CAJ | 학술논문

为了描述形状由全局信息到局部变化的层次信息，提出一种有效的形状签名，即多级夹角函数。多级夹角函数具有内在的旋转、平移和缩放不变性。对轮廓上每一点，其多级夹角函数通过轮廓的非等弧长分割所得的成对线段计算得到。然后利用多级夹角函数推导出傅里叶描述子，以进行高效的形状检索。使用标准的性能评价方法对所提出的描述子在3个形状图像库上进行了测试，包括 MPEG-7图像库、Kimia-99图像库和 Swedish 树叶图像库。形状检索实验结果表明，基于多级夹角函数的傅里叶描述子优于已有的傅里叶描述子，且具有较低的计算复杂度。与其他类型的形状描述方法相比，所提出的描述子在相同查全率时具有最高的查准率，证明了该描述子的有效性。
위료묘술형상유전국신식도국부변화적층차신식，제출일충유효적형상첨명，즉다급협각함수。다급협각함수구유내재적선전、평이화축방불변성。대륜곽상매일점，기다급협각함수통과륜곽적비등호장분할소득적성대선단계산득도。연후이용다급협각함수추도출부리협묘술자，이진행고효적형상검색。사용표준적성능평개방법대소제출적묘술자재3개형상도상고상진행료측시，포괄 MPEG-7도상고、Kimia-99도상고화 Swedish 수협도상고。형상검색실험결과표명，기우다급협각함수적부리협묘술자우우이유적부리협묘술자，차구유교저적계산복잡도。여기타류형적형상묘술방법상비，소제출적묘술자재상동사전솔시구유최고적사준솔，증명료해묘술자적유효성。
An effective shape signature namely multi-level included angle functions MIAFs is proposed to describe the hierarchy information ranging from global information to local variations of shape.Invariance to rotation translation and scaling are the intrinsic properties of the MIAFs.For each contour point the multi-level included angles are obtained based on the paired line segments derived from unequal-arc-length partitions of contour.And a Fourier descriptor derived from multi-level included angle functions MIAFD is presented for efficient shape retrieval.The proposed descriptor is evaluated with the standard performance evaluation method on three shape image databases the MPEG-7 database the Kimia-99 database and the Swedish leaf database. The experimental results of shape retrieval indicate that the MIAFD outperforms the existing Fourier descriptors and has low computational complexity.And the comparison of the MIAFD with other shape description methods also shows that the proposed descriptor has the highest precision at the same recall value which verifies its effectiveness.