US 12,412,401 B2
Traffic sign recognition device and traffic sign recognition method
Kazuhiro Miyazato, Susono (JP); and Toshiya Koyasu, Tokyo (JP)
Assigned to TOYOTA JIDOSHA KABUSHIKI KAISHA, Aichi-ken (JP); and DENSO CORPORATION, Aichi-pref (JP)
Filed by TOYOTA JIDOSHA KABUSHIKI KAISHA, Aichi-ken (JP); and DENSO CORPORATION, Aichi-pref (JP)
Filed on Jan. 23, 2023, as Appl. No. 18/157,843.
Claims priority of application No. 2022-009668 (JP), filed on Jan. 25, 2022.
Prior Publication US 2023/0237812 A1, Jul. 27, 2023
Int. Cl. G06T 7/70 (2017.01); G06V 20/58 (2022.01)
CPC G06V 20/582 (2022.01) [G06T 7/70 (2017.01); G06T 2207/10028 (2013.01)] 6 Claims
OG exemplary drawing
 
1. A traffic sign recognition device, comprising:
a storage device configured to store a camera image captured from a movable body and pieces of three-dimensional point group data; and
a processor configured to:
in a case where the camera image includes an image of a traffic sign candidate, estimate a relative position of the traffic sign candidate to the movable body based on the camera image;
specify a set of pieces of three-dimensional point group data including a relative position to the movable body among the pieces of three-dimensional point group data, the relative position of the specified set of pieces of three-dimensional point group data being equal to the relative position of the traffic sign candidate;
specify, in the camera image, an image region of an object including the traffic sign candidate, the image region of the object corresponding to a set region indicative of a region where the set is specified;
calculate, based on a size of the image region of the object and color components constituting the image of the object, a percentage of a predetermined color component constituting a guide sign among the color components constituting the image of the object; and
in a case where the percentage of the predetermined color component is equal to or more than a threshold, recognize the object including the traffic sign candidate to be the guide sign, wherein:
the storage device is configured to store,
information on a resolution of a camera,
information on specifications of the camera, including information on a mounting height of the camera, and
information on a specified size of the traffic sign candidate; the relative position includes
a relative distance of the traffic sign candidate to the movable body, and
a height of the traffic sign candidate, the height of the traffic sign candidate being obtained by adding the mounting height of the camera to a relative height of the traffic sign candidate to the movable body;
information on the camera image includes information on a plurality of camera images acquired by a plurality of cameras; and
the processor is configured to,
estimate the relative distance by performing calculation by use of the resolution of the camera, the number of pixels constituting the image of the traffic sign candidate in a lateral direction, and the specified size, and
estimate the relative height by performing calculation by use of the relative distance, the resolution of the camera, and the number of pixels constituting the image of the traffic sign candidate in a vertical direction.