Land mark, land mark detecting apparatus, land mark detection method and computer program of the same

• US 20050117781A1
• Filed: 10/12/2004
• Published: 06/02/2005
• Est. Priority Date: 12/01/2003
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company), Infineon Technologies AG
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Aoyama, Chiaki
• Granted Patent: US 7,403,669 B2
• Time in Patent Office: Days
• US Class Current: 382/103
• CPC Class Codes: G06T 7/73 using feature-based methods
• CPC Class Codes: G06V 10/48 by mapping characteristic values of the pattern into a parameter space, e.g. Hough transformation

Abstract

The present invention provides a land mark detecting apparatus simultaneously used with a land mark comprising plural mark primitives. The land mark detecting apparatus comprises a set of cameras and a land mark detector which includes an image signal interface unit, a pre-processing unit, a straight line detector to and a mark specifying unit.

Claims

1. A land mark comprising plural mark primitives which have rectangular shapes and are aligned in a reference line to which all of said rectangular shapes have parallel sides, wherein a first mark primitive has longer sides parallel to said reference line than a second and a third mark primitives which are placed in both sides of said first mark primitive along said reference line, respectively.

2. A land mark according to claim 1, wherein said second and third mark primitives have different lengths of sides which are parallel to said reference line.

3. A land mark according to claim 1, wherein a distance from the left end of said first mark primitive to the left end of said second mark primitive substantially equals to the right end of said first mark primitive to the right end of said third mark primitive.

4. A land mark according to claim 1, wherein said mark primitives are made of a recursive reflective material.

5. A land mark detecting apparatus simultaneously used with a land mark defined in claim 1, comprising a set of cameras and a land mark detector which includes

an image signal interface unit to receive image signals from said set of cameras and to generate a video image picture from said image signals,

a pre-processing unit to determine candidate regions for said mark primitives in said video image picture wherein said candidate regions are remarked by any one of differences of the color and brightness of the image,

a straight line detector to detect straight line segments of said candidate regions in said video image picture,

a mark specifying unit to specify positions of said mark primitives in said land mark by extracting from said candidate regions for said mark primitives on a basis of information of elemental dimensions and relative dimensional ratios which are predetermined for said land mark and information of presence ratio of said region exiting on said straight line segments.

6. A pre-processing unit according to claim 5, wherein said straight line detector includes an edge image generator which generates an edge image picture from said video image picture and a Hough transformation processor which extracts straight lines from edge images in said edge image picture by Hough transforming said edge images.

7. A mark specifying unit according to claim 5 further including a three-dimensional land mark position determining unit that computes three-dimensional position of said land mark on a basis of said candidate regions for said mark primitives and dimensional land mark data stored in a mark data storage.

8. A mark specifying unit according to claim 7, wherein three-dimensional land mark position determining unit further uses edges of mark primitive of which edges are determined by differentiated light intensities of said video image pictures.

9. A land mark detecting method, by which a land mark comprising plural mark primitives which have rectangular shapes and are aligned in a reference line to which all of said rectangular shapes have parallel sides is detected, comprising steps of;

receiving video images taken by plural cameras,

pre-processing for determining candidate regions for said mark primitives in said video image picture wherein said candidate regions are remarked by any one of differences of color and brightness of image,

generating an edge image picture by detecting edges of all of said candidate region,

carrying out a Hough transformation process of said edge image picture by which straight lines are detected from edge images in said edge image picture,

specifying positions of said land primitives in said land mark by extracting from said candidate regions for said mark primitives on a basis of information of elemental mark dimensions and relative dimensional ratios which are predetermined for said land mark and information of presence ratio of said region exiting on said straight line segments, and

computing a three-dimensional land mark on a basis of said candidate regions for said mark primitives and dimensional land mark data stored in a mark data storage.

10. A computer program of landmark detection, by which a land mark comprising plural mark primitives which have rectangular shapes and are aligned in a reference line to which all of said rectangular shapes have parallel sides is detected under cooperation with a computer system which comprises at least one computer hardware, enabling said computer system to execute steps of;

controlling receipt of video images taken by plural cameras,

pre-processing for determining candidate regions for said mark primitives in said vide image picture wherein said candidate regions are remarked by any one of differences of color of image and brightness of image,

generating an edge image picture by detecting edges of all of said candidate region,

carrying out a Hough transformation process of said edge image picture by which straight lines are detected from edge images in said edge image picture,

specifying positions of said land primitives in said land mark by extracting from said candidate regions for said mark primitives on a basis of information of elemental mark dimensions and relative dimensional ratios which are predetermined for said land mark and information of presence ratio of said region exiting on said straight line segments, and

computing a three-dimensional land mark on a basis of said candidate regions for said mark primitives and dimensional land mark data stored in a mark data storage.