介绍fft指纹增强算法，该源码测试可行。希望对大家有用。-Introduction fft fingerprint enhancement algorithm, the source test feasible. Hope useful for all of us.

通过傅里叶扩展计算的微分和积分函数，十分有用。-Descr iption The n-th order derivative or integral of a function defined in a given range [a,b] is calculated through Fourier series expansion, where n is any real number and not necessarily integer. The necessa