麦克风阵列研究3 定向录音

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已于 2022-03-12 10:09:01 修改 · 3.3k 阅读

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于 2022-03-12 08:20:32 首次发布

本文介绍了作者通过调整配置文件实现定向录音优化的过程，针对ReSpeaker USB 4 Mic Array进行定向录音，尝试改善目标方向稳定性。作者参考GitHub上的建议，将sst模块设置为静态，并指定方向坐标。同时，修改界面以增强定向效果的可视化。尽管取得了一些进步，但作者发现定向录音效果仍不尽如人意，推测可能是因为4通道阵列的限制以及sst与ssl模块的差异造成。此外，作者还分享了如何播放和分析postfiltered.raw文件的方法，并提供了界面代码的改动，以显示sst的活动值变化。

上一篇文章实现了测向，也尝试了定向录音的效果。虽然定向录音是有效果的，但是好像目标方向不太稳定。

后来我找到如下文章，它说要在sst里把dynamic改为static，并且指定好方向坐标。Can I record the sound only in fixed direction? · Issue #158 · introlab/odas · GitHubhttps://github.com/introlab/odas/issues/158

于是，我就相应改了cfg文件，方向对应麦克风圆心正上方。

# Configuration file for ReSpeaker USB 4 Mic Array (ReSpeaker USB Mic Array v2.0)

version = "2.1";

# Raw

raw: 
{

    fS = 16000;
    hopSize = 128;
    nBits = 16;
    nChannels = 6; 

    # Input with raw signal from microphones
    interface: {
        type = "soundcard";
        card = 2;
        device = 0;
    }

}

# Mapping

mapping:
{

    map: (2, 3, 4, 5);

}

# General

general:
{
    
    epsilon = 1E-20;

    size: 
    {
        hopSize = 128;
        frameSize = 256;
    };
    
    samplerate:
    {
        mu = 16000;
        sigma2 = 0.01;
    };

    speedofsound:
    {
        mu = 343.0;
        sigma2 = 25.0;
    };

    mics = (

        # Microphone 2
        { 
            mu = ( -0.032, +0.000, +0.000 ); 
            sigma2 = ( +0.000, +0.000, +0.000, +0.000, +0.000, +0.000, +0.000, +0.000, +0.000 );
            direction = ( +0.000, +0.000, +1.000 );
            angle = ( 80.0, 100.0 );
        },

        # Microphone 3
        { 
            mu = ( +0.000, -0.032, +0.000 ); 
            sigma2 = ( +0.000, +0.000, +0.000, +0.000, +0.000, +0.000, +0.000, +0.000, +0.000 );
            direction = ( +0.000, +0.000, +1.000 );
            angle = ( 80.0, 100.0 );
        },

        # Microphone 4
        { 
            mu = ( +0.032, +0.000, +0.000 ); 
            sigma2 = ( +0.000, +0.000, +0.000, +0.000, +0.000, +0.000, +0.000, +0.000, +0.000 );
            direction = ( +0.000, +0.000, +1.000 );
            angle = ( 80.0, 100.0 );
        },

        # Microphone 5
        { 
            mu = ( +0.000, +0.032, +0.000 ); 
            sigma2 = ( +0.000, +0.000, +0.000, +0.000, +0.000, +0.000, +0.000, +0.000, +0.000 );
            direction = ( +0.000, +0.000, +1.000 );
            angle = ( 80.0, 100.0 );        
        }
        
    );

    # Spatial filter to include only a range of direction if required
    # (may be useful to remove false detections from the floor)
    spatialfilters = (

        {
            direction = ( +0.000, +0.000, +1.000 );
            angle = (80.0, 100.0);

        }    

    );

    nThetas = 181;
    gainMin = 0.25;

};

# Stationnary noise estimation

sne:
{
    
    b = 3;
    alphaS = 0.1;
    L = 150;
    delta = 3.0;
    alphaD = 0.1;

}

# Sound Source Localization

ssl:
{

    nPots = 4;
    nMatches = 10;
    probMin = 0.5;
    nRefinedLevels = 1;
    interpRate = 4;

    # Number of scans: level is the resolution of the sphere
    # and delta is the size of the maximum sliding window
    # (delta = -1 means the size is automatically comput

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