Stereo-image processing apparatus
View Patent ↗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.
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 parallax of a subject based on the images taken by the stereo-image taking means;
object detecting means configured to detect objects based on 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 based on a change in 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, wherein
the parallax-offset-value correcting means calculates a parallax error based on the changes in parallax and the apparent size of the object, and corrects the parallax offset value based on the parallax error,
the parallax-offset-value correcting means calculates the parallax error ε according to the following expression when parallax changes from dp 1 to dp 2 and the apparent size of the object changes from b 1 to b 2 :
ε=( b 1 ·dp 2 −b 2 ·dp 1 )/( b 2 −b 1 ), and
the parallax-offset-value correcting means corrects the parallax offset value based on the parallax error ε.
2. The stereo-image processing apparatus according to claim 1 , wherein the parallax-offset-value correcting means forms a histogram for a plurality of parallax errors calculated at different times, and corrects the parallax offset value based on the mode of the histogram.
3. The stereo-image processing apparatus the apparent size of the object is a width of the object in the images.
4. The stereo-image processing apparatus according to claim 1 , wherein
the detected object, which is determined to undergo an apparent change in size, is an object above a road surface.
5. The stereo-image processing apparatus according to claim 4 , further comprising:
taillight distance detecting means configured to detect a distance between right and left taillights of a preceding vehicle, wherein
the object detecting means detects a preceding vehicle as the object whose size in real space does not change,
the parallax-offset-value correcting means corrects the parallax offset value based on a change in 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.
6. The stereo-image processing apparatus according to claim 4 , further comprising:
storage means configured to store parallax and the apparent size of the detected object,
wherein, when the detected object is exchanged, a history of the storage means is cleared.
7. The stereo-image processing apparatus according to claim 6 , wherein an exchange of the detected object is determined to occur when the object detection means detects that a second object entered into the image field of the stereo-image taking means.
8. The stereo-image processing apparatus according to claim 4 , wherein
the stereo-image taking means is configured to take a plurality of images from different viewpoints within an image field,
a determination as to whether the detected object has undergone an apparent change in size is made by a comparing first image data with second image data, and
the detected object is present in the image field during both a first period corresponding to the first image data and a second period corresponding to the second image data.
9. The stereo-image processing apparatus according to claim 1 , wherein the object is a preceding vehicle.
10. 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 parallax of a subject based on the images taken by the stereo-image taking means;
object detecting means configured to detect objects based on 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 based on a change in 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, wherein
the object detecting means detects a preceding vehicle as the object whose size in real space does not change with time, and
the parallax-offset-value correcting means corrects the parallax offset value based on a change in 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; and
the stereo-image processing apparatus 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 based on a change in 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.
11. The stereo-image processing apparatus according to claim 10 , further comprising:
storage means configured to store parallax and the apparent size of the object,
wherein, when the preceding vehicle detected by the object detecting means is exchanged, a history of parallax and the apparent size of the object stored in the storage means is cleared.
12. A stereo-image processing apparatus comprising:
stereo-image taking means configured to take, within an image field, a plurality of images from different viewpoints within the image field;
parallax detecting means configured to detect parallax of a subject based on the images taken by the stereo-image taking means;
object detecting means configured to detect objects based on 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 based on a change in parallax corresponding to a change in an apparent size of an object detected by the object detecting means, which object does not change in size in real space, wherein
a determination as to whether the detected object has undergone an apparent change in size is made by a comparing first image data with second image data,
the detected object is present in the image field during both a first period corresponding to the first image data and a second period corresponding to the second image data,
the parallax-offset-value correcting means calculates a parallax error ε according to the following expression when parallax changes from dp 1 to dp 2 and the apparent size of the object changes from b 1 to b 2 :
ε=( b 1 ·dp 2 −b 2 ·dp 1 )/( b 2 −b 1 ), and
the parallax-offset-value correcting means corrects the parallax offset value based on the parallax error ε.
13. The stereo-image processing apparatus according to claim 12 , further comprising:
taillight distance detecting means configured to detect a distance between right and left taillights of a preceding vehicle, wherein
the object detecting means detects a preceding vehicle as the object whose size in real space does not change,
the parallax-offset-value correcting means corrects the parallax offset value based on a change in 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.
14. The stereo-image processing apparatus according to claim 12 , further comprising:
storage means configured to store parallax and the apparent size of the detected object,
wherein, when the detected object is exchanged, a history of the storage means is cleared.
15. The stereo-image processing apparatus according to claim 14 , wherein an exchange of the detected object is determined to occur when the object detection means detects that a second object entered into the image field of the stereo-image taking means.