用途：数字图象处理算法的演示，包括： • 图象的DFT和逆DFT • 图象的FFT和逆FFT • 在图象中加入正弦噪声 • 图象的模板运算实现图象平滑和锐化 • 图象的直方图均衡化 • 图象的对比度拉伸 • 图象的中值滤波 • 图象灰度直方图的显示 • 若干频域滤波器 • 图象的镜像 • 图象的旋转（

This function generates normalized rayleigh samples based on Inverse DFT

Channel estimation techniques for OFDM systems based on a pilot arrangement are investigated. Channel estimation based on a comb type pilot arrangement is studied through different algorithms for both estimating the channel at pilot frequencies and i