Stereo-image processing apparatus

• US 20090046924A1
• Filed: 06/25/2008
• Published: 02/19/2009
• Est. Priority Date: 06/28/2007
• Status: Active Grant

• Current Assignee: Subaru Corp.
• Original Assignee: Fuji Heavy Industries Limited (Subaru Corp.)
• Inventors: Morimitsu, Noboru
• Granted Patent: US 8,417,022 B2
• Time in Patent Office: Days
• US Class Current: 382/154
• CPC Class Codes: G01C 11/06 by comparison of two or more pictures of the same area

Abstract

A stereo-image processing apparatus includes a stereo-image taking means configured to take a plurality of images from different viewpoints, a parallax detecting means configured to detect a parallax of a subject on the basis of the images taken by the stereo-image taking means, an object detecting means configured to detect objects on the basis of the parallax detected by the parallax detecting means and a parallax offset value, and a parallax-offset-value correcting means configured to correct the parallax offset value on the basis of a change in a parallax corresponding to an object whose size in real space does not change with time, of the objects detected by the object detecting means, and a change in an apparent size of the object.

Claims

1. A stereo-image processing apparatus comprising:

stereo-image taking means configured to take a plurality of images from different viewpoints;

parallax detecting means configured to detect a parallax of a subject on the basis of the images taken by the stereo-image taking means;

object detecting means configured to detect objects on the basis of the parallax detected by the parallax detecting means and a parallax offset value; and

parallax-offset-value correcting means configured to correct the parallax offset value on the basis of a change in a parallax corresponding to an object whose size in real space does not change with time, of the objects detected by the object detecting means, and a change in an apparent size of the object.

2. The stereo-image processing apparatus according to claim 1, wherein the parallax-offset-value correcting means calculates a parallax error on the basis of the changes in the parallax and the apparent size of the object, and corrects the parallax offset value on the basis of the parallax error.

3. The stereo-image processing apparatus according to claim 2,

wherein the parallax-offset-value correcting means calculates the parallax error E according to the following expression when the parallax changes from dp₁ to dp₂ and the apparent size of the object changes from b₁ to b₂:

ε

=(b₁·

dp₂−

b₂·

dp₁)/(b₂−

b₁), and

wherein the parallax-offset-value correcting means corrects the parallax offset value on the basis of the parallax error ε

.

4. The stereo-image processing apparatus according to claim 2, wherein the parallax-offset-value correcting means forms a histogram for a plurality of the parallax errors calculated at different times, and corrects the parallax offset value on the basis of the mode of the histogram.

5. The stereo-image processing apparatus according to claim 1,

wherein the object detecting means detects a preceding vehicle as the object whose size in real space does not change with time, and

wherein the parallax-offset-value correcting means corrects the parallax offset value on the basis of a change in a parallax corresponding to the preceding vehicle and a change in an apparent size of the preceding vehicle in the images serving as the apparent size of the object.

6. The stereo-image processing apparatus according to claim 5, further comprising:

storage means configured to store the parallax and the apparent size of the object,

wherein, when the preceding vehicle detected by the object detecting means is exchanged, a history of the parallax and the apparent size of the object stored in the storage means is cleared.

7. The stereo-image processing apparatus according to claim 5, further comprising:

taillight distance detecting means configured to detect a distance between right and left taillights of the preceding vehicle,

wherein the parallax-offset-value correcting means corrects the parallax offset value on the basis of a change in a parallax corresponding to the right and left taillights and a change in an apparent distance in the images between the right and left taillights of the preceding vehicle.

8. The stereo-image processing apparatus according to claim 1, wherein the apparent size of the object is a width of the object in the images.