Camera parameter calculation device, navigation system and camera parameter calculation method

Patent metadata

Field	Value
Publication number	US-9948853-B2
Application number	US-201314419369-A
Country	US
Kind code	B2
Filing date	Aug 1, 2013
Priority date	Aug 3, 2012
Publication date	Apr 17, 2018
Grant date	Apr 17, 2018

Abstract

A device for calculating one or more camera parameters of a camera mounted on a traveling vehicle includes a location information acquisition unit, a road width information acquisition unit, a scenery image acquisition unit, and a camera parameter calibration unit. The device calculates a height of a mount position of the camera and a direction of the camera. The device also converts a scenery image captured by the camera of a scenery including the road on which the traveling vehicle moves into an image that is displayed for navigation.

First claim

The invention claimed is:

1. A device for calculating one or more camera parameters, the device comprising:
a camera;
a location information acquisition unit that acquires location information about a current location of the traveling vehicle;
a road width information acquisition unit that acquires road data corresponding to the current location based on the location information and acquires road width information relating to a width of a road on which the traveling vehicle moves at the current location from the road data;
a scenery image acquisition unit that acquires a scenery image from the camera;
a camera parameter calibration unit that performs calibration calculation of the one or more camera parameters based on the scenery image and the road width information, wherein
the device converts the scenery image captured by the camera of a scenery including the road on which the traveling vehicle moves,
the one or more camera parameters that are calculated include a height of a mount position of the camera relative to the road and a direction of the camera; and

displaying on a screen the converted scenery image, wherein
the height of the mount position of the camera is calculated based on a ratio of a road width as displayed on the screen to the width of the road wherein the camera parameter calibration unit performs calibration calculation when a road condition determination unit determines that the road satisfies predetermined road conditions based on each of the following:
i) the width of the road around the current location,
ii) a number of lanes of the road around the current location,
iii) whether a road type of the road around the current location is classified into a narrow street,
iv) a link type of a link related to the road around the current location,
v) an inclination of the road around the current location,
vi) a curvature of the road around the current location, and
vii) a connection angle formed between a link related to the road around the current location and another link connected thereto.

2. The device for calculating one or more camera parameters according to claim 1 , further comprising:
a prediction image creation unit that creates a prediction image of the scenery based on the location information and the road data acquired by the road width information acquisition unit and extracts a first feature part included in the prediction image;
a first conversion unit that creates a first scenery conversion image by converting coordinates of the scenery image based on the one or more camera parameters;
a feature extraction unit that extracts a second feature part from the first scenery conversion image by image processing calculation; and
a similarity determination unit that determines whether or not the first feature part acquired by the prediction image creation unit is similar to the second feature part acquired by the feature extraction unit, wherein
if the similarity determination unit determines that the first feature part is dissimilar to the second feature part, the camera parameter calibration unit performs calibration calculation of the one or more camera parameters.

3. The device for calculating one or more camera parameters according to claim 2 , further comprising:
a road data acquisition unit that acquires the road data corresponding to the current location; and
the road condition determination unit that determines whether or not the road satisfies predetermined road conditions around the current location based on the road data, wherein
if the road condition determination unit determines that the road satisfies the predetermined road conditions, the camera parameter calibration unit performs calibration calculation of the one or more camera parameters.

4. A navigation system comprising the a device for calculating one or more camera parameters according to claim 1 ;
a camera connection unit to which the camera is operable to be attached for connection to enable the scenery image captured by the camera to be acquired by the scenery image acquisition unit; and
a second conversion unit that creates a second scenery conversion image by conversion of coordinates of the scenery image based on the one or more camera parameters obtained by calibration calculation by the camera parameter calibration unit.

5. The navigation system according to claim 4 , further comprising:
a route search unit that searches a recommended route from the current location to a destination;
a route guide information creation unit that creates route guide information for guiding the traveling vehicle to the destination along the recommended route based on the recommended route and the second scenery conversion image using the second scenery conversion image; and
a route guide unit that guides the traveling vehicle along the recommended route to the destination based on the route guide information created by the route guide information creation unit.

6. The navigation system according to claim 5 , further comprising:
a moving body state recognition unit
that calculates an estimated distance from the current location to a crossing on the road around the current location or to another traveling vehicle in front of the traveling vehicle based on the second scenery conversion image, a focal distance of the camera, and the one or more camera parameters subjected to calibration calculation by the camera parameter calibration unit and
that recognizes a moving state of the traveling vehicle by recognizing a lane, which is included in the scenery image and on which the moving body moves, based on a type of a line drawn on each of both edges of the lane by image processing, wherein
the route guide information creation unit creates the route guide information based on the estimated distance and the lane recognized by the moving state recognition unit and based on the second scenery conversion image.

7. The device for calculating one or more camera parameters according to claim 1 , wherein the one or more camera parameters also include a yaw angle, pitch angle and roll angle corresponding to rotation angles that make an angle of image capturing identical to a posture of the vehicle by rotational motion.

8. A method of calculating one or more camera parameters, the method comprising:
mounting a camera on a vehicle;
acquiring location information about a current location of the vehicle;
acquiring road data corresponding to the current location based on the location information;
acquiring road width information about a road width of a road on which the vehicle moves at the current location;
acquiring a scenery image from the camera;
executing calibration calculation of the one or more camera parameters based on the scenery image and the road width information;
converting the scenery image captured by the camera of a scenery including the road on which the vehicle moves into a navigation image;
calculating at least a height of a mount position of the camera relative to the road and a direction of the camera; and
displaying on a screen the converted scenery image, wherein
the height of the mount position of the camera is calculated based on a ratio of a road width as displayed on the screen to the road width wherein the executing calibration calculation occurs when the road satisfies predetermined road conditions based on each of the following:
i) the width of the road around the current location,
ii) a number of lanes of the road around the current location,
iii) whether a road type of the road around the current location is classified into a narrow street,
iv) a link type of a link related to the road around the current location,
v) an inclination of the road around the current location,
vi) a curvature of

Assignees

• Clarion Co Ltd

Inventors

• Okude Mariko
• Hiruta Tomoaki
• Amaya Shinichi
• Shima Takeshi

Classifications

• H04N23/62 Primary

  Control of parameters via user interfaces · CPC title

• G09B29/10

  Map spot or coordinate position indicators; Map reading aids (optical projection apparatus per se G03B) · CPC title

• H04N5/23216 Primary

  Electricity · mapped topic

• G01C21/3602 Primary

  Input other than that of destination using image analysis, e.g. detection of road signs, lanes, buildings, real preceding vehicles using a camera · CPC title

• G06T2207/30256

  Lane; Road marking · CPC title