Methods and systems for calibration of multiple lidar devices with non-overlapping fields of view

A non-transitory computer-readable storage medium that provides instructions, which when executed by a processor cause said processor to perform operations for calibration of a first lidar device and a second lidar device from a plurality of lidar devices that are mounted on a vehicle, the operations comprising:

• receiving lidar returns recorded by the first lidar device and the second lidar device as the vehicle moves along a path in an environment according to a predetermined path pattern;
• determining, based on a first subset of the lidar returns that are recorded by the first lidar device, positions of the vehicle along the path with respect to a world coordinate system;
• determining a subset of pairs of the positions of the vehicle, wherein each pair from the subset of pairs includes a first position and a second position of the vehicle, and wherein a first field of view of the first lidar device when the vehicle is located at the first position at a first time overlaps with a second field of view of the second lidar device when the vehicle is located at the second position at a second time;
• determining, for each pair from the subset of pairs of the positions, an estimate of transformation between the first subset of the lidar returns recorded by the first lidar device when the vehicle was located at the first position and a second subset of the lidar returns recorded by the second lidar device when the vehicle was located at the second position to produce a plurality of estimates of transformations for the pairs of the positions;
• and
• determining, based on the plurality of estimates of the transformations, an extrinsic calibration transformation that transforms a position of the second lidar device on the vehicle into a calibrated position of the second lidar device that allows to obtain a consistent view of the world between the first lidar device and the second lidar device.

A computing device for calibration of a first lidar device and a second lidar device from a plurality of lidar devices that are mounted on a vehicle, the computing device comprising:

• a non-transitory computer-readable storage medium to store instructions;
• and
• a processor coupled with the non-transitory computer readable storage medium to process the stored instructions to perform the following operations of:
• receiving lidar returns recorded by the first lidar device and the second lidar device as the vehicle moves along a path in an environment according to a predetermined path pattern,
• determining, based on a first subset of the lidar returns that are recorded by the first lidar device, positions of the vehicle along the path with respect to a world coordinate system,
• determining a subset of pairs of the positions of the vehicle, wherein each pair from the subset of pairs includes a first position and a second position of the vehicle, and wherein a first field of view of the first lidar device when the vehicle is located at the first position at a first time overlaps with a second field of view of the second lidar device when the vehicle is located at the second position at a second time,
• determining, for each pair from the subset of pairs of the positions, an estimate of transformation between the first subset of the lidar returns recorded by the first lidar device when the vehicle was located at the first position and a second subset of the lidar returns recorded by the second lidar device when the vehicle was located at the second position to produce a plurality of estimates of transformations for the pairs of the positions, and
• determining, based on the plurality of estimates of the transformations, an extrinsic calibration transformation that transforms a position of the second lidar device on the vehicle into a calibrated position of the second lidar device that allows to obtain a consistent view of the world between the first lidar device and the second lidar device.