Method for detecting symmetry axis of plane figure object

A technology of plane graphics and detection methods, applied in instruments, character and pattern recognition, computer parts and other directions, can solve the problem of inability to accurately detect the symmetry axis, and achieve the effect of reducing workload, strong robustness, and improving work efficiency

Inactive Publication Date: 2014-02-05
CHINA UNIV OF MINING & TECH (BEIJING)
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Problems solved by technology

[0033] In order to overcome the deficiency that the above-mentioned prior art cannot accurately detect the symmetry axes of locally symmetrical and quasi-symmetric graphic objects, the present invention provides a method for detecting the symmetric axis of a planar graphic object, which can accurately detect locally symmetrical or quasi-symmetrical graphic objects. The axis of symmetry of the quasi-symmetric plane graphics object

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  • Method for detecting symmetry axis of plane figure object
  • Method for detecting symmetry axis of plane figure object
  • Method for detecting symmetry axis of plane figure object

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Embodiment Construction

[0055] The present invention will be described in further detail below in conjunction with the accompanying drawings.

[0056] The detection method embodiment of the present invention in (k, b) space:

[0057] The concrete steps of this method are as follows:

[0058] (1) Suppose P is a plane graphics object, L: y=kx+b is a straight line in the plane, and the symmetry axis of P is roughly positioned as a straight line y=k by using the method of moment of inertia, least square method or principal component analysis 0 x+b 0 , determine the search area of ​​the corresponding point of the symmetry axis of P in the (k, b) space to include (k 0 , b 0 ) area Ω;

[0059] (2) Find the function value of the function C(k,b) at each point in the area Ω, where C(k,b)=Card(SSI(P,L,δ)), SSI(P,L, δ)=P s ∩P s ', P s is a shell of thickness δ at P, P s is the set of all points whose distance from at least one point on the boundary in P is not greater than δ, P s ' means P s Regarding...

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Abstract

The invention relates to the technical field of digital image processing and mode recognition, in particular to a method for detecting the symmetry axis of a plane figure object. The search process of the method can be conducted in space (k,b) or space (alpha, b) or space (alpha, b'), a search area including points corresponding to the symmetry axis is determined in the search space, then, an area function value of the intersection of a shell, with the thickness delta, of the plane figure object and a symmetrical figure is determined, the shell and the symmetrical figure are symmetrical about a straight line corresponding to all the points in the search space, maximal value points or a maximum value point of an area function in the search area is determined, straight lines corresponding to the maximal value points is used as an alternative line for the symmetry axis, finally, one or more straight lines are determined as the symmetry axes, and if the symmetry axis exists and is unique, the straight line corresponding to the maximum point is the symmetry axis of the plane figure object. According to the method, the symmetry axis of the partially-symmetrical plane figure object or the quasi-symmetrical plane figure object can be accurately detected.

Description

technical field [0001] The invention relates to the technical fields of digital image processing and pattern recognition, in particular to a method for detecting the symmetry axis of a plane graphic object. Background technique [0002] Symmetry is a common shape feature of objects in nature and human society. In the field of artificial vision, especially target recognition, the recognition of the symmetry axis of a plane figure is usually the basis for coordinate axis recalibration and object recognition. In the fields of vehicle and building recognition, face recognition, fingerprint recognition, seal recognition, brain CT image analysis and other fields, symmetry axis detection is a necessary basic link. [0003] The symmetry of plane graphic objects can be divided into the following three situations: [0004] 1. Strict symmetry: Let P={(x i ,y i )|i∈[1, N]} is a plane graphic object, and L is a straight line in the same plane. like aa′⊥L, and |ao|=|oa′|, where o...

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Application Information

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Patent Type & AuthorityApplications(China)
IPC IPC(8): G06K9/46
Inventor孙继平洪亮
OwnerCHINA UNIV OF MINING & TECH (BEIJING)