Method for determining depth maps from stereo images with improved depth resolution in a range

Patent metadata

Field	Value
Publication number	US-9704253-B2
Application number	US-201414655149-A
Country	US
Kind code	B2
Filing date	Jan 14, 2014
Priority date	Jan 14, 2013
Publication date	Jul 11, 2017
Grant date	Jul 11, 2017

Abstract

In a method for determining a depth map from stereo images, the disparity for a pixel is determined from a discrete quantity of predefined disparity values that are distributed over the entire predefined disparity value range. The distribution has at least two different distances between different pairs of adjacent disparity values. In this method, it is possible that only those disparities for which a more precise determination is required, will be more precisely calculated.

First claim

The invention claimed is:

1. A method for determining a depth map from a stereo image pair, wherein a disparity for a pixel is determined from a discrete quantity of predefined disparity values, the predefined disparity values are distributed over an entire predefined disparity value range in a distribution that has at least two different values of distances between respective adjacent disparity values among the predefined disparity values, and the distances between the respective adjacent disparity values are smaller in a far range and larger in a close range.

2. The method according to claim 1 , wherein at least one of the distances has a length below a dimension of the pixel.

3. The method according to claim 2 , wherein comparison/similarity costs for sub-pixel disparities are determined by interpolation from comparison/similarity costs of adjacent integer disparities, and the comparison/similarity costs of the adjacent integer disparities are determined by an appropriate comparison operator from the stereo image pair.

4. The method according to claim 1 , wherein comparison/similarity costs for disparities in the stereo image pair are determined by a suitable comparison operator.

5. The method according to claim 1 , wherein the distances between the respective adjacent disparity values are specified while taking account of effect caused by over- or sub-sampling.

6. The method according to claim 1 , wherein the disparity is determined by a global or semi-global matching or correspondence method.

7. The method according to claim 6 , wherein the disparity is further sub-pixel precisely refined by a minimum disparity based on comparison/similarity costs of the adjacent disparity values after the global or semi-global matching or correspondence method.

8. An apparatus for determining a depth map from a stereo image pair according to the method of claim 1 , said apparatus comprising a stereo camera that is configured and adapted to record the stereo image pair, and a determination unit that is configured and adapted to evaluate the stereo image pair recorded by the stereo camera according to said method.

9. A method for determining a depth map from stereo images, wherein disparities are determined from at least one pair of stereo images, respective values are assigned to the disparities from a predetermined set of potential disparity values that are not uniformly distributed over an entire disparity value range of the potential disparity values, and a distance between two selected adjacent ones of the potential disparity values, in which disparities for a far range are determined, is smaller than a distance between two other adjacent ones of the potential disparity values.

10. An apparatus for determining a depth map from stereo images according to the method of claim 9 , said apparatus comprising a stereo camera that is configured and adapted to record the stereo images, and a determination unit that is configured and adapted to evaluate the stereo images recorded by the stereo camera according to said method.

11. The method according to claim 9 , wherein the far range is at least 10 meters away from a stereo camera with which the stereo images are recorded.

12. The method according to claim 9 , wherein the two other adjacent ones of the potential disparity values are two adjacent disparity values in which disparities for a close range are determined.

13. The method according to claim 12 , wherein the close range is a maximum of 5 meters away from a stereo camera with which the stereo images are recorded.

14. The method according to claim 9 , wherein the disparities are determined by a global or semi-global matching or correspondence method.

15. The method according to claim 9 , wherein at least one distance between two adjacent ones of the potential disparity values is smaller than a dimension of a pixel.

16. The method according to claim 9 , wherein the distance between the two adjacent ones of the potential disparity values is specified while taking account of effects caused by over- or sub-sampling.

17. The method according to claim 9 , wherein similarity costs for the disparities are determined.

18. The method according to claim 17 , wherein the similarity costs of a selected one of the disparities are determined from the similarity costs of the disparities adjacent to the selected disparity.

19. The method according to claim 17 , wherein the similarity costs of a selected one of the disparities are determined directly from the at least one pair of stereo images.

20. The method according to claim 19 , wherein the disparities and the similarity costs thereof are determined only for the distances between two adjacent ones of the disparity values, which correspond to a dimension of one or more pixels.

21. A method for determining a depth map from a stereo image pair, wherein a disparity for a pixel is determined from a discrete quantity of predefined disparity values, the disparity values are distributed over an entire predefined disparity value range in a distribution that has at least two different values of distances between respective adjacent disparity values among the predefined disparity values, a reference image and a search image are produced from the stereo image pair, a resolution of the reference image is reduced by an integer factor k compared to a resolution of the search image, and the disparity is determined with an accuracy of 1/k pixels based on the reference image and the search image.

22. An apparatus for determining a depth map from a stereo image pair according to the method of claim 21 , said apparatus comprising a stereo camera that is configured and adapted to record the stereo image pair, and a determination unit that is configured and adapted to evaluate the stereo image pair recorded by the stereo camera according to said method.

Assignees

• Conti Temic Microelectronic Gmbh

Inventors

• Lange Frederik
• Stueck Robert
• Exner Christian
• Bachmann Alexander
• Baratoff Gregory

Classifications

• G06T7/593 Primary

  from stereo images · CPC title

• G06T7/55

  from multiple images · CPC title

• G06F18/22

  Matching criteria, e.g. proximity measures · CPC title

• G06T7/0075 Primary

  Physics · mapped topic

• G06K9/52

  Physics · mapped topic