Stereoscopic image characteristics examination system

• US 20030169918A1
• Filed: 03/04/2003
• Published: 09/11/2003
• Est. Priority Date: 03/06/2002
• Status: Active Grant

• Current Assignee: Subaru Corp.
• Original Assignee: Fuji Jukogyo KK (Subaru Corp.)
• Inventors: Sogawa, Yoshiyuki
• Granted Patent: US 7,139,424 B2
• Time in Patent Office: Days
• US Class Current: 382/154
• CPC Class Codes: G06T 2207/30168 Image quality inspection
• CPC Class Codes: G06T 5/80 Geometric correction
• CPC Class Codes: G06T 7/85 Stereo camera calibration
• CPC Class Codes: H04N 13/239 using two 2D image sensors having a relative position equal to or related to the interocular distance H04N13/243 takes precedence
• CPC Class Codes: H04N 13/246 Calibration of cameras
• CPC Class Codes: H04N 2013/0081 Depth or disparity estimation from stereoscopic image signals

Abstract

A stereo camera and an examination screen having a pattern based on grid lines are arranged at prescribed positions relative to each other. The stereo camera photographs the examination screen to obtain two original images. A stereoscopic image characteristics detection unit obtains the coordinates of each grid point on each image. A correction data generation unit generates correction data for correcting a variation in the image characteristics on the basis of the obtained coordinates and the corresponding ideal coordinates stored previously of each grid point. A correction data writing unit writes the generated correction data into a stereoscopic image recognition unit. Thus, prior to shipment of the stereo camera and the stereoscopic image recognition unit or upon readjustment after shipment, the characteristics of an stereoscopic image are examined to obtain high-accurate correction data. The high-level capability of the stereo camera is maintained using the correction data.

Claims

1. A stereoscopic image characteristics examination system for examining the characteristics of a stereoscopic image captured by a stereo camera having a plurality of cameras and for generating correction data, the system comprising:

an examination screen having a grid pattern, and said screen arranged in the shooting direction of the stereo camera; and

means for obtaining the coordinates of each grid point on each of images constituting a stereoscopic image obtained by photographing the examination screen with the stereo camera, the images corresponding to the respective cameras constituting the stereo camera, and for generating correction data for correcting a variation in the characteristics of the stereoscopic image on the basis of the obtained coordinates and the corresponding ideal coordinates previously stored of each grid point, the variation being caused by at least the characteristics of the stereo camera.

2. The system according to claim 1, wherein a correlation value between an image pattern on the examination screen and a previously stored pattern is calculated to search for a matching point so as to obtain the coordinate of each grid point on each image.

3. The system according to claim 1, wherein a reference mark corresponding to each camera is provided on the examination screen, the reference mark is initially searched, and adjacent grid points are sequentially detected to obtain the coordinates of the grid points on each image.

4. The system according to claim 1, wherein each grid line on the examination screen is formed so as to have a gradation, of which lightness varies in at least one of a multi-step manner and continuously from the center of the grid line to the background.

5. The system according to claim 1, wherein in the examination screen, the lightness of the grid line is higher than that of the background.

6. The system according to claim 1, wherein the correction data is at least one of image-coordinate-transformation correction data, parallax correction data based on the view-angle correction ratio, and matching-point search-range correction data.

7. The system according to claim 1, further comprising:

means for capturing the stereoscopic image from the stereo camera through an image processing unit, which is combined with the stereo camera in a one-to-one relationship and for writing the correction data in a non-volatile memory in the image processing unit.

8. A stereoscopic image characteristics examination system for examining the characteristics of a stereoscopic image and for generating correction data, the system comprising:

a plurality of cameras for obtaining each image constituting the stereoscopic image of an examination screen having a grid pattern provided in the shooting direction thereof;

means for obtaining the coordinates of each grid point on each of said images; and

means for generating correction data for correcting a variation in the characteristics of the stereoscopic image on the basis of the obtained coordinates and the corresponding ideal coordinates previously stored of each grid point, the variation being caused by at least the characteristics of the stereo camera.