IMAGE PROCESSING APPARATUS AND IMAGING APPARATUS USING THE SAME

• US 20130147948A1
• Filed: 07/27/2011
• Published: 06/13/2013
• Est. Priority Date: 09/30/2010
• Status: Abandoned Application

• Current Assignee: Hitachi Automotive Systems Limited (Hitachi, Ltd.)
• Original Assignee: Morihiko Sakano
• Inventors: Sakano, Morihiko, Shima, Takeshi, Muramatsu, Shoji, Monji, Tatsuhiko, Higuchi, Mirai
• Application Number:
  US13/818,625
• Publication Number:
  US 20130147948A1
• Time in Patent Office: Days
• US Class Current: 348/135
• CPC Class Codes: G01B 11/14 for measuring distance or clearance between spaced objects or spaced apertures G01B11/26 takes precedence; rangefinders G01C3/00
• CPC Class Codes: G06T 2207/30256 Lane; Road marking
• CPC Class Codes: G06T 2207/30261 Obstacle
• CPC Class Codes: G06T 7/85 Stereo camera calibration
• CPC Class Codes: H04N 13/128 Adjusting depth or disparity
• CPC Class Codes: H04N 13/246 Calibration of cameras
• CPC Class Codes: H04N 17/002 for television cameras
• CPC Class Codes: H04N 2013/0081 Depth or disparity estimation from stereoscopic image signals

Abstract

It is possible to provide an image processing apparatus capable of carrying out calibration easily and precisely without requiring a special facility and provide an imaging apparatus making use of the image processing apparatus. The imaging apparatus comprises at least two cameras 4a and 4b. The image processing apparatus or the image processing apparatus comprises a corresponding-area computing section 23 for finding a relation between areas on images taken by the cameras 4a and 4b; a coincidence-degree computing section 24 for finding a degree of coincidence of information obtained from corresponding areas on the images taken by the cameras 4a and 4b; and a camera-parameter computing section 25 for finding camera parameters on the basis of the coincidence degree computed by the coincidence-degree computing section 24.

Claims

1. An image processing apparatus comprising:

a correction-data reading section for reading pre-stored correction data to be used for correcting two images taken in such a way that their visual fields overlap each other and at least one of their positions, their angles and their zoom ratios are different from each other or for reading correction data computed by carrying out processing;

an image correcting section for correcting a taken image by making use of said correction data read by said correction-data reading section;

a corresponding-area computing section for computing corresponding areas selected from the inside of each of two images corrected by said image correcting section;

a coincidence-degree computing section for computing at least one of a degree of coincidence of image patterns extracted from said corresponding areas, a degree of coincidence of coordinates of said corresponding areas and a degree of coincidence of gaps between said corresponding areas;

a camera-parameter computing section for computing camera parameters on the basis of a coincidence degree computed by said coincidence-degree computing section; and

a correction-data storing section for storing said camera parameters computed by said camera-parameter computing section or correction data based on said camera parameters.

2. The image processing apparatus according to claim 1, wherein:

said camera parameters computed by said camera-parameter computing section are internal parameters, external parameters or distortion parameters;

said internal parameters including at least one of the focal length of an imaging device, the vertical-direction size of a pixel, the horizontal-direction size of a pixel, a vertical-direction scale factor, a horizontal-direction scale factor, an angle formed by the vertical and horizontal axes of said imaging device and the coordinates of an optical-axis center;

said external parameters including at least one of the rotation angle of said imaging device and the parallel translation of said imaging device; and

said distortion parameters being parameters used for correcting distortions of an image.

3. The image processing apparatus according to claim 1, wherein said camera-parameter computing section computes a set of edge points of a parallel pattern selected from the inside of each of two taken images as a corresponding area.

4. The image processing apparatus according to claim 3, wherein:

when computing a degree of coincidence of gaps of said corresponding areas, said coincidence-degree computing section computes said degree of coincidence by comparing at least one of computed values, pre-stored or pre-defined widths of parallel patterns and widths received from an external apparatus as the widths of parallel patterns; and

said computed values are each a value computed from at least one of the average of gaps between said corresponding areas, the minimum value among said gaps between said corresponding areas and the maximum value among said gaps between said corresponding areas.

5. The image processing apparatus according to claim 1, wherein:

said coincidence-degree computing section computes a degree of coincidence of said corresponding areas on the basis of characteristic quantities obtained from an image; and

said characteristic quantities are at least one of luminance values inside said corresponding area, brightness gradients, luminance-change directions, color information, color gradients, color gradient directions, a histogram of the luminance, a histogram of the brightness gradient, a histogram of the color gradient, a histogram of the brightness gradient direction and a histogram of the color gradient directions.

6. The image processing apparatus according to claim 1, wherein said correction data is camera parameters stored in advance or a transformation table showing pre-correction and post-correction relations computed on the basis of said camera parameters.

7. The image processing apparatus according to claim 6, further comprising a correction-data storing section for storing said camera parameters computed by said camera-parameter computing section or said transformation table as correction data.

8. The image processing apparatus according to claim 1, wherein said image correcting section makes use of camera parameters of a specific one of two imaging devices as correction data in order to correct an image taken by the other one of said two imaging devices.

9. The image processing apparatus according to claim 3, wherein:

said corresponding-area computing section computes an area including a pattern, which is detected from a taken image, as said corresponding area,

said pattern being the pattern of at least one of a pedestrian, a vehicle, a road surface, a road-surface sign, a construction and a structure.

10. The image processing apparatus according to claim 3, wherein:

said corresponding-area computing section computes an area including a pattern, which is detected from a taken image, as said corresponding area,

said pattern being the pattern of at least one of a boundary line between a floor and a wall surface inside a house, a boundary line between a ceiling and a wall surface inside a house or a window frame inside a house.

11. The image processing apparatus according to claim 1, wherein:

a coincidence degree computed by said coincidence-degree computing section as said degree of coincidence is used as a basis for carrying out determination as to whether or not an abnormality has been generated in an imaging device or whether or not said acquired correction data is correct; and

on the basis of a result of said determination, a termination signal for stopping the operation of said imaging device is output or a warning signal used for issuing a warning to the user is output.

12. The image processing apparatus according to claim 1, wherein said corresponding-area computing section computes a plurality of corresponding areas on one taken image.

13. The image processing apparatus according to claim 12, wherein said corresponding areas have different distances from an imaging device.

14. The image processing apparatus according to claim 1, wherein images taken by an imaging device are images taken with timings different from each other.

15. The image processing apparatus according to claim 1, comprising means for copying an image taken by an imaging device.

16. The image processing apparatus according to claim 1, comprising:

a disparity computing section for computing disparity information from two images corrected by said image correcting section; and

an image recognizing section for detecting a body of at least one of a pedestrian, a vehicle, a construction and a structure, a road surface and a road-surface sign on the basis of said disparity information.

17. The image processing apparatus according to claim 16, wherein said corresponding-area computing section computes an area, which includes said body detected by said image recognizing section, as said corresponding area.

18. An imaging apparatus having:

two imaging devices for taking images; and

processing means for carrying out image processing on images taken by said imaging devices,

wherein said processing means comprises;

a correction-data reading section for reading pre-stored correction data used for correcting two images taken by said two imaging devices;

an image correcting section for correcting a taken image by making use of said correction data read by said correction-data reading section;

a corresponding-area computing section for computing corresponding areas selected from the inside of each of two images corrected by said image correcting section;

a coincidence-degree computing section for computing at least one of a degree of coincidence of image patterns extracted from said corresponding areas, a degree of coincidence of coordinates of said corresponding areas and a degree of coincidence of gaps between said corresponding areas; and

a camera-parameter computing section for computing camera parameters on the basis of a coincidence degree computed by said coincidence-degree computing section.

19. The imaging apparatus according to claim 18, comprising storage means for storing said correction data.

20. The imaging apparatus according to claim 18, comprising program storing means for storing a calibration program to be executed for calibrating said imaging devices,

wherein said processing means carries out functions of said correction-data reading section, said image correcting section, said corresponding-area computing section, said coincidence-degree computing section and said camera-parameter computing section on the basis of said calibration program, which has been stored in said program storing means, when a signal for turning on a power supply is received.