读取MIT-BIH数据，制作数据集

       暑假实习搞了一段时间的深度的学习，公司老总让我把MIT-BIH的数据按着给的注释文件读出来，并且分类，为此我可是耗费了好长时间整理了这个程序供大家参考。闲话不多说，我交代下这个程序的作用：
                               1.把R波作为101点，向前取100点，向后取199个点，构成300点，作为一个心电周期（采样率为360HZ，所以300点完全可以保证一个心电周期）
                               2.按着数据名+第n个R波+疾病（N：正常，V：心律异常，O：其他）来命名
                               3.保存成txt格式，和无坐标轴的png格式。

代码如下：clc; clear all;
%这个程序可以一次性把48个数据都分类。
%------ SPECIFY DATA ------------------------------------------------------
PATH= 'S:\MIT'; % path, where data are saved下载下来的心电数据
d = dir('S:\MIT\*.dat');
a = dir('S:\MIT\*.atr');
v= dir('S:\MIT\*.hea');
l=2;%1为MLII通道，2为VI通道
for c=1:length(d)
HEADERFILE= v(c).name; % header-file in text format
ATRFILE= a(c).name; % attributes-file in binary format
DATAFILE=d(c).name; % data-file
SAMPLES2READ=660000; % number of samples to be read
% in case of more than one signal:
% 2*SAMPLES2READ samples are read
%------ LOAD HEADER DATA --------------------------------------------------
fprintf(1,'\\n$> WORKING ON %s ...\n', HEADERFILE);
signalh= fullfile(PATH, HEADERFILE);
fid1=fopen(signalh,'r');
z= fgetl(fid1);
A= sscanf(z, '%*s %d %d %d',[1,3]);
nosig= A(1); % number of signals
sfreq=A(2); % sample rate of data
clear A;
for k=1:nosig
z= fgetl(fid1);
A= sscanf(z, '%*s %d %d %d %d %d',[1,5]);
dformat(k)= A(1); % format; here only 212 is allowed
gain(k)= A(2); % number of integers per mV
bitres(k)= A(3); % bitresolution
zerovalue(k)= A(4); % integer value of ECG zero point
firstvalue(k)= A(5); % first integer value of signal (to test for errors)
end
fclose(fid1);
clear A;
signald= fullfile(PATH, DATAFILE); % data in format 212
fid2=fopen(signald,'r');
A= fread(fid2, [3, SAMPLES2READ], 'uint8')'; % matrix with 3 rows, each 8 bits long, = 2*12bit
fclose(fid2);
M2H= bitshift(A(:,2), -4); %字节向右移四位，即取字节的高四位
M1H= bitand(A(:,2), 15); %取字节的低四位
M( : , 1)= bitshift(M1H,8)+ A(:,1); %低四位向左移八位
M( : , 2)= bitshift(M2H,8)+ A(:,3); %高四位向左移八位
M = (M-1024)/200; %这个M就是咱们解码出来的数据
clear A M1H M2H PRR PRL;
fprintf(1,'\\n$> LOADING DATA FINISHED \n');
%------ LOAD ATTRIBUTES DATA ----------------------------------------------
atrd= fullfile(PATH, ATRFILE); % attribute file with annotation data
fid3=fopen(atrd,'r');
A= fread(fid3, [2, inf], 'uint8')';
fclose(fid3);
ATRTIME=[];
ANNOT=[];
sa=size(A);
saa=sa(1);
i=1;
while i<=saa
annoth=bitshift(A(i,2),-2);
if an
4000
noth==59
ANNOT=[ANNOT;bitshift(A(i+3,2),-2)];
ATRTIME=[ATRTIME;A(i+2,1)+bitshift(A(i+2,2),8)+...
bitshift(A(i+1,1),16)+bitshift(A(i+1,2),24)];
i=i+3;
elseif annoth==60
% nothing to do!
elseif annoth==61
% nothing to do!
elseif annoth==62
% nothing to do!
elseif annoth==63
hilfe=bitshift(bitand(A(i,2),3),8)+A(i,1);
hilfe=hilfe+mod(hilfe,2);
i=i+hilfe/2;
else
ATRTIME=[ATRTIME;bitshift(bitand(A(i,2),3),8)+A(i,1)];
ANNOT=[ANNOT;bitshift(A(i,2),-2)];
end
i=i+1;
end
ANNOT(length(ANNOT))=[]; % last line = EOF (=0)
ATRTIME(length(ATRTIME))=[]; % last line = EOF
clear A;
ATRTIME= (cumsum(ATRTIME)); %用来存放注释R波的位置。
ind= find(ATRTIME <= SAMPLES2READ);
ATRTIMED= ATRTIME(ind);
ANNOT=round(ANNOT);
ANNOTD= ANNOT(ind);
%------ DISPLAY DATA ------------------------------------------------------
figure(1); clf, box on, hold on
for k=1:length(ATRTIMED)
text(ATRTIMED(k),0,num2str(ANNOTD(k)));
end
%xlim([TIME(1), TIME(end)]);
xlabel('Time / s'); ylabel('Voltage / mV');
string=['ECG signal ',DATAFILE];
title(string);
fprintf(1,'\\n$> DISPLAYING DATA FINISHED \n');
% -------------------------------------------------------------------------
fprintf(1,'\\n$> ALL FINISHED \n');
%-----------------------保存数据----------------
len1=length(ATRTIME);
for t=4:len1-3 %保存分割的数据，前三个和后三个都不要
str=num2str(t,'%04d');
if(ANNOT(t)==1) %心电异常分类
z=78;
else
if(ANNOT(t)==28)
z=86;
else
z=79;
end
end

fd=num2str(c);
name=['S:\MIT-txt\',v(c).name(1:end-4) '-' str, '-' z,'.txt']; %文件命名
fid=fopen(name,'wt');
f=100;%向前取100点
b=199;%向后取100点
m1=ATRTIME(t)-f;
m2=ATRTIME(t)+b;
n=1;
for e=m1:1:m2

fprintf(fid,'%5.3f\n',M(e,l));
end
figure;
plot(M(m1:m2,l));
set(gcf,'visible','off');
axis off;
saveas(gcf,['S:\MIT-png\', v(c).name(1:end-4) '-' str, '-' z,'.png'])%图片命名
delete(gcf);

fclose(fid);
end
end