Abstract
Description or discrimination of boundary curves is an important problem in image processing and pattern recognition. Fourier descriptors have been shown to be useful in this respect. The periodic function which is obtained by tracing the closed contour can be expressed in a Fourier series. These descriptors have been used for shape discrimination noting that the coefficients are invariant to size, angular orientation, position, and starting conditions. In this paper, a critical review is given of two kinds of Fourier descriptors. Some properties of the Fourier descriptors are given and algorithms for computing the Fourier descriptors of the polygonal curve are proposed. We can apply them to an improved shaped-based interpolation method for grey-level images. The new method uses polygon to approximate the object shape and performs the interpolation using polygon vertices as references. This process is not only able to achieve a better interpolation but also its application is not limited to binary images.