Method for determining orientation of contour line segment in local area and for determining straight line and corner
First Claim
1. An apparatus for determining an orientation of a local line segment in a contour in a local area of a binary contour image, comprising:
- contour image information holding means for holding information indicating at least coordinates of contour points of the binary contour image;
pixel number counting means for obtaining the number of pixels of the contour points existing in each of a plurality of orientations around a pixel on the contour point in the local area; and
local line segment orientation determining means for obtaining an orientation, in which the number of pixels of the contour point located in the orientation is greater than a predetermined number, as an orientation in which a local line segment exists.
0 Assignments
0 Petitions
Accused Products
Abstract
A method for determining an orientation of a line segment in a contour in a local area of a binary contour image. The number of pixels having a predetermined value and located in each orientation in the local area, is obtained, and it is determined that a line segment exists in an orientation in which the number of pixels is large. Further, when it is determined that the number of pixels located in each of a plurality of orientations and having a predetermined value, is greater than a sum of the numbers of pixels in orientations adjacent to said each orientation on both sides thereof, it is determined that a line segment exists in said each orientation. Two orientations in which large numbers of pixels are located are detected, and it is determined whether the point is a constituent of a line segment, a line segment of the sub-straight-line form, or a near-corner point, depending on angles made by the two orientations is equal to 180°, or a difference of the angles made by the two orientations from 180°. Contiguously arrayed pixels in the same orientation are detected as a line segment. A position and an orientation are obtained from points near a corner, and representative values of the positions and orientations of contiguously arrayed near-corner points are determined. (FIG. 3)
-
Citations
9 Claims
-
1. An apparatus for determining an orientation of a local line segment in a contour in a local area of a binary contour image, comprising:
-
contour image information holding means for holding information indicating at least coordinates of contour points of the binary contour image; pixel number counting means for obtaining the number of pixels of the contour points existing in each of a plurality of orientations around a pixel on the contour point in the local area; and local line segment orientation determining means for obtaining an orientation, in which the number of pixels of the contour point located in the orientation is greater than a predetermined number, as an orientation in which a local line segment exists. - View Dependent Claims (2, 3)
-
-
4. A computer readable product storing at least one program, for determining an orientation of a local line segment in a contour in a local area of a binary contour image, where said at least one program, when executed by a processing unit, causes the processing unit and its associated hardware to carry out a process, the process comprising:
-
a first step of obtaining the numbers of pixels, each having a first predetermined value, located in a plurality of orientations around one of plural pixels located in the local area and having said first predetermined value; and a second step of determining that a local line segment exists in an orientation when the number of pixels located in the orientation is greater than a second predetermined value, and said number of pixels located in the orientation, which is obtained in the first step, is the largest.
-
-
5. A computer readable product storing at least one program, for determining an orientation of a local line segment in a contour in a local area of a binary contour image, where said at least one program, when executed by a processing unit, causes the processing unit and its associated hardware to carry out a process, the process comprising:
-
a first step of obtaining the numbers of pixels, each having a first predetermined value, located in a plurality of orientations around one of plural pixels located in the local area and having said first predetermined value; and a second step of determining that local line segments exist in two orientations when the numbers of pixels located in the two orientations are greater than a second predetermined value, and the numbers of pixels located in the two orientations, obtained in the first step, are the largest and the second largest, respectively.
-
-
6. A method for determining an orientation of a local line segment in a contour in a local area of a binary contour image, comprising:
-
a first step for obtaining the numbers of pixels each having a first predetermined value and located in a plurality of orientations around one of plural pixels located in the local area and having said first predetermined value; and a second step for determining that a local line segment exists in an orientation when the number of pixels located in the orientation is greater than a second predetermined value, and said number of pixels located in the orientation, which is obtained in the first step, is the largest.
-
-
7. An apparatus for determining an orientation of a local line segment in a contour in a local area of a binary contour image, comprising:
-
a contour image information holding unit holding information indicating at least coordinates of contour points of the binary contour image; a pixel number counter counting the number of pixels of the contour points existing in each of a plurality of orientations around a pixel on the contour point in the local area; and a local line segment orientation determining unit determining an orientation in which the number of pixels of the contour point located in the orientation is greater than a predetermined number, as an orientation in which a local line segment exists. - View Dependent Claims (8, 9)
-
Specification