Abstract: The convolution has widespread application in the digital signal processing and the image processing domain.This article gives a method of computing convolution integral based on the circle function of the symmetry descriptor.Using trapezoidal method，the authors first sample from the circle function，and then discretize the convolution integral.Using the fast Fournier transformation，the authors compute the discrete convolution and finally analyze the computation times and error.

Key words: symmetry descriptor, symmetry distance, convolution integral, FFT

摘要： 卷积在数字信号处理和图像处理领域有着广泛的应用。研究了基于圆周函数的对称描述符的卷积积分的计算问题。采用了梯形法对圆周函数取样，离散化卷积积分，并利用快速傅立叶变换计算离散卷积，最后进行复杂度分析和误差分析。

关键词: 对称描述符, 对称距离, 卷积, 快速傅立叶变换