基于链码和快速傅里叶变换的轮廓描绘方法

A contour description method based on chain code and fast Fourier transform

将八方向链码和快速傅里叶变换(FFT)相结合,提出一种新的形状轮廓描述方法。通过链码按顺序搜索物体边界,根据链码值的投影变换与轮廓的关系构造出轮廓的链码函数,对链码函数进行快速FFT,并对傅里叶描述符进行优化,提出了新的傅里叶不变因子描述符(FCFD)。实验结果表明,本文提出FCFD具有旋转、尺度和平移(RSS)不变性和初始点无关性,并且降低了运算量,有效提高了数据处理速率。

A new shape contour description method based on eight direction chain code and fast Fourier transform （FFT） is proposed. Firstly, the chain code tracks the shape boundary sequentially according to the relationship between contour and chain-code projection-transform value. A constructed chain-code function of contour is transformed using FFT. After optimization, then a new Fourier constant factor de- scriptor （FCFD） is proposed. The descriptor is independent of the initial point and has rotation, scale shift and （RSS） invariant properties. The results of experiments show that our shape contour description method has the RSS proerty and is non-correlative with the initual state. It reduces the computation and improves the efficiency of data processing effectively.