SpeechRecognition reconnaît le bruit de fond comme discours

J'utilise le SpeechSrecognengine code> dans mon programme. Le problème est qu'il reconnaît le bruit de fond comme point de parole.

Par exemple, si vous appuyez sur les doigts, appuyez sur la table ou déplacez ma chaise, il choisit comme un discours. P>

Pourquoi dans la dose du monde Il reconnaît le bruit de fond comme discours. P>

me frapper ma dose de doigts ne sonne pas la même chose que moi disant "Notepad" !!! P>

Voici le code P>

using System;
using System.Threading;
using System.Speech;
using System.Speech.Synthesis;
using System.Speech.Recognition;

namespace SpeachTest
{
    public class MainClass
    {
        static void Main()
        {
        MainClass main = new MainClass(); 
        SpeechRecognitionEngine sre = new SpeechRecognitionEngine(new System.Globalization.CultureInfo("en-US"));
            Choices choiceList = new Choices();
            choiceList.Add(new string[]{"Open", "Close", "Then", "Volume", "Up", "Firefox", "Notepad", "Steam","turn", "the", "now" } );

            GrammarBuilder builder = new GrammarBuilder();
            builder.Append(choiceList);
            Grammar grammar = new Grammar(new GrammarBuilder(builder,0, 10) );

            sre.SpeechRecognized += main.sreRecognizedEvent;
            sre.SpeechDetected += main.sreDetectEvent;
            sre.SpeechRecognitionRejected += main.sreRejectEvent;
            sre.RecognizeCompleted += main.sreCompleteEvent;

            sre.InitialSilenceTimeout = TimeSpan.FromSeconds(0);
            sre.BabbleTimeout = TimeSpan.FromSeconds(0);
            sre.EndSilenceTimeout = TimeSpan.FromSeconds(0);
            sre.EndSilenceTimeoutAmbiguous = TimeSpan.FromSeconds(0);


            sre.SetInputToDefaultAudioDevice();
            sre.LoadGrammar(grammar);

            while(true){
            sre.Recognize();
            }
        }


        void sreRecognizedEvent(Object sender, SpeechRecognizedEventArgs e){
        Console.Write("Reconized ~ " + e.Result.Text + " ~ with confidence " + e.Result.Confidence);
        Console.WriteLine();
        }


        void sreDetectEvent(Object sender, SpeechDetectedEventArgs e){
        Console.WriteLine("Detected some type of input");
        }

        void sreRejectEvent(Object sender,  SpeechRecognitionRejectedEventArgs e){
        Console.WriteLine("Rejected Input ~ " + e.Result.Text) ;
        }

        void sreCompleteEvent(Object sender, System.Speech.Recognition.RecognizeCompletedEventArgs e){
        Console.WriteLine("Completed Recongnization");
        }
}

}