System and method for defining a search window

• US 20110019922A1
• Filed: 07/07/2010
• Published: 01/27/2011
• Est. Priority Date: 07/08/2009
• Status: Active Grant

• Current Assignee: Valeo Vision (Valeo SE)
• Original Assignee: Valeo Vision (Valeo SE)
• Inventors: HUE, David, BENSRHAIR, Abdelaziz, AHIAD, Samia
• Granted Patent: US 8,520,952 B2
• Time in Patent Office: Days
• US Class Current: 382/199
• CPC Class Codes: G06T 2207/20132 Image cropping
• CPC Class Codes: G06T 2207/30252 Vehicle exterior; Vicinity of vehicle
• CPC Class Codes: G06T 7/11 Region-based segmentation
• CPC Class Codes: G06V 20/56 exterior to a vehicle by using sensors mounted on the vehicle

Abstract

A system and method for defining a window to search a region of interest for processing a road image, the search window having a longitudinal orientation directed according to the height of the image and being laterally delimited by two edges. The shape of the search window is adapted to the road configuration by defining at least one non-vertical portion on one of the edges. A preferred application is the processing of road images for determining visibility distances in foggy weather.

Claims

1. A method for defining a search window to search a region of interest for processing a road image, the search window having a longitudinal orientation directed according to the height of the image and being laterally delimited by two edges, wherein said method comprises the steps of:

adapting a shape of the search window to the road configuration by defining at least one non-vertical portion on at least one of the edges; and

positioning said non-vertical portion such that it is situated at least partially in a transitional area of the image between a road carriageway and the sky.

2. The method according to claim 1, wherein at least two areas are defined in the search window with:

a bottom area laterally delimited by a low vertical portion of each of the edges;

a second area situated at the top of said bottom area and laterally delimited by the non-vertical portion of each of the edges.

3. The method according to claim 1, wherein the edge comprises a low vertical portion below the non-vertical portion.

4. The method according to claim 1, wherein the non-vertical portion is selected from among:

a horizontal right segment, a right-sloping segment, a curvilinear line portion.

5. The method according to claim 1, wherein at least one non-vertical portion is defined on the other of the edges.

6. The method according to claim 5, wherein the non-vertical portions of the two edges are parallel.

7. The method according to claim 5, wherein three areas are defined in the search window with:

a bottom area laterally delimited by a low vertical portion of each of the edges;

a second area situated at the top of said bottom area and laterally delimited by the non-vertical portion of each of the edges.

8. The method according to claim 7, wherein a third area laterally delimited by a high vertical portion of each one of edges is defined, said second area connecting said bottom area and said third area.

9. The method according to claim 7, wherein the position of a vanishing point PF of a road carriageway is defined and the bottom area is laterally positioned according to the position of the vanishing point PF.

10. The method according to claim 9, wherein the position of the vanishing point PF is obtained by means of a device for detecting the crossing of a white line.

11. The method according to claim 9, wherein the bottom area is laterally centered on the vanishing point PF.

12. The method according to claim 9, wherein the non-vertical edges of said second area are moved and/or deformed according to the direction of the bend, said vanishing PF being inside said second area.

13. The method according to claim 7, wherein a third area laterally delimited by a high vertical portion of each of the edges is defined, said second area connecting said bottom area and said third area and the third area with a lateral offset is positioned relatively to the bottom area, the offset depending on curvature data of a bend of the road carriageway.

14. The method according to claim 7, wherein the position of at least one point of a horizon line of the image is defined and the second area is vertically centered on a point of the horizon line.

15. A method for determining a visibility distance in foggy weather, wherein a region of interest is determined within a search window defined by implementing the method according to any one of the preceding claims, and wherein an average luminance level is determined for a plurality of lines in this region of interest, a luminance profile is deduced therefrom, an inflection point is identified on this luminance profile and a visibility distance is deduced from this inflection point.

16. A system for determining a window to search a region of interest in an image, wherein it comprises a device for acquiring an image and means of processing arranged to implement the method according to claim 1.

17. The system according to claim 16, comprising a device for detecting the crossing of white lines, configured in order to produce data for defining a position of a vanishing point and means for transmitting said data to the means of processing.

18. The method according to claim 2, wherein the edge comprises a low vertical portion below the non-vertical portion.

19. The method according to claim 3, wherein the non-vertical portion is selected from among:

a horizontal right segment, a right-sloping segment, a curvilinear line portion.

20. The method according to claim 2, wherein at least one non-vertical portion is defined on the other of the edges.

21. The method according to claim 6, wherein three areas are defined in the search window with:

a bottom area laterally delimited by a low vertical portion of each of the edges;

a second area situated at the top of said bottom area and laterally delimited by the non-vertical portion of each of the edges.

22. The method according to claim 8, wherein the position of a vanishing point PF of a road carriageway is defined and the bottom area is laterally positioned according to the position of the vanishing point PF.

23. The method according to claim 10, wherein the bottom area is laterally centered on the vanishing point PF.

24. The method according to claim 10, wherein the non vertical edges of said second area are moved and/or deformed according to the direction of the bend, said vanishing PF being inside said second area.

25. The method according to claim 11, wherein the non vertical edges of said second area are moved and/or deformed according to the direction of the bend, said vanishing PF being inside said second area.

26. The method according to claim 8, wherein a third area laterally delimited by a high vertical portion of each of the edges is defined, said second area connecting said bottom area and said third area and the third area with a lateral offset is positioned relatively to the bottom area, the offset depending on curvature data of a bend of the road carriageway.

27. The method according to claim 8, wherein the position of at least one point of a horizon line of the image is defined and the second area is vertically centered on a point of the horizon line.

28. A system for improving a driver'"'"'s ability to navigate a road vehicle, said system comprising:

an image system for capturing a road image;

means for defining a search window to search a region of interest for processing a road image, said search window having a longitudinal orientation directed according to the height of the image and being laterally delimited by two edges;

processor means for adapting a shape of the search window to the road configuration by defining at least one non vertical portion on at least one of the edges and in that this non-vertical portion is positioned such that it is situated at least partially in a transitional area of the image between a road carriageway and the sky.

29. The system according to claim 28, wherein at least two areas are defined in the search window with:

a bottom area laterally delimited by a low vertical portion of each of the edges;

a second area situated at the top of said bottom area and laterally delimited by the non-vertical portion of each of the edges.

30. The system according to claim 28, wherein the edge comprises a low vertical portion below the non-vertical portion.

31. The system according to claim 28, wherein the non-vertical portion is selected from among:

a horizontal right segment, a right-sloping segment, a curvilinear line portion.

32. The system according to claim 28, wherein at least one non-vertical portion is defined on the other of the edges.