Image processing device

• US 10,185,879 B2
• Filed: 03/16/2015
• Issued: 01/22/2019
• Est. Priority Date: 04/15/2014
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Sakamoto, Yosuke
• Primary Examiner(s): Le, Vu
• Assistant Examiner(s): Rivera-Martinez, Guillermo M
• Application Number:
  US14/658,482
• Publication Number:
  US 20150294163A1
• Time in Patent Office: 1,408 Days
• Field of Search: None
• CPC Class Codes: G06T 2207/30256 Lane; Road marking
• CPC Class Codes: G06T 7/12 Edge-based segmentation
• CPC Class Codes: G06T 7/136 involving thresholding
• CPC Class Codes: G06V 20/588 Recognition of the road, e.g. of lane markings; Recognition of the vehicle driving pattern in relation to the road

Abstract

Provided is an image processing device in which a region targeted for edge extraction of a taken image is divided into a plurality of partial regions 11(1) to 11(7) for which threshold values for edge extraction different from each other are set, respectively. An edge extraction unit 5, which extracts edges from the region targeted for edge extraction, performs processing of extracting the edges in the partial regions 11(1) to 11(7) by using the threshold values set so as to correspond to the each of the partial regions 11(1) to 11(7).

Claims

1. An image processing device comprising an imaging device mounted on a vehicle and an electronic circuit unit including a processor,

wherein each frame of an image taken by the imaging device includes a first partial region and a second partial region respectively occupying two non-overlapping parts of the image, and with each of the first and second partial regions consisting of pixels arranged in longitudinal and cross directions in the image, and

wherein the processor is configured to provide:

a first threshold setting unit which sets a first threshold value for the first partial region, based on a characteristic of the first partial region;

a second threshold setting unit which sets the second threshold value for a second partial region, based on a characteristic of the second partial region;

a first edge extraction unit which extracts an edge from the first partial region by comparing a pixel value change in the in the first partial region with the first threshold value; and

a second edge extraction unit which extracts an edge from the second partial region by comparing a pixel value change in the second partial region with the second threshold value,

wherein the first threshold value setting unit updates the first threshold value determined based on a number of edges extracted by the first edge extraction unit, and

the second threshold setting unit updates the second threshold value determined based on a number of edges extracted by the second edge extraction unit,

wherein the image includes a vehicle traveling road surface and both the first and second partial regions are regions of the vehicle traveling road surface.

2. The image processing device according to claim 1, wherein the first threshold for the first partial region where an image of a portion which is at a relatively long distance from the imaging device in a real space is projected is smaller than the second threshold value for the second partial region where an image of a portion which is at a relatively short distance from the imaging device is projected.

9. The image processing device according to claim 1, wherein the updating based on the number of edges of at least one of the first and second threshold values is performed only for the respective partial region with the respective threshold value or less.

12. The image processing device according to claim 1, wherein the first and second partial regions are arranged horizontally to each other.

3. An image processing device comprising an imaging device mounted on a vehicle and an electronic circuit unit including a processor,

wherein each frame of an image taken by the imaging device includes a first partial region and a second partial region respectively occupying two non-overlapping parts of the image, and with each of the first and second partial regions consisting of pixels arranged in longitudinal and cross directions in the image, and

wherein the processor is configured to provide:

a first threshold setting unit which sets a first threshold value for the first partial region, based on a characteristic of the first partial region;

a second threshold setting unit which sets the second threshold value for a second partial region, based on a characteristic of the second partial region;

a first edge extraction unit which extracts an edge from the first partial region by comparing a pixel value change in the in the first partial region with the first threshold value; and

a second edge extraction unit which extracts an edge from the second partial region by comparing a pixel value change in the second partial region with the second threshold value,

wherein the image includes a vehicle traveling road surface and both the first and second partial regions are regions of the vehicle traveling road surface, and

wherein the processor is further configured to provide;

a lane mark recognition unit configured to recognize an image of lane marks on the vehicle traveling road surface by using the edges extracted by the edge extraction unit corresponding to the region targeted for edge extraction including an image of the vehicle traveling road surface, wherein

the first threshold setting unit updates the first threshold value for the first partial region, in which at least the image of the lane marks is likely to be shown, determined based on a number of edges extracted by the first edge extraction unit in a local region set in the first partial region concerned so as to show an image of a road surface between the right and left lane marks of the vehicle traveling road surface, and the second threshold setting unit updates the second threshold value for the second partial region, in which at least the image of the lane marks is likely to be shown, determined based on a number of edges extracted by the second edge extraction unit in a local region set in the second partial region concerned so as to show and image of a road surface between the right and left lane marks of the vehicle traveling road surface.

5. The image processing device according to claim 3, wherein at least one of the first and second threshold setting units is configured to estimate locations of the lane marks in a frame of another image from the imaging device based on positions in the image of the lane marks ahead recognized by the lane mark recognition unit before updating at least one of the first and second threshold values and to set the local region based on the estimation result.

7. The image processing device according to claim 3, wherein the first threshold for the first partial region where an image of a portion which is at a relatively long distance from the imaging device in a real space is projected is smaller than the second threshold value for the second partial region where an image of a portion which is at a relatively short distance from the imaging device is projected.

10. The image processing device according to claim 3, wherein the updating based on the number of edges of at least one of the first and second threshold values is performed only for the respective partial region with the respective threshold value or less.

13. The image processing device according to claim 3, wherein the first and second partial regions are arranged horizontally to each other.

4. An image processing device comprising an imaging device mounted on a vehicle and an electronic circuit unit including a processor,

wherein each frame of an image taken by the imaging device includes a first partial region and a second partial region respectively occupying two non-overlapping parts of the image, and with each of the first and second partial regions consisting of pixels arranged in longitudinal and cross directions in the image, and

wherein the processor is configured to provide:

a first threshold setting unit which sets a first threshold value for the first partial region, based on a characteristic of the first partial region;

a second threshold setting unit which sets a second threshold value for the second partial region, based on a characteristic of the second partial region;

a first edge extraction unit which extracts an edge from the first partial region by comparing a pixel value change in the in the first partial region with the first threshold value; and

a second edge extraction unit which extracts an edge from the second partial region by comparing a pixel value change in the second partial region with the second threshold value,

wherein the image includes a vehicle traveling road surface and both the first and second partial regions are regions of the vehicle traveling road surface, and

wherein the processor is further configured to provide;

a lane mark recognition unit configured to recognize an image of lane marks on the vehicle traveling road surface by using the edges extracted by the edge extraction unit corresponding to the region targeted for edge extraction including an image of the vehicle traveling road surface, wherein

the first threshold setting unit updates the first threshold value for the first partial region, in which at least the image of the lane marks is likely to be shown, determined based on a number of edges extracted by the first edge extraction unit in a local region set in the first partial region concerned so as to show the image of the lane mark, and

the second threshold setting unit updates the second threshold value for the second partial region, in which at least the image of the lane marks is likely to be shown, determined based on a number of edges extracted by the second edge extraction unit in a local region set in the second partial region concerned so as to show the image of the lane mark.

6. The image processing device according to claim 4, wherein at least one of the first and second threshold setting units is configured to estimate locations of the lane marks in a frame of another image from the imaging device based on positions in the image of the lane marks ahead recognized by the lane mark recognition unit before updating at least one of the first and second threshold values and to set the local region based on the estimation result.

8. The image processing device according to claim 4, wherein the first threshold for the first partial region where an image of a portion which is at a relatively long distance from the imaging device in a real space is projected is smaller than the second threshold value for the second partial region where an image of a portion which is at a relatively short distance from the imaging device is projected.

11. The image processing device according to claim 4, wherein the updating based on the number of edges of at least one of the first and second threshold values is performed only for the respective partial region with the respective threshold value or less.

14. The image processing device according to claim 4, wherein the first and second partial regions are arranged horizontally to each other.