Calculation device, camera device, vehicle, and calibration method

Patent metadata

Field	Value
Publication number	US-10373338-B2
Application number	US-201615576781-A
Country	US
Kind code	B2
Filing date	May 26, 2016
Priority date	May 27, 2015
Publication date	Aug 6, 2019
Grant date	Aug 6, 2019

Abstract

A calculation device comprises a controller configured to extract, from a captured image of a subject, a plurality of lines corresponding to straight lines parallel to each other in the subject, and to calculate first calibration data so that mapping lines obtained when the extracted plurality of lines are mapped to a three-dimensional coordinate space are parallel to each other.

First claim

The invention claimed is:

1. A calculation device comprising:
a controller configured to extract, from a captured image of a subject, a plurality of lines corresponding to straight lines parallel to each other located on a plane in the subject, to map the extracted plurality of lines to a three-dimensional coordinate space, and to calculate first calibration data so that mapping lines obtained are parallel to each other,
wherein the controller is configured to calibrate an angle θ C between an optical axis of a camera that captures the image and the plane, based on the first calibration data, and
wherein the mapping of the plurality of lines to the three-dimensional coordinate space is conducted according to the following conversion expressions, when coordinate on the captured image expressed as a pixel value is (u, v), and coordinate on XZ-plane in the three-dimensional coordinate space corresponding to the plane is (X, Z),

Z
=

H
C

·

f
-

(

v
-

v
0

)

⁢

p
·
tan

⁢

⁢

θ
C

f
·
tan

⁢

⁢

θ
C

-

(

v
-

v
0

)

⁢
p

X
=

Z
·

(

u
-

u
0

)

·
p

f

where (u 0 , v 0 ) is a point on the optical axis of the camera in the captured image, H C is height of the camera from the plane, f is focal length of lens of the camera, and p is pixel pitch of the camera.

2. The calculation device according to claim 1 ,
wherein the controller is configured to:
calculate the first calibration data for each of a plurality of captured images of the same subject, the plurality of images having parallax therebetween; and
calculate second calibration data by comparing corresponding mapping lines in the plurality of images.

3. The calculation device according to claim 2 ,
wherein the controller is configured to perform calibration for a parallax deviation between a plurality of cameras that captures the plurality of images, based on the second calibration data.

4. A camera device comprising:
a calculation device including a controller configured to extract, from a captured image of a subject, a plurality of lines corresponding to straight lines parallel to each other located on a plane in the subject, to map the extracted plurality of lines to a three-dimensional coordinate space, and to calculate first calibration data so that mapping lines obtained are parallel to each other; and
one or more cameras configured to capture the image of the subject,
wherein the controller is configured to calibrate an angle θ C between an optical axis of at least one camera of the one or more cameras that captures the image and the plane, based on the first calibration data, and
wherein the mapping of the plurality of lines to the three-dimensional coordinate space is conducted according to the following conversion expressions, when coordinate on the captured image expressed as a pixel value is (u, v), and coordinate on XZ-plane in the three-dimensional coordinate space corresponding to the plane is (X, Z),

Z
=

H
C

·

f
-

(

v
-

v
0

)

⁢

p
·
tan

⁢

⁢

θ
C

f
·
tan

⁢

⁢

θ
C

-

(

v
-

v
0

)

⁢
p

X
=

Z
·

(

u
-

u

Assignees

• Kyocera Corp

Inventors

• Inoue Shushin
• Koishi Tomofumi

Classifications

• H04N2013/0081

  Depth or disparity estimation from stereoscopic image signals · CPC title

• H04N17/002

  for television cameras · CPC title

• H04N13/246

  Calibration of cameras · CPC title

• H04N13/239

  using two two-dimensional [2D] image sensors having a relative position equal to or related to the interocular distance (H04N13/243 takes precedence) · CPC title

• G08G1/166

  for active traffic, e.g. moving vehicles, pedestrians, bikes · CPC title