of the vehicle formed by the mirror. The method further includes determining a deviation from an expected alignment of the LiDAR sensor with respect to the vehicle by analyzing the images of the features and the mirror image of the vehicle in the three-dimensional image of the target.

Calibration of LiDAR sensors

Techniques for detecting cross-talk interferences in LiDAR imaging sensors

A method of three-dimensional imaging includes scanning a LiDAR system in a first direction with a first frequency and in a second direction with a second frequency that is different from the first frequency, so that a laser beam emitted by each laser source of the LiDAR system follows a Lissajous pattern. The method further includes emitting, using each laser source, a plurality of laser pulses as the LiDAR system is scanned in the first direction and the second direction; detecting, using each detector of the LiDAR system, a portion of each laser pulse of the plurality of laser pulses reflected off of one or more objects; determining, using a processor, a time of flight for each respective laser pulse from emission to detection; and acquiring a point cloud of the one or more objects based on the times of flight of the plurality of laser pulses.

Methods for scanning a LiDAR system in two dimensions

A lidar system includes a laser source, an emission lens configured to collimate and direct a laser beam emitted by the laser source, a receiving lens configured to receive and focus a return laser beam reflected off of one or more objects to a return beam spot at a focal plane of the receiving lens, and a detector including a plurality of photo sensors arranged as an array at the focal plane of the receiving lens. Each photo sensor has a respective sensing area and is configured to receive and detect a respective portion of the return laser beam. The lidar system further includes a processor configured to determine a respective time of flight for each respective portion of the return laser beam, and construct a three-dimensional image of the one or more objects based on the respective time of flight for each respective portion of the return laser beam.

Detector designs for improved resolution in lidar systems

A headlamp module of a vehicle includes a housing including a window, an illumination submodule disposed inside the housing and configured to provide illumination light to be transmitted through the window toward a scene in front of the vehicle, and a first LiDAR sensor disposed inside the housing and laterally displaced from the illumination submodule. The first LiDAR sensor includes one or more laser sources configured to emit laser beams to be transmitted through the window toward the scene, the laser beams being reflected off of one or more objects in the scene, thereby generating return laser beams to be transmitted through the window toward the first LiDAR sensor and one or more detectors configured to receive and detect the return laser beams.

Systems for incorporating LiDAR sensors in a headlamp module of a vehicle

An optical system includes a laser source having an emission area that has a first width in a first direction and a first height in a second direction orthogonal to the first direction, the first width being greater than the first height. The optical system further includes a cylindrical lens having a negative power and positioned in front of the laser source. The cylindrical lens is oriented such that a power axis of the cylindrical lens is along the first direction. The cylindrical lens is configured to transform the emission area of a laser beam emitted by the laser source into a virtual emission area having a virtual width and a virtual height, where the virtual width is less than the first width. The optical system further includes an rotationally symmetric lens positioned downstream from the cylindrical lens and configured to collimate and direct the laser beam towards a far-field.

Optical designs using cylindrical lenses for improved resolution in lidar systems

A light projection system includes a base, a lens, and a set of flexures flexibly attaching the lens to the base. The light projection system further includes a board fixedly attached to the base, and a light source mounted on the board and spaced apart from the lens along an optical axis of the lens. The light source is configured to emit a light beam to be projected by the lens toward a scene. The light projection system further includes a driving mechanism configured to scan the lens via the set of flexures in a plane substantially perpendicular to the optical axis of the lens, thereby scanning the light beam emitted by the light source over the scene.

Systems and methods for light projection

An imaging system includes a base, an imaging lens fixedly attached to the base, a board, a first set of flexures flexibly attaching the board to the base, and a detector mounted on the board and positioned at an image plane of the imaging lens. The imaging system further includes a driving mechanism configured to scan the board via the first set of flexures in a plane substantially perpendicular to an optical axis of the imaging lens, thereby scanning the detector to a plurality of image positions in the image plane. The imaging system further includes electronic circuitry configured to read out a respective electrical signal output by the detector as the detector is scanned to each respective image position of the plurality of image positions in the image plane, and generate an image based on the electrical signals read out from the detector at the plurality of image positions.

Systems and methods for imaging using mechanical scanning mechanisms

Techniques for detecting cross-talk interferences in lidar imaging sensors

A scanning lidar system includes a fixed frame, a first platform, and a first electro-optic assembly. The first electro-optic assembly includes a first laser source and a first photodetector mounted on the first platform. The scanning lidar system further includes a first flexure assembly flexibly coupling the first platform to the fixed frame, and a drive mechanism configured to scan the first platform with respect to the fixed frame in two dimensions in a plane substantially perpendicular to an optical axis of the lidar system. The scanning lidar system further includes a controller coupled to the drive mechanism. The controller is configured to cause the drive mechanism to scan the first platform in a first direction with a first frequency and in a second direction with a second frequency. The second frequency is similar but not identical to the first frequency.

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Mountain View, CA, United States of America

Dongyi Liao