Journal of South China University of Technology(Natural Science Edition) ›› 2012, Vol. 40 ›› Issue (4): 23-29.

• Computer Science & Technology • Previous Articles     Next Articles

Accurate and Fast Harmonic Transform of Polar Coordinates

Wo Yan  Xu Jiao   

  1. School of Computer Science and Engineering,South China University of Technology,Guangzhou 510006,Guangdong,China
  • Received:2011-10-28 Revised:2012-02-05 Online:2012-04-25 Published:2012-03-01
  • Contact: 沃焱(1975-) ，女，博士，副教授，主要从事多媒体应用技术研究． E-mail:woyan@scut.edu.cn
  • About author:沃焱(1975-) ，女，博士，副教授，主要从事多媒体应用技术研究．
  • Supported by:

    NSFC － 广东省联合基金资助项目( U1035004) ; 国家自然科学基金青年科学基金资助项目( 61003270) ; 国家自然科学基金面上项目( 61070090) ; 广东省工业攻关科技计划项目( 2009B030803004) ; 广东省重大科技专项( 2010A080402005) ;广东省自然科学基金博士启动项目( 10452840301004638) ; 华南理工大学中央高校基本科研业务费专项资金重点项目( 2012ZZ0066)

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Abstract:

This paper deals with the extension of the computation method of Zernike moments in polar coordinates to the computation of PHT moments in Cartesian coordinates. In the investigation,polar coordinates are designed and modulated for the computation of PHT moments,which can eliminate the geometric error and the integral approximate error of the computation in Cartesian coordinates. And,during the calculation of the kernel coefficients of PHT,the symmetry and the inquiry table of trigonometric function are used to reduce the computational complexity. Thus,the computation is accelerated and the iterative cumulative error is eliminated. The proposed fast PHT algorithm based on polar coordinates is finally verified by experiments and is compared with the existing one based on Cartesian coordinates. Experimental results show that the proposed algorithm is superior to the PHT algorithm based on Cartesian coordinates in terms of reconstruction accuracy,rotation scale invariance and calculation speed.

Key words: polar coordinates, harmonic transform, orthogonal moment, geometric invariant