在用ＭＡＴＬＡＢ对心电信号去噪处理时得到的结果很差，下面是我的程序，请高手指点下，谢谢了！！
ecg1 = ReadMITdatafun('D:\data','103.hea','103.atr','103.dat',6500);
ecg2 = resample(ecg1,250,360);
ecg = ecg2';
ecg=ecg(1:4512);
subplot(221);plot(ecg);

title('原心电信号');
r=ecg+0.04*randn(size(ecg));
subplot(222);plot(r);
title('加入肌电干扰后信号');
n=0.04*randn(size(ecg));
subplot(224);plot(n);
axis([0 5000 -2 3]);
title('去除的肌电干扰信号');
[C,L]=wavedec(r,3,'coif4');
S3=appcoef(C,L,'coif4',3);
WT1=detcoef(C,L,1);
WT2=detcoef(C,L,2);
WT3=detcoef(C,L,3);




for i=1:2267
th1=0.04*sqrt(2*log(2267))/log(2);
    if WT1(i)<th1;
        WT11(i)=0;
    else
       if WT1(i)>0
            p=1;
        elseif WT1(i)<0
            p=-1;
        else p=0;
           end  
        WT11(i)=p*(abs(WT1(i))-th1);
    end
end
for i=1:1145
    th2=0.04*sqrt(2*log(1145))/log(2);
    if WT2(i)<th2;
        WT21(i)=0;
    else
       if WT2(i)>0
            p=1;
        elseif WT2(i)<0
            p=-1;
        else p=0;
           end  
        WT21(i)=p*(abs(WT2(i))-th2);
    end
end
for i=1:584
   th3=0.04*sqrt(2*log(584))/log(2); 
    if WT3(i)<th3;
        WT31(i)=0;
    else
       if WT3(i)>0
            p=1;
        elseif WT3(i)<0
            p=-1;
        else p=0;
           end  
        WT31(i)=p*(abs(WT3(i))-th3);
    end
end
C1=[S3,WT31,WT21,WT11];
x=waverec(C1,L,'coif4');
subplot(223);plot(x);
title('去除肌电干扰后信号');
norm(ecg-x)