Recognition of Partially Occluded Polygon from Line Drawing
ZHANG GuiMei1,2, GAO ManTun1, SHEN YunWen1
1.Institute of Mechanical and Electrical Engineering, Northwestern Polytechnical University, Xi’an 710072 2.Key Laboratory of Nondestructive Test Ministry of Education, Nanchang Institute of Aeronautical Technology, Nanchang 330063
Abstract：The existing methods for recognizing the partially occluded polygon always carry out under the similarity transformation. A new method for recognition of partially occluded polygon under the affine transformation is proposed. First, a new local invariant under the affine transformation is given based on the invariants in computer vision. Next, on the basis of the local invariant, a new similarity function is established. Then a transform function is designed to normalize the similarity measure value between 0 and 1, so it is convenient to select the similarity measure threshold. Finally, a lost feature judgement function is constructed to judge whether each local featuer is lost, and similarity measure is calculated only using the local features that are not lost. By comparing the similarity measure with the threshold, the polygon objects can be recognized from a partially occluded line drawing. Noise and occlusion are considered in the construction of the similarity function and the lost feature judgement function. The experiment results show that the proposed algorithms are insensitive for noise and occlusion.
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2007, Vol. 20 
