C#中的自相关 [英] Auto Correlation in C#

问题描述

我正在尝试减少系统播放的.wav文件输出中的噪音.根据Jeff Morton的文章(带有频谱图的声控录音机，我可以得到频谱图和频域显示，但是，我意识到输出中的音频太多，从而使显示模糊，从各种文章中，我了解到可以使用自相关来降低噪声.无法理解如何根据Jeff Morton的代码在C#中实现它.
谁能帮我吗?
GeoNav

Hi,
I am trying to reduce the noise in a .wav file output while it is played by the system. Based on the Article by Jeff Morton ( Sound Activated Recorder with Spectrogram, I am able to get the spectrogram and Frequency Domain display. However, I realised that there is too much of audio in the output that blurs the display. From various articles, I understood that autocorrelation can be used to reduce the noise.But I am not able to understand how to implement it in C# in line with the code of Jeff Morton.
Can anyone help me please?
GeoNav

推荐答案

目前尚不清楚为什么要减少噪音.如果您想减少显示器上的模糊(我不认为您可以称其为模糊，但可能是由于Jeff的作品中所显示的频谱图看起来很模糊)，您可以减少频谱图上的点将接近的频率分组在一起，并显示一组的平均幅度作为横坐标值.在他的文章页面上询问Jeff以获取更多详细信息，请参阅页面末尾的评论和讨论".

我认为您无法通过使用自相关方法来降低您感兴趣的噪声.这种方法的强大功能可以帮助检测隐藏的周期性信号(例如在其有节奏的基础上)，但是在没有音频的强烈失真的情况下，很难消除非线性失真或录制过程中其他缺陷所产生的技术性"噪声. .请参见 http://en.wikipedia.org/wiki/Auto-correlation [
有关噪声控制的其他方法，请参见 http://en.wikipedia.org/wiki/Noise_reduction [ ^ ]，http://en.wikipedia.org/wiki/Noise_control [ ^ ].

—SA

It is not clear why do you want to reduce the noise. If you want to reduce the blur on the display (I don''t think you can call it blur, but probably you mean a blurry look of the spectrogram as it is shown in Jeff''s work), you can reduce number of points on the spectrogram grouping close frequencies together and showing average amplitude for a group as abscissa value. Ask Jeff for more detail on his Article''s page, see "Comments and Discussions" at the end of the page.

I don''t think you can reduce the noise in the sense your are interested in by using auto-correlation method. The power of this method could help to detect hidden periodic signal (such in a rhythmical base of it) but hardly could clean up a "technical" noise generated by non-linear distortions or other defects of the recording process without strong distortion of the audio. See http://en.wikipedia.org/wiki/Auto-correlation[^], pay attention for discreet autocorrelation for signal processing. If you need to estimate effective average pitch of the recorded instrument sound (which is required by digital instrument tuners) or detect musical beats in the uniform-tempo musical samples, it could help; in all other cases, when all such characteristics "flow" at fast pace, you will only mess up the audio.

For other methods of noise control, see http://en.wikipedia.org/wiki/Noise_reduction[^], http://en.wikipedia.org/wiki/Noise_control[^].

—SA

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