管理音訊輸入的問題

學習如何管理因音訊輸入品質而導致語音辨識準確度的問題。

重要 API：語音識別器、識別品質下降、語音辨識音頻問題。

評估音訊輸入品質

當語音辨識啟動時，利用語音辨識器的 「RecognitionQualityDegrading」 事件判斷是否有一個或多個音訊問題可能干擾語音輸入。 事件參數（SpeechRecognitionQualityDegradingEventArgs）提供了 問題 屬性，描述音訊輸入時偵測到的問題。

背景噪音過多、麥克風靜音，以及喇叭音量或速度可能會影響辨識。

在這裡，我們設定語音辨識器，開始聆聽 RecognitionQualityDegrading 事件。

private async void WeatherSearch_Click(object sender, RoutedEventArgs e)
{
    // Create an instance of SpeechRecognizer.
    var speechRecognizer = new Windows.Media.SpeechRecognition.SpeechRecognizer();

    // Listen for audio input issues.
    speechRecognizer.RecognitionQualityDegrading += speechRecognizer_RecognitionQualityDegrading;

    // Add a web search grammar to the recognizer.
    var webSearchGrammar = new Windows.Media.SpeechRecognition.SpeechRecognitionTopicConstraint(Windows.Media.SpeechRecognition.SpeechRecognitionScenario.WebSearch, "webSearch");


    speechRecognizer.UIOptions.AudiblePrompt = "Say what you want to search for...";
    speechRecognizer.UIOptions.ExampleText = "Ex. 'weather for London'";
    speechRecognizer.Constraints.Add(webSearchGrammar);

    // Compile the constraint.
    await speechRecognizer.CompileConstraintsAsync();

    // Start recognition.
    Windows.Media.SpeechRecognition.SpeechRecognitionResult speechRecognitionResult = await speechRecognizer.RecognizeWithUIAsync();
    //await speechRecognizer.RecognizeWithUIAsync();

    // Do something with the recognition result.
    var messageDialog = new Windows.UI.Popups.MessageDialog(speechRecognitionResult.Text, "Text spoken");
    await messageDialog.ShowAsync();
}

管理語音辨識體驗

利用 問題 屬性提供的描述，幫助使用者改善辨識條件。

在這裡，我們建立了一個處理 RecognitionQualityDegrading 事件的處理器，用來檢查音量是否偏低。 接著我們會用 SpeechSynthesizer 物件建議使用者嘗試大聲說話。

private async void speechRecognizer_RecognitionQualityDegrading(
    Windows.Media.SpeechRecognition.SpeechRecognizer sender,
    Windows.Media.SpeechRecognition.SpeechRecognitionQualityDegradingEventArgs args)
{
    // Create an instance of a speech synthesis engine (voice).
    var speechSynthesizer =
        new Windows.Media.SpeechSynthesis.SpeechSynthesizer();

    // If input speech is too quiet, prompt the user to speak louder.
    if (args.Problem == Windows.Media.SpeechRecognition.SpeechRecognitionAudioProblem.TooQuiet)
    {
        // Generate the audio stream from plain text.
        Windows.Media.SpeechSynthesis.SpeechSynthesisStream stream;
        try
        {
            stream = await speechSynthesizer.SynthesizeTextToStreamAsync("Try speaking louder");
            stream.Seek(0);
        }
        catch (Exception)
        {
            stream = null;
        }

        // Send the stream to the MediaElement declared in XAML.
        await CoreApplication.MainView.CoreWindow.Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.High, () =>
        {
            this.media.SetSource(stream, stream.ContentType);
        });
    }
}

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範例

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