CALIBRATION DEVICE AND CALIBRATION METHOD FOR RANGE IMAGE SENSOR

• US 20090222229A1
• Filed: 02/19/2009
• Published: 09/03/2009
• Est. Priority Date: 02/28/2008
• Status: Active Grant

• Current Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.)
• Original Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.)
• Inventors: KAKINAMI, Toshiaki
• Granted Patent: US 7,822,571 B2
• Time in Patent Office: Days
• US Class Current: 702/97
• CPC Class Codes: G01S 17/894 3D imaging with simultaneous measurement of time-of-flight at a 2D array of receiver pixels, e.g. time-of-flight cameras or flash lidar
• CPC Class Codes: G01S 17/931 of land vehicles
• CPC Class Codes: G01S 7/497 Means for monitoring or calibrating

Abstract

A calibration device for calibrating a range image sensor, detecting a distance of each direction within a detection range and generating a range image data, in a state where the range image sensor is attached at a mobile body, the calibration device includes a data receiving portion for receiving a calibration-subject data including a calibration target, which is set within the detection range and includes a first plane surface and a second plane surface, from the range image sensor, a plane surface specifying portion for specifying each of the first and second plane surfaces in a three-dimensional reference coordinate system, a normal vector calculating portion for three-dimensionally calculating a normal vector of each of the first and second plane surfaces, and a rotation calculating portion for three-dimensionally calculating a rotation of the range image sensor on the basis of an already-recognized posture information and the normal vector.

Claims

1. A calibration device for a range image sensor, the calibration device being configured so as to calibrate the range image sensor, which is attached at a mobile body, detects a distance of each direction within a detection range and generates a range image data from the detected distance information, in a state where the range image sensor is attached at the mobile body, the calibration device comprising:

a data receiving portion for receiving a calibration-subject data, which is the range image data including a calibration target, from the range image sensor, the calibration target being set within the detection range and is configured so as to include a first plane surface and a second plane surface, which differs from the first plane surface;

a plane surface specifying portion for specifying each of the first plane surface and the second plane surface in a three-dimensional reference coordinate system on the basis of the calibration-subject data;

a normal vector calculating portion for calculating a normal vector of each of the specified first and second plane surfaces in the three-dimensional reference coordinate system; and

a rotation calculating portion for calculating a rotation of the range image sensor in the three-dimensional reference coordinate system on the basis of a posture information, which has already been recognized, and the normal vector in the three-dimensional coordinate system.

2. The calibration device for the range image sensor according to claim 1, wherein the calibration device specifies an approximate position of the calibration target relative to the detection range and calibrates the range image sensor under a condition where a position information of the calibration target, a position information of the mobile body, which is in a stationary state at a predetermined position, and the posture information of the calibration target in the three-dimensional reference coordinate system have already been recognized.

3. The calibration device for the range image sensor according to claim 1, wherein the calibration device calibrates the range image sensor in a state where a position information of the calibration target, a position information of the mobile body, which is in a stationary state at a predetermined position, and the posture information of the calibration target in the three-dimensional reference coordinate system have already been recognized, and wherein the calibration device further includes a distance information extracting portion for extracting the distance information relating to each of the first and second plane surfaces from the calibration-subject data on the basis of the position information of the calibration target, the position information of the mobile body and the posture information of the calibration target, so that the plane surface specifying portion specifies each of the first and second plane surfaces by using the extracted distance information.

4. The calibration device for the range image sensor according to claim 1, wherein the calibration target is configured so as to include an intersecting portion, at which the first and second plane surfaces intersect with each other, and so that an intersection, at which at least one of first and second plane surface end portions of the respective first and second plane surfaces intersects with the intersecting portion, is set at the position, which has already been recognized in the three-dimensional reference coordinate system, the plane surface specifying portion further specifies each of the first and second plane surface end portions, which intersect with the intersecting portion, and wherein the calibration device further includes an intersection coordinate calculating portion for calculating an intersection coordinate, at which the first and second plane surface end portions of the respective first and second plane surfaces specified by the plane surface specifying portion intersect with each other, in the three-dimensional reference coordinate system, and a translation calculating portion for calculating a translation of the range image sensor in the three-dimensional reference coordinate system on the basis of a position information of the intersection and the intersection coordinate in the three-dimensional reference coordinate system.

5. The calibration device for the range image sensor according to claim 1, wherein the calibration target is configured so as to further include a third plane surface, which differs from the first and second plane surfaces, and an intersection, at which the first, second and third plane surfaces, intersect with each other, the plane surface specifying portion further specifies the third plane surface in the three-dimensional reference coordinate system, and wherein the calibration device further includes an intersection coordinate calculating portion for calculating an intersection coordinate, at which the first, second and third plane surfaces, specified at the plane surface specifying portion, intersect with each other, in the three-dimensional reference coordinate system, and a translation calculating portion for calculating a translation of the range image sensor in the three-dimensional reference coordinate system on the basis of a position information of the intersection and the intersection coordinate in the three-dimensional reference coordinate system.

6. The calibration device for the range image sensor according to claim 5 further including a distance information extracting portion for extracting the distance information relating to each of the first, second and third plane surfaces, wherein the plane surface specifying portion specifies each of the first, second, and third plane surfaces by using the extracted distance information.

7. The calibration device for the range image sensor according to claim 1, wherein the first and second plane surfaces are surfaces, which are orthogonal to each other.

8. The calibration device for the range image sensor according to claim 5, wherein the first, second and third plane surfaces are surfaces, which are orthogonal to each other.

9. The calibration device for the range image sensor according to claim 1, wherein the calibration target is set in a state where at least one of the first and the second plane surfaces of the calibration target is orthogonal relative to or in parallel with one axis of the three-dimensional reference coordinate system.

10. A calibration method for a range image sensor, the calibration method calibrating the range image sensor, which is attached at a mobile body, detects a distance of each direction within a detection range and generates a range image data from the detected distance information, in a state where the range image sensor is attached at the mobile body, the calibration method comprising;

a mobile body setting process for setting the mobile body at a predetermined position in a three-dimensional reference coordinate system in a stationary state;

a calibration target setting process for setting a calibration target within the detection range in a state where a position information of the calibration target relative to the mobile body and a posture information of the calibration target is specified in the three-dimensional reference coordinate system, the calibration target being configured so as to include a first plane surface and a second plane surface, which differs from the first plane surface;

a data receiving process for receiving a calibration-subject data from the range image sensor, the calibration-subject data being a range image data generated by the range image sensor in a state where the mobile body is in the stationary state at the predetermined position and including the calibration target;

a plane surface specifying process for specifying each of the first and second plane surfaces in the three-dimensional reference coordinate system on the basis of the calibration-subject data;

a normal vector calculating process for calculating a normal vector of each of the specified first and second plane surfaces in the three-dimensional reference coordinate system; and

a rotation calculating process for calculating a rotation of the range image sensor in the three-dimensional reference coordinate system on the basis of the posture information of the calibration target and the normal vector of each of the specified first and second plane surfaces in the three-dimensional reference coordinate system.

11. The calibration method for the range image sensor according to claim 10, wherein the calibration target further includes a third plane surface, which differs from the first and second plane surfaces, the plane surface specifying process further specifies the third plane surface in the thee-dimensional reference coordinate system, and wherein the calibration method further includes an intersection coordinate calculating process for calculating an intersection coordinate, at which the first, second and third plane surfaces specified by the plane surface specifying process intersect with each other, in the three-dimensional coordinate system, and a translation calculating portion for calculating a translation of the range image sensor in the three-dimensional coordinate system on the basis of the position information and the intersection coordinate in the three-dimensional reference coordinate system.