Moving-object position/attitude estimation apparatus and moving-object position/attitude estimation method

• US 9,797,981 B2
• Filed: 02/28/2013
• Issued: 10/24/2017
• Est. Priority Date: 03/06/2012
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Yamaguchi, Ichiro, Kojo, Naoki
• Primary Examiner(s): Patel, Jay
• Assistant Examiner(s): MATT, MARNIE A
• Application Number:
  US14/383,012
• Publication Number:
  US 20150015702A1
• Time in Patent Office: 1,699 Days
• Field of Search: 348142
• CPC Class Codes: G01S 3/7864 T.V. type tracking systems
• CPC Class Codes: G06T 17/05 Geographic models
• CPC Class Codes: G06T 2207/30244 Camera pose
• CPC Class Codes: G06T 2207/30252 Vehicle exterior; Vicinity of vehicle
• CPC Class Codes: G06T 7/74 involving reference images or patches
• CPC Class Codes: G06V 20/56 exterior to a vehicle by using sensors mounted on the vehicle
• CPC Class Codes: H04N 7/18 Closed-circuit television [CCTV] systems, i.e. systems in which the video signal is not broadcast
• CPC Class Codes: H04N 7/181 for receiving images from a plurality of remote sources

Abstract

A moving-object position/attitude estimation apparatus includes: an image-capturing unit configured to acquire a captured image; a comparative image acquiring unit configured to acquire a comparative image viewed from a predetermined position at a predetermined attitude angle; a likelihood setting unit configured to compare the captured image with the comparative image and to assigns a high attitude angle likelihood to the comparative image and to assigns a high position likelihood to the comparative image; a moving-object position/attitude estimation unit configured to estimate the attitude angle of the moving object based on the attitude angle of the comparative image assigned the high attitude angle likelihood and to estimate the position of the moving object based on the position of the comparative image assigned the high position likelihood.

Claims

1. A moving-object position/attitude estimation apparatus for estimating a position and an attitude angle of a moving object, comprising:

an image-capturing circuitry configured to acquire a captured image by capturing an image of surroundings of the moving object;

a comparative image acquiring circuitry configured to acquire a comparative image viewed from a predetermined position at a predetermined attitude angle;

a likelihood setting circuitry configured to compare the captured image acquired by the image-capturing circuitry with the comparative image acquired by the comparative image acquiring circuitry and set a higher position likelihood or a higher attitude angle likelihood as a number of pixels at which edges on an edge image calculated from the captured image are located at pixel coordinate positions of edges on the comparative image increases, and to assign a high attitude angle likelihood to the comparative image in a case where a distant-position pixel in the captured image matches a distant-position pixel in the comparative image and assign a high position likelihood to the comparative image in a case where a proximal-position pixel in the captured image matches a proximal-position pixel in the comparative image; and

a moving-object position/attitude estimation circuitry configured to estimate the attitude angle of the moving object based on the attitude angle of the comparative image assigned the high attitude angle likelihood by the likelihood setting circuitry and estimate the position of the moving object based on the position of the comparative image assigned the high position likelihood by the likelihood setting circuitry.

2. The moving-object position/attitude estimation apparatus according to claim 1, wherein

the comparative image acquiring circuitry is a virtual image acquisition circuitry configured to acquire a virtual image by converting three-dimensional map data to an image captured from a virtual position at a virtual attitude angle,

the likelihood setting circuitry compares the captured image acquired by the image-capturing circuitry with the virtual image acquired by the virtual image acquisition circuitry and sets the higher position likelihood or the higher attitude angle likelihood as the number of pixels at which edges on the edge image calculated from the captured image are located at pixel coordinate positions of edges on the virtual image increases, assigns a high attitude angle likelihood to the virtual image in a case where a distant-position pixel in the captured image matches a distant-position pixel in the virtual image, and assigns a high position likelihood to the virtual image in a case where a proximal-position pixel in the captured image matches a proximal-position pixel in the virtual image, and

the moving-object position/attitude estimation circuitry estimates the attitude angle of the moving object based on the virtual attitude angle of the virtual image assigned the high attitude angle likelihood by the likelihood setting circuitry, and estimates the position of the moving object based on the virtual position of the virtual image assigned the high position likelihood by the likelihood setting circuitry.

3. The moving-object position/attitude estimation apparatus according to claim 1, wherein

the comparative image acquiring circuitry acquires as the comparative image the captured image captured in the past by the image-capturing circuitry, and

the moving-object position/attitude estimation circuitry estimates the attitude angle of the moving object based on an attitude angle at which the moving object was when the comparative image assigned the high attitude angle likelihood by the likelihood setting circuitry was captured, and estimates the position of the moving object based on a position where the moving object was located when the comparative image assigned the high position likelihood by the likelihood setting circuitry was captured.

4. The moving-object position/attitude estimation apparatus according to claim 1, wherein in a case where among distant-position pixels in the captured image and the comparative image, a pixel in the captured image and a pixel in the comparative image match each other at a more distant position located at or beyond a predetermined distance from the moving object, the likelihood setting circuitry sets the attitude angle likelihood of the comparative image such that the likelihood is set to a predetermined upper limit.

5. The moving-object position/attitude estimation apparatus according to claim 1, wherein in a case where among proximal-position pixels in the captured image and the comparative image, a pixel in the captured image and a pixel in the comparative image match each other at a nearer position located at or within a predetermined distance from the moving object, the likelihood setting circuitry sets the position likelihood of the comparative image such that the likelihood is set to a predetermined upper limit.

6. The moving-object position/attitude estimation apparatus according to claim 2, wherein

the virtual image acquisition circuitry generates plural candidate points each set to have a virtual position and a virtual attitude angle and acquires a virtual image for each of the candidate points;

the likelihood setting circuitry compares each of the virtual images with the captured image and assigns an attitude angle likelihood and a position likelihood; and

the moving-object position/attitude estimation circuitry estimates the attitude angle of the moving object based on the attitude angle likelihoods of the virtual images and estimates the position of the moving object based on the position likelihoods of the virtual images, and

the virtual image acquisition circuitry performs resampling of the plural candidate points based on the attitude angle likelihoods of the virtual images and the position likelihoods of the virtual images.

7. The moving-object position/attitude estimation apparatus according to claim 1, wherein

the comparative image acquiring circuitry sets plural positions and acquires the comparative image of a region located at or within a predetermined distance from the moving object for each of the positions,

the likelihood setting circuitry compares each of the comparative images of the region located at or within the predetermined distance from the moving object with the captured image and assigns a higher position likelihood to the comparative image as the number of pixels at which edges on the edge image calculated from the captured image are located at pixel coordinate positions of edges on the comparative image increases,

the moving-object position/attitude estimation circuitry estimates the position of the moving object based on the position of the comparative image assigned the higher position likelihood by the likelihood setting circuitry,

the comparative image acquiring circuitry sets plural attitude angles and acquires the comparative image of a region located at or beyond a predetermined distance away from the moving object for each of the attitude angles,

the likelihood setting circuitry compares each of the comparative images of the region located at or beyond the predetermined distance away from the moving object with the captured image and assigns a higher attitude angle likelihood to the comparative image as the number of pixels at which edges on the edge image calculated from the captured image are located at the pixel coordinate positions of edges on the comparative image increases, and

the moving-object position/attitude estimation circuitry estimates the attitude angle of the moving object based on the attitude angle of the comparative image assigned the higher attitude angle likelihood by the likelihood setting circuitry.

8. A moving-object position/attitude estimation method for estimating a position and an attitude angle of a moving object, comprising:

comparing a captured image obtained by capturing an image of surroundings of the moving object with a comparative image viewed from a predetermined position at a predetermined attitude angle and setting a higher position likelihood or a higher attitude angle likelihood as a number of pixels at which edges on an edge image calculated from the captured image are located at pixel coordinate positions of edges on the comparative image increases;

assigning a high attitude angle likelihood to the comparative image in a case where a distant-position pixel in the captured image matches a distant-position pixel in the comparative image and assigning a high position likelihood to the comparative image in a case where a proximal-position pixel in the captured image matches a proximal-position pixel in the comparative image; and

estimating the attitude angle of the moving object based on the attitude angle of the comparative image assigned the high attitude angle likelihood and estimating the position of the moving object based on the position of the comparative image assigned the high position likelihood.