www.gusucode.com > 光谱读入、降噪和去背景一体化matlab 源码 > 光谱读入、降噪和去背景一体化matlab 源码/wavelet_denoise_deback_pw.m

    clear;clc;
dir='D:\m\';%%%%%%%%%% 输入文件所在目录
%%%%%%%%%% read the signal of background.
fname='background-15mw-500um-10s.txt';%输入文件名
filename=strcat(dir,fname);%%%%%%%%%% 构成文件路径
fid=fopen(filename,'r');
num=fscanf(fid,'%f %f',[2,inf]);
fclose(fid);
bg_y=num(2,:);bg_x=num(1,:); %backgroud后的信号
subplot(4,1,1);plot(bg_x,bg_y,'b');grid;;%画出原始信号波形，同时画四个
title('backgroud signal');
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
fname='glu-15mw-500um-10s-2.txt';%the filename of nacl
filename=strcat(dir,fname);
fid=fopen(filename,'r');
num=fscanf(fid,'%f %f',[2,inf]);
fclose(fid);
NL_y=num(2,:);NL_x=num(1,:); %nacl信号
%NL_y=num(2,:)-mean(num(2,3110:3189));NL_x=num(1,:); %去直流分量的nacl信号
subplot(4,1,2);plot(NL_x,NL_y,'r');grid;;%画出nacl原始信号波形
title('glue signal');

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%% use wavelet to realize the filter.
dn=wden(bg_y,'sqtwolog','s','sln',5,'sym8');% sqtlog,sln 组合滤波毛刺最少最光滑
%wden have several threshold selection rules:'rigrsure' uses the principle 
%of Stein's Unbiased Risk . 'heursure' is an heuristic variant of the first option.
% 'sqtwolog' for universal threshold  'minimaxi'for minimax thresholding
% sym8 is one kind of wavelets.'s' is the soft,(the other is  hard)  thresholding. 
subplot(4,1,3);plot(NL_x,dn,'g');
title('de-noised signal');grid;

%%%%% remove the backgound signal
y=NL_y-dn;
subplot(4,1,4);plot(NL_x,y,'k');;title('remove backgroup');grid; %%%%%%%画出原始信号波形
title('glue signal removes the bacground');
newfilename=strcat(dir,'de_background_',fname);%输出文件为:de_backgroud_ + 原文件名
fid=fopen(newfilename,'wt');
count=fprintf(fid, '%4.2f %3.4f\n', cat(1,NL_x,y)); %%输出滤波后信号到文件
fclose(fid);