FFT amplitude spectrum

To detect the forged parts in a single image with copy-move attack, an autocorrelation detection method based on phase and amplitude spectrum of FFT is proposed.

针对一类单幅图像的复制遮盖篡改，提出一种基于快速傅立叶变换相位和幅度的自相关检测算法对篡改部位进行检测。

Comparing with the FFT and the amplitude measure arithmetic, the novel method can avoid the spectrum leakage and fence effect in ideal extent and improve the precision of harmonics measurement.

与FFT和幅值检测法相比，该方法能消除fft算法的频谱泄露，提高了谐波检测的精度，且适用于含有非整数次谐波的信号。

First of all, starting with the estimate of signal parameter (e. g. amplitude, frequency and phasic), it makes a research in algorithms of direct, subdivide the spectrum, high-precision FFT and so on.

首先，本文从信号参数(幅度、频率、相位)估计入手，研究了直接法、细化频谱法和高精度FFT法等算法。