快速傅立叶变换的C＃

Question

可能重复：
Fast fourier transform in c#

我要寻找或麦克风的音频数据线进行实时FFT（快速傅立叶变换）的例子在C＃中。我的目标是实时确定音频数据中是否存在特定音符。任何例子赞赏。

Answer 1

AForge.NET是一个具有快速傅里叶变换支持的开源库。
ExocortexDSP也是另一种选择。

ExocortexDSP例子是这个样子：

Exocortex.DSP.ComplexF[] complexData = new Exocortex.DSP.ComplexF[512]; 
    for (int i = 0; i < 512; ++i) 
    { 
     // Fill the complex data 
     complexData[i].Re = 1; // Add your real part here 
     complexData[i].Im = 2; // Add your imaginary part here 
    } 

    // FFT the time domain data to get frequency domain data 
    Exocortex.DSP.Fourier.FFT(complexData, Exocortex.DSP.FourierDirection.Forward); 

    float[] mag_dat_buffer = new float[complexData.Length]; 
    // Loop through FFT'ed data and do something with it 
    for (int i = 0; i < complexData.Length; ++i) 
    { 
     // Calculate magnitude or do something with the new complex data 
     mag_data_buffer[i] = ImaginaryNumberMagnitude(complexData[i].Im, complexData[i].Re); 
    }