US-12626393-B2 - Observation device for estimating a distance to an observation target

US12626393B2US 12626393 B2US12626393 B2US 12626393B2US-12626393-B2

Abstract

An observation device 10 includes an imaging device 17 , storage 18 , an acquirer 19 , and a controller 20 . The imaging device 17 generates an image. The storage 18 stores distance information. The distance information is a relationship between an image position and information pertaining to distance. The acquirer 19 acquires position information pertaining to the spatial position of a moving body. When the distance discrepancy between a measured distance and an estimated distance is at or above the first threshold, the controller 20 corrects the distance information using the measured distance. The measured distance corresponds to the position information. The estimated distance is obtained on the basis of the image position of the moving body in the image and the distance information.

Inventors

Toshinobu FUKUDA

Assignees

KYOCERA CORPORATION

Dates

Publication Date: 20260512
Application Date: 20220510
Priority Date: 20210517

Claims (9)

1 . An observation device for estimating a distance to an observation target in a predetermined area, the observation device comprising: an imaging device configured to generate an image through image capture of a space containing the predetermined area; storage configured to store distance information, the distance information being a relationship between an image position in the image captured by the imaging device and information pertaining to the distance; an acquirer configured to acquire, from a moving body, position information pertaining to a spatial position of the moving body; and a controller configured to correct the distance information by using a measured distance corresponding to the position information when a distance discrepancy between the measured distance and an estimated distance is at or above a first threshold, the estimated distance being obtained on a basis of an image position of the moving body in the image and the distance information.
2 . The observation device according to claim 1 , wherein the controller is configured to correct the distance information by using the measured distance to correct information pertaining to a distance corresponding to the image position that corresponds to the estimated distance.
3 . The observation device according to claim 1 , wherein when at least one distance discrepancy for two different image positions is at or above the first threshold, the controller is configured to correct distance information corresponding to an inner image position between the two different image positions by using two measured distances corresponding respectively to the two different image positions corresponding respectively to the two image positions.
4 . The observation device according to claim 3 , wherein the controller is configured to correct an estimated distance corresponding to the inner image position on a basis of a difference between the two measured distances and a difference between two estimated distances corresponding to the two different image positions, a shorter of the two measured distances, and a difference between the shorter of the two measured distances and the estimated distance corresponding to the inner image position.
5 . The observation device according to claim 4 , wherein the controller is configured to: align, with the measured distance, information pertaining to a distance for two image positions corresponding to a position where the measured distance is acquired; and set information pertaining to a distance for a plurality of inner image positions according to a distance in the image to each of the plurality of inner image positions.
6 . The observation device according to claim 3 , wherein the controller is configured to correct the distance information corresponding to the inner image position by using an image position closest to an image position where a distance discrepancy is at or above the first threshold from among image positions where a distance discrepancy is below the first threshold from among image positions where the distance discrepancy is below the first threshold.
7 . The observation device according to claim 1 , wherein when the image contains a plurality of images of moving bodies, the controller is configured to correct the distance information on a basis of the measured distance and an estimated distance that has a smallest difference from the measured distance from among estimated distances corresponding respectively to the plurality of images of moving bodies.
8 . The observation device according to claim 1 , wherein when the distance discrepancy is at or above a second threshold that is higher than the first threshold, the controller is configured to generate warning information warning that the observation device is abnormal.
9 . The observation device according to claim 8 , wherein the controller is configured to: switch an operating mode between an initial setup mode and a normal mode; and correct the distance information without generating the warning information when the distance discrepancy is at or above the second threshold in the initial setup mode, and generate the warning information when the distance discrepancy is at or above the second threshold in the normal mode.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority based on Japanese Patent Application No. 2021-083486 filed May 17, 2021, the entire disclosure of which is hereby incorporated by reference. TECHNICAL FIELD The present disclosure relates to an observation device. BACKGROUND OF INVENTION A known sensor generates an image by capturing a predetermined area, like a camera. Various information may be generated from the image. For example, one proposal involves calculating the distance in a real space to a subject corresponding to a subject image on the basis of an installation orientation relative to the ground, such as a road, and the position of the subject image on the ground in an image (see Patent Literature 1). CITATION LIST Patent Literature Patent Literature 1: Japanese Unexamined Patent Application Publication No. 3-273500 SUMMARY In a first aspect, an observation device estimates a distance to an observation target in a predetermined area. The observation device includes an imaging device, storage, an acquirer, and a controller. The imaging device is configured to generate an image through image capture of a space containing the predetermined area. The storage is configured to store distance information. The distance information indicates a relationship between an image position in the image captured by the imaging device and information pertaining to the distance. The acquirer is configured to acquire, from a moving body, position information pertaining to a spatial position of the moving body. The controller is configured to correct the distance information by using a measured distance corresponding to the position information when a distance discrepancy between the measured distance and an estimated distance is at or above a first threshold. The estimated distance is obtained on a basis of an image position of the moving body in the image and the distance information. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram illustrating an example configuration of a communication system including an observation device according to an embodiment. FIG. 2 is a block diagram illustrating a schematic configuration of the observation device in FIG. 1. FIG. 3 is a state diagram illustrating a fixed state of the observation device in FIG. 1. FIG. 4 is a state diagram for explaining how distance discrepancy occurs due to discrepancy between a real road surface and a virtual plane. FIG. 5 is a first flowchart for explaining a correction process in an initial setup mode executed by the controller in FIG. 2. FIG. 6 is a second flowchart for explaining a correction process in an initial setup mode executed by the controller in FIG. 2. FIG. 7 is a first flowchart for explaining a correction process in a normal mode executed by the controller in FIG. 2. FIG. 8 is a second flowchart for explaining a correction process in a normal mode executed by the controller in FIG. 2. FIG. 9 is a diagram illustrating a distance estimated on the basis of corrected distance information when distance information corresponding to an inner image position is corrected using a measured distance that does not have the smallest difference from the measured distance corresponding to a newly calculated distance discrepancy from among a plurality of measured distances. FIG. 10 is a diagram illustrating a distance estimated on the basis of corrected distance information when distance information corresponding to an inner image position is corrected using a measured distance that has the smallest difference from the measured distance corresponding to a newly calculated distance discrepancy from among a plurality of measured distances. DESCRIPTION OF EMBODIMENTS The following refers to the drawings to describe an embodiment of an observation device to which the present disclosure is applied. FIG. 1 is a diagram illustrating an example configuration of a communication system 11 including an observation device 10 according to an embodiment. The communication system 11 is an Intelligent Transport Systems (ITS) safe driving support communication system, for example. A safe driving support communication system is also referred to as a safe driving support system or a safe driving support wireless system. The observation device 10 may be a device that observes observation targets, such as vehicles, objects, and people, on a road in a predetermined area. The observation device 10 is a roadside unit or a monitoring camera device, for example. In the present embodiment, the observation device 10 is a roadside unit that may be disposed near an intersection where a plurality of roads 12 (streets) intersect to observe the road surface. The observation device 10 may be disposed at a roadside other than an intersection. In the communication system 11, the observation device 10 and a moving body 13, such as an automobile traveling on the roads 12, may communicate with each other wirelessly. A plurality of moving bodies 13 may communicate