Receiving system for lidar, lidar and method for inhibiting ghost lines
A receiving system for a lidar, comprises: a receiving lens, configured to receive echoes of a detection laser beam reflected by an object from an exterior of the lidar; a reflective structure, disposed downstream of an optical path of the receiving lens, to receive the echoes from the receiving lens, and change a propagation direction of the echoes by reflection; a detector, disposed downstream of an optical path of the reflective structure to receive a reflected echo from the reflective structure; and a ghost line reduction device, disposed between the reflective structure and the detector, wherein the ghost line reduction device includes a physical structure to block an echo that causes a ghost line in a point cloud of the lidar from entering the detector. The receiving system resolves the misrecognition problem caused by ghost lines in the point cloud to improve the detection accuracy of the lidar.
1 . A receiving system for a lidar, comprising:
a receiving lens, configured to receive echoes of a detection laser beam reflected by an object from an exterior of the lidar;
a reflective structure, disposed downstream of an optical path of the receiving lens, to receive the echoes from the receiving lens, and change a propagation direction of the echoes by reflection;
a detector, disposed downstream of an optical path of the reflective structure to receive a reflected echo from the reflective structure; and
a ghost line reduction device, disposed between the reflective structure and the detector, wherein the ghost line reduction device includes a physical structure to block an echo that causes a ghost line in a point cloud of the lidar from entering the detector,
wherein the ghost line reduction device comprises at least one of an aperture or one or more light barrier plates,
wherein the aperture and the detector satisfy the following relationship:
arctan
(
d
2
h
)
≤
arctan
(
D
2
f
)
D representing a diameter of the receiving lens, f representing a focal length of the receiving lens, h representing a distance between the aperture and the detector, and
d representing a width of the aperture,
wherein the detector and the one or more light barrier plates are disposed on a common circuit board, the one or more light barrier plates being located on one or both lateral sides of the detector on the common circuit board.
2 . The receiving system according to claim 1 , wherein the aperture comprises a slot-shaped aperture or a circular-shape aperture, and the aperture is made of one of following materials: metal, glass capable of absorbing or reflecting light, or ceramic.
3 . The receiving system according to claim 1 , wherein the reflective structure comprises a plurality of mirrors, and the ghost line reduction device is configured to block an echo other than an echo that is reflected once by the mirrors of the reflective structure.
4 . The receiving system according to claim 1 , wherein the reflective structure comprises a first mirror and a second mirror disposed opposite to each other, the detector comprises a photodiode, and the ghost line reduction device is configured to block an echo other than an echo that is reflected once by the first mirror and once by the second mirror.
5 . The receiving system according to claim 1 , wherein the ghost line reduction device comprises the aperture and the light barrier plate.
6 . A lidar, comprising:
an emitting system comprises a plurality of emitters to emit a detection laser beam; and
a receiving system, wherein the receiving system comprises:
a receiving lens, configured to receive echoes of the detection laser beam reflected by an object;
a reflective structure, disposed downstream of an optical path of the receiving lens, to receive the echoes from the receiving lens, and change a propagation direction of the echoes by reflection;
a detector, disposed downstream of an optical path of the reflective structure to receive a reflected echo from the reflective structure; and
a ghost line reduction device, disposed between the reflective structure and the detector, wherein the ghost line reduction device includes a physical structure to block an echo that causes a ghost line in a point cloud of the lidar from entering the detector,
wherein the ghost line reduction device comprises at least one of an aperture or one or more light barrier plates,
wherein the aperture and the detector satisfy the following relationship:
arctan
(
d
2
h
)
≤
arctan
(
D
2
f
)
D representing a diameter of the receiving lens, f representing a focal length of the receiving lens, h representing a distance between the aperture and the detector, and
d representing a width of the aperture,
wherein the detector and the one or more light barrier plates are disposed on a common circuit board, the one or more light barrier plates being located on one or both lateral sides of the detector on the common circuit board.
7 . The lidar according to claim 6 , wherein the aperture comprises a slot-shaped aperture or a circular-shape aperture, and the aperture is made of one of following materials: metal, glass capable of absorbing or reflecting light, or ceramic.
8 . The lidar according to claim 6 , wherein the reflective structure comprises a plurality of mirrors, and the ghost line reduction device is configured to block an echo other than an echo that is reflected once by the mirrors of the reflective structure.
9 . The lidar according to claim 6 , wherein the reflective structure comprises a first mirror and a second mirror disposed opposite to each other, the detector comprises a photodiode, and the ghost line reduction device is configured to block an echo other than an echo that is reflected once by the first mirror and once by the second mirror.
10 . The lidar according to claim 6 , wherein the ghost line reduction device comprises the aperture and the light barrier plate.
11 . A method for suppressing ghost lines for a lidar, comprising:
receiving, through a receiving lens, echoes of a detection laser beam reflected by an object from an exterior of the lidar;
receiving, through a reflective structure, the echoes from the receiving lens, and changing a propagation direction of the echoes by reflection;
blocking, by a ghost line reduction device, an echo that causes a ghost line in a point cloud of the lidar; and
receiving an unblocked echo from the reflective structure through a detector,
wherein the ghost line reduction device comprises at least one of an aperture or one or more light barrier plates,
wherein the aperture and the detector satisfy the following relationship:
arctan
(
d
2
h
)
≤
arctan
(
D
2
f
)
D representing a diameter of the receiving lens, f representing a focal length of the receiving lens, h representing a distance between the aperture and the detector, and
d representing a width of the aperture,
wherein the detector and the one or more light barrier plates are disposed on a common circuit board, the one or more light barrier plates being located on one or both lateral sides of the detector on the common circuit board.