基于matlab开发的光谱数据预处理程序，包括MSC,SNV,归一化，中心化，导数等等.rar

clc; clear; close all; %% 打开多个txt文件 path = uigetdir('D:\','Pick a Directory'); files = dir([path, '\*.txt']); for i = 1:length(files) data(:,2*i-1:2*i) = load( [path '\' files(i).name] ); end %% 作图 color=['r','g','b','c','m','y','k']; figure(1); for j=1:i A=data(:,2*j-1); B=data(:,2*j); %c1 = randint(1,1,[1,length(color)]); % 产生随机数 c1 = randi([1,length(color)],1,1); % 产生随机数 c2 = color(c1); % 确定随机颜色 set(gca,'XDir','reverse'); % 横坐标从大到小 hold on; plot(A,B,c2); title('光谱图'); xlabel('Wavenumber(cm-1)'); ylabel('Absorbance'); end %% 吸光度波数 Absorbance=data(:,2:2:end); %得到吸光度 Absorbance=Absorbance'; [Absorbance_m,Absorbance_n]=size(Absorbance); Wavenumber=data(:,1:2:end); %得到波数 Wavenumber=Wavenumber'; Absorbance_mean=mean(Absorbance);%每个样本吸光度平均 %% 多元散射校正MSC Absorbance_msc=msc(Absorbance,Absorbance_mean); figure(2); for sample=1:1:Absorbance_m plot(Wavenumber(1,:),Absorbance_msc(sample,:),'-r'); hold on; end set(gca,'XDir','reverse'); % 横坐标从大到小 title('多元散射校正MSC'); xlabel('Wavenumber(cm-1)'); ylabel('Absorbance'); %% 标准正态变量交化SNV Absorbance_snv=snv(Absorbance); figure(3); for sample=1:1:Absorbance_m plot(Wavenumber(1,:),Absorbance_snv(sample,:),'-g'); hold on; end set(gca,'XDir','reverse'); % 横坐标从大到小 title('标准正态变量交化SNV'); xlabel('Wavenumber(cm-1)'); ylabel('Absorbance'); %% 归一化Normalize [Absorbance_Nor] = normaliz(Absorbance); figure(4); for sample=1:1:Absorbance_m plot(Wavenumber(1,:),Absorbance_Nor(sample,:),'-b'); hold on; end set(gca,'XDir','reverse'); % 横坐标从大到小 title('归一化Normalize'); xlabel('Wavenumber(cm-1)'); ylabel('Absorbance'); %% 数据中心化(Mean centering) [Absorbance_MCX,Absorbance_MX] = center(Absorbance); figure(5); for sample=1:1:Absorbance_m plot(Wavenumber(1,:),Absorbance_MCX(sample,:),'-c'); hold on; end set(gca,'XDir','reverse'); % 横坐标从大到小 title('数据中心化(Mean centering)'); xlabel('Wavenumber(cm-1)'); ylabel('Absorbance'); %% 标准化Autoscales [ax,mx,stdx] = auto((Absorbance)'); ax=ax'; figure(6); for sample=1:1:Absorbance_m plot(Wavenumber(1,:),ax(sample,:),'-m'); hold on; end set(gca,'XDir','reverse'); % 横坐标从大到小 title('标准化Autoscales'); xlabel('Wavenumber(cm-1)'); ylabel('Absorbance'); warning('off') %% 移动窗口平滑/Moving-average method Absorbance_nir=nirmaf(Absorbance,11); figure(7); for sample=1:1:Absorbance_m plot(Wavenumber(1,:),Absorbance_nir(sample,:),'-r'); hold on; end set(gca,'XDir','reverse'); % 横坐标从大到小 title('移动窗口平滑光谱'); xlabel('Wavenumber(cm-1)'); ylabel('Absorbance'); %% SavitZky一Golay卷积平滑法及求导 Absorbance_S_G =savgol(Absorbance,15);%光谱，窗口大小；多项式项数；一阶求导;平滑; Absorbance_S_G1 = savgol(Absorbance,7,3,1);%一阶求导 Absorbance_S_G2 = savgol(Absorbance,7,3,2);%二阶求导 figure(8); for sample=1:1:Absorbance_m plot(Wavenumber(1,:),Absorbance_S_G(sample,:),'-k'); hold on; end set(gca,'XDir','reverse'); % 横坐标从大到小 title('SavitZky-Golay卷积平滑法'); xlabel('Wavenumber(cm-1)'); ylabel('Absorbance'); figure(9); for sample=1:1:Absorbance_m plot(Wavenumber(1,:),Absorbance_S_G1(sample,:),'-r'); hold on; end set(gca,'XDir','reverse'); % 横坐标从大到小 title('SavitZky-Golay一阶求导'); xlabel('Wavenumber(cm-1)'); ylabel('Absorbance'); figure(10); for sample=1:1:Absorbance_m plot(Wavenumber(1,:),Absorbance_S_G2(sample,:),'-g'); hold on; end set(gca,'XDir','reverse'); % 横坐标从大到小 title('SavitZky-Golay二阶求导'); xlabel('Wavenumber(cm-1)'); ylabel('Absorbance'); %% 直接差分一、二阶求导 d1=diff((Absorbance)',1);% d2=diff((Absorbance)',2);% d1=d1'; d2=d2'; figure(11); for sample=1:1:Absorbance_m-1 plot(Wavenumber(1,2:1:end),d1(sample,:),'-b'); hold on; end set(gca,'XDir','reverse'); % 横坐标从大到小 title('直接差分一阶求导'); xlabel('Wavenumber(cm-1)'); ylabel('Absorbance'); figure(12); for sample=1:1:Absorbance_m-2 plot(Wavenumber(1,3:1:end),d2(sample,:),'-r'); hold on; end set(gca,'XDir','reverse'); % 横坐标从大到小 title('直接差分二阶求导'); xlabel('Wavenumber(cm-1)'); ylabel('Absorbance');