MOBILE DETECTOR, MOBILE DETECTING PROGRAM, AND MOBILE DETECTING METHOD

• US 20100260377A1
• Filed: 03/17/2008
• Published: 10/14/2010
• Est. Priority Date: 03/22/2007
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Takahashi, Katsuhiko
• Granted Patent: US 8,509,480 B2
• Time in Patent Office: Days
• US Class Current: 382/103
• CPC Class Codes: G06T 7/254 involving subtraction of images
• CPC Class Codes: G06V 10/25 Determination of region of interest [ROI] or a volume of interest [VOI]
• CPC Class Codes: G06V 20/58 Recognition of moving objects or obstacles, e.g. vehicles or pedestrians; Recognition of traffic objects, e.g. traffic signs, traffic lights or roads

Abstract

When a mobile is detected using an imaging device installed in the mobile, the image of a partial area is enlarged/reduced depending on variation in distance to the detection object mobile and then it is compared under a fixed scale thus causing increase in computation cost. In order to eliminate the need for an enlargement/reduction processing or a deformation correction processing every time when collation is performed, an input image is converted into a virtual plane image having a size or a shape on the image of a detection object mobile which does not vary depending on the distance between the mobiles. Using a pair of virtual plane images obtained at two different times, points are made to correspond and the mobile is detected based on the gap of corresponding points.

Claims

1. A mobile detector, comprising:

a virtual plane image generating device which generates, on an assumption that each pixel of an input image obtained by an imaging device on a mobile corresponds to each point on a virtual plane on a real world parallel to a traveling direction of the mobile, a virtual plane image by converting the input image to an image viewed from a direction perpendicular to the virtual plane; and

a mobile detecting device which relates each of points on two virtual plane images which are generated at two different times, obtains a shift amount between corresponding points, and detects a detection object mobile based on an arrangement of the points having the same shift amount.

2. The mobile detector as claimed in claim 1, wherein

the virtual plane is perpendicular to a road surface.

3. The mobile detector as claimed in claim 1, wherein

the mobile detecting device determines a presence of the detection object mobile when the number of points having the same shift amount in a partial area of the virtual plane image is equal to or more than a predetermined threshold value.

4. The mobile detector as claimed in claim 3, wherein

the partial area is being a segment area which is set along the traveling direction of the image of the detection object mobile so as to include a part of the image of the detection object mobile.

5. The mobile detector as claimed in claim 3, further comprising a mobile passing area extracting device which detects an area in a virtual plane image, which is corresponding to an area in a plane where the detection object mobile passes, as a mobile passing area, wherein

the mobile detecting device determines the presence of the detection object mobile when the number of points having the same shift amount in a partial area on the virtual plane image is equal to or more than a predetermined threshold value and one or more point having the same shift amount is detected from the mobile passing area.

6. The mobile detector as claimed in claim 1, wherein

the mobile mounting the imaging device is being a vehicle, and the detection object mobile is being another vehicle traveling on a lane neighboring to a lane where the vehicle mounting the imaging device is traveling.

7. The mobile detector as claimed in claim 3, wherein

a size of the partial area in the virtual plane image is settable according on the length of the detection object mobile.

8. A mobile detector, comprising:

a virtual line image generating device which generates, on an assumption that each pixel of an input image obtained by an imaging device on a mobile corresponds to each point on a virtual line on a real world parallel to a traveling direction of the mobile, a virtual line image by converting the input image to an image viewed from a direction perpendicular to the virtual line; and

a mobile detecting device which relates each of points on two virtual line images which are generated at two different times, obtains a shift amount between corresponding points, and detects the detection object mobile based on an arrangement of the points having the same shift amount.

9. A computer readable recording medium storing a mobile detecting program causing a computer connected to an imaging device installed on a mobile to execute:

a virtual plane image generating function for generating, on an assumption that each pixel of an input image obtained by an imaging device corresponds to each point on a virtual plane on a real world parallel to a traveling direction of the mobile, a virtual plane image by converting the input image to an image viewed from a direction perpendicular to the virtual plane; and

a mobile detecting function for relating each of points on two virtual plane images which are generated at two different times, obtaining a shift amount between corresponding points, and detecting the detection object mobile based on an arrangement of the points having the same shift amount.

10. The computer readable recording medium storing the mobile detecting program as claimed in claim 9, wherein

the input image is converted, by the virtual plane image generating function, to an image viewed from a perpendicular direction to the virtual plane on the real world which is perpendicular to a road surface.

11. The computer readable recording medium storing the mobile detecting program as claimed in claim 9, wherein

the presence of the detection object mobile is determined, by the mobile detecting function, when the number of points having the same shift amount in a partial area of the virtual plane image is equal to or more than a predetermined threshold value.

12. The computer readable recording medium storing the mobile detecting program as claimed in claim 11, wherein

the partial area is set to be a segment area which extends along the traveling direction of the image of the detection object mobile so as to include a part of the image of the detection object mobile, by the mobile detecting function.

14. The computer readable recording medium storing the mobile detecting program as claimed in claim 11, causing a computer to execute an area setting function for setting a size of the partial area in the virtual plane image according on the length of the detection object mobile.

13. A computer readable recording medium storing a mobile detecting program causing a computer connected to an imaging device installed on a mobile to execute:

a virtual plane image generating function for generating, on an assumption that each pixel of an input image obtained by an imaging device corresponds to each point on a virtual plane on a real world parallel to a traveling direction of the mobile, a virtual plane image by converting the input image to an image viewed from a direction perpendicular to the virtual plane;

a mobile passing area extracting function for detecting an area in a virtual plane image, which is corresponding to an area in a plane where the detection object mobile passes, as a mobile passing area; and

a mobile detecting function for relating each of points on two virtual plane images which are generated at two different times, obtaining a shift amount between corresponding points, and determining a presence of the detection object mobile when the number of points having the same shift amount in a partial area on the virtual plane image is equal to or more than a predetermined threshold value and one or more point having the same shift amount is detected from the mobile passing area.

15. A computer readable recording medium storing a mobile detecting program causing a computer connected to an imaging device installed on a mobile to execute:

a virtual line image generating function for generating, on an assumption that each pixel of an input image obtained by an imaging device corresponds to each point on a virtual line on a real world parallel to a traveling direction of the mobile, a virtual line image by converting the input image to an image viewed from a direction perpendicular to the virtual line; and

a mobile detecting function for relating each of points on two virtual line images which are generated at two different times, obtaining a shift amount between corresponding points, and detecting the detection object mobile based on an arrangement of the points having the same shift amount.

16. A mobile detecting method, comprising:

taking in an image at every predetermined cycle by an imaging device installed on a mobile;

generating, on an assumption that each pixel of an input image obtained by an imaging device on a mobile corresponds to each point on a virtual plane on a real world parallel to a traveling direction of the mobile, a virtual plane image by converting the input image to an image viewed from a direction perpendicular to the virtual plane;

relating the points on the virtual plane image generated immediately before to the points on the virtual plane image generated currently to obtain a shift amount between corresponding points; and

detecting the detection object mobile based on an arrangement of the points having the same shift amount.

17. The mobile detecting method as claimed in claim 16, comprising:

converting the input image to an image viewed from a direction perpendicular to the virtual plane on the real world, which is perpendicular to a road surface, when generating the virtual plane image.

18. The mobile detecting method as claimed in claim 16, comprising:

determining the presence of the detection object mobile when the number of points having the same shift amount in a partial area on the virtual plane image is equal to or more than a predetermined threshold value.

19. The mobile detecting method as claimed in claim 18, comprising:

setting the partial area as a segment area which extends along the traveling direction of the image of the detection object mobile so as to include a part of the image of the detection object mobile.

21. The mobile detecting method as claimed in claim 18, comprising:

setting a size of the partial area in the virtual plane image according on the length of the detection object mobile.

20. A mobile detecting method, comprising:

taking in an image at every predetermined cycle by an imaging device installed on a mobile;

generating, on an assumption that each pixel of an input image obtained by an imaging device on a mobile corresponds to each point on a virtual plane on a real world parallel to a traveling direction of the mobile, a virtual plane image by converting the input image to an image viewed from a direction perpendicular to the virtual plane;

detecting an area in a virtual plane image, which is corresponding to an area in a plane where the detection object mobile passes, as a mobile passing area;

relating the points on the virtual plane image generated immediately before to the points on the virtual plane image generated currently to obtain a shift amount between corresponding points; and

determining a presence of the detection object mobile when the number of points having the same shift amount in a partial area on the virtual plane image is equal to or more than a predetermined threshold value and one or more point having the same shift amount is detected from the mobile passing area.

22. A mobile detecting method, comprising:

taking in an image at every predetermined cycle by an imaging device installed on a mobile;

generating, on an assumption that each pixel of an input image obtained by an imaging device on a mobile corresponds to each point on a virtual plane on a real world parallel to a traveling direction of the mobile, a virtual line image by converting the input image to an image viewed from a direction perpendicular to the virtual line;

relating the points on the virtual line image generated immediately before to the points on the virtual line image generated currently to obtain a shift amount between corresponding points; and

detecting the detection object mobile based on an arrangement of the points having the same shift amount.

23. A mobile detector, comprising:

virtual plane image generating means for generating, on an assumption that each pixel of an input image obtained by an imaging device on a mobile corresponds to each point on a virtual plane on a real world parallel to a traveling direction of the mobile, a virtual plane image by converting the input image to an image viewed from a direction perpendicular to the virtual plane; and

mobile detecting means for relating each of points on two virtual plane images which are generated at two different times, obtaining a shift amount between corresponding points, and detecting a detection object mobile based on an arrangement of the points having the same shift amount.

24. A mobile detector, comprising:

virtual line image generating means for generating, on an assumption that each pixel of an input image obtained by an imaging device on a mobile corresponds to each point on a virtual line on a real world parallel to a traveling direction of the mobile, a virtual line image by converting the input image to an image viewed from a direction perpendicular to the virtual line; and

mobile detecting means for relating each of points on two virtual line images which are generated at two different times, obtaining a shift amount between corresponding points, and detecting the detection object mobile based on an arrangement of the points having the same shift amount.