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⛄ 内容介绍
心血管疾病是当今危害人类身体健康的主要疾病之一,而心电图检查是临床上诊断心血管疾病的重要方法,如何利用计算机对心电图(ECG)进行快速、自动、准确的分析一直是国内外学者的热门课题。 心电图(ECG)是与心脏搏动相关的电位变化图,由于心电图各波形的形状及其间隔皆与心脏的电气特性有直接的关系,所以医生可以籍此判定心脏微电气活动中的异常,从而诊断出各种不同的心脏疾病,并且可用来监测病人的安危、评估病情的进展和治疗成效等。基于小波变换DWT实现ECG信号心率计算.
⛄ 部分代码
%**************************************************************************
% Outputs a .MAT matrix
% The matrix can then be used in the Wavelets toolbox.
% This program is based on rddata.m by Robert Tratnig.
% The algorithm was based on a program written by Klaus Rheinberger.
% 10May05 - Updated so output file name was how I wanted it
% 17 May 2005 - Added check that input contains exactly two signals -- GBM
%**************************************************************************
clc; clear all; close all;
%**************************************************************************
% Get Data & User Inputs
%**************************************************************************
PATH = input('Path Where Data Is Stored, Else Leave Blank = ','s');
FILE = input('ECG File Name = ','s'); % Input String Filename
HEADERFILE = strcat(FILE,'.hea'); % Header In TXT Format
ATRFILE = strcat(FILE,'.atr'); % Attributes In Binary Format
DATAFILE = strcat(FILE,'.dat'); % ECG Data File
SAMPLESTART = input('ECG Start Time = ','s');
SAMPLEEND = input('ECG End Time = ','s');
SAMPLESTART_1 = str2num(SAMPLESTART); % The Start Time In Seconds
SAMPLEEND_1 = str2num(SAMPLEEND); % The End Time In Seconds
%**************************************************************************
% 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
if nosig ~= 2
error('Error: Input must have exactly 2 signals');
end;
sfreq = A(2); % Sample Rate Of Data
SAMPLESTART_2 = sfreq * SAMPLESTART_1; % Samples/Second * Seconds
SAMPLEEND_2 = sfreq * SAMPLEEND_1; % Samples/Second * Seconds
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 - 212 Only
gain(k) = A(2); % Integers Per mV
bitres(k) = A(3); % Bit Resolution
zerovalue(k) = A(4); % Value Of ECG Zero Point
firstvalue(k) = A(5); % First Value Of Signal
end;
fclose(fid1);
clear A;
%**************************************************************************
% Fix Minor Data Problems
%**************************************************************************
if SAMPLESTART_2 == 0 % If User Starts At Zero
SAMPLESTART_2 = 1; % We Start At The First Entry
end;
if SAMPLEEND_1 == 0 % If User Wants To End At Zero
error('Error: Results In No ECG Data');
end;
if SAMPLESTART_1 < 0 | SAMPLEEND_1 < 0 % If User Enters Negative Time
error('Error: ECG Start & End Time Must Be Positive');
end;
if SAMPLESTART_1 > SAMPLEEND_1 % If User Sets End Before Start
error('Error: ECG Start Time Should Be Before ECG End Time');
end;
%**************************************************************************
% Load Binary Data
%**************************************************************************
if dformat ~= [212,212], error('Error: File Not 212 Binary Format'); end;
signald = fullfile(PATH, DATAFILE); % Data In 212 Format
fid2 = fopen(signald,'r');
A = fread(fid2, [3, SAMPLEEND_2], 'uint8')';
fclose(fid2);
M2H = bitshift(A(:,2), -4);
M1H = bitand(A(:,2), 15);
PRL = bitshift(bitand(A(:,2),8),9); % Sign Bit
PRR = bitshift(bitand(A(:,2),128),5); % Sign Bit
M( : , 1) = bitshift(M1H,8)+ A(:,1)-PRL;
M( : , 2) = bitshift(M2H,8)+ A(:,3)-PRR;
if M(1,:) ~= firstvalue, error('Error: 1st Bit Values Inconsistent'); end;
switch nosig
case 2
M( : , 1) = (M( : , 1) - zerovalue(1))/gain(1);
M( : , 2) = (M( : , 2) - zerovalue(2))/gain(2);
TIME = (0:(SAMPLEEND_2 - 1))/sfreq;
case 1
M( : , 1) = (M( : , 1) - zerovalue(1));
M( : , 2) = (M( : , 2) - zerovalue(1));
M = M';
M(1) = [];
sM = size(M);
sM = sM(2)+1;
M(sM) = 0;
M = M';
M = M/gain(1);
TIME = (0:2*(SAMPLEEND_2)-1)/sfreq;
otherwise
disp('Error: Sorting Algorithm For > 2 Signals Not Programmed Yet!');
end;
clear A M1H M2H PRR PRL;
fprintf(1,'\\n$> LOADING DATA FINISHED \n');
%**************************************************************************
% Load Attributes Data
%**************************************************************************
atrd = fullfile(PATH, ATRFILE);
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 annoth == 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
elseif annoth == 61
elseif annoth == 62
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;
ECG_1_Temp = M(:,1);
ECG_1 = ECG_1_Temp(SAMPLESTART_2 : SAMPLEEND_2);
if nosig == 2
ECG_2_Temp = M(:,2);
ECG_2 = ECG_2_Temp(SAMPLESTART_2 : SAMPLEEND_2);
end;
Time_Adjusted = TIME(SAMPLESTART_2 : SAMPLEEND_2);
%**************************************************************************
% Display Data
%**************************************************************************
figure(1); clf, box on, hold on
plot(Time_Adjusted, ECG_1,'r');
if nosig == 2
plot(Time_Adjusted, ECG_2,'b');
end;
for k = 1:length(ATRTIMED)
text(ATRTIMED(k),0,num2str(ANNOTD(k)));
end;
xlim([Time_Adjusted(1), Time_Adjusted(end)]);
xlabel('Time (Seconds)'); ylabel('Voltage (mV)');
string = ['ECG Signal ',DATAFILE];
title(string);
fprintf(1,'\\n$> DISPLAYING DATA FINISHED \n');
%**************************************************************************
% Output Data File Into Current Working Directory
%**************************************************************************
save(strcat(FILE,'_ECG_',SAMPLESTART,'_',SAMPLEEND) ...
, 'ECG_1' , 'ECG_2' , 'Time_Adjusted');
fprintf(1,'\\n$> ALL FINISHED \n');
%**************************************************************************
% End Of Code
%**************************************************************************
⛄ 运行结果
⛄ 参考文献
[1]张锦. 基于小波变换的ECG信号去噪研究[J]. 电脑知识与技术：学术版, 2017, 13(11):3.
[2]杨旭东. 基于小波变换的ECG信号特征参数提取研究[D]. 电子科技大学.
