关于matconvnet数据预处理方法的思考(一)

    xiaoxiao2021-04-13  28

    这一部分只要讲解怎么把我们的图片数据变成matconvnet可以用来训练的数据格式。主要是套用minst的数据结构。 第一种是把所有的图片放在一个文件夹中,但同一类命名相似,比如第一类:1_1.bmp ,1_2.bmp···第二类:2_1.bmp,2_2.bmp···

    srcDir=uigetdir('F:\手掌静脉图像\增强500类未分组\'); %获得选择的文件夹 cd(srcDir);%需要手动点击选择 allnames=struct2cell(dir('*.bmp')); %只处理8位的bmp文件 len=size(allnames,2); %获得bmp文件的个数 Sample_num = 12;%这种处理方法最好每类的样本数量是一致的,比如我这里每类都有12张图片 Num = len/Sample_num;%用文件夹内总的图片数len除以每类的图片数Sample_num得到类数Num Images = zeros(128,128,len); Labels = zeros(1,len); for k=1:len %逐次取出文件 name=allnames{1,k};%这里可以自己显示一下allnames看一下图片的结构 Images(:,:,k)=imread(name); Labels(1,k) = ceil((k)/Sample_num);%天花板取整,给每类打上标签 end train_sample_num = 8; %标定每类中的训练样本数量 images = zeros(128,128,train_sample_num * Num); labels = zeros(1,train_sample_num * Num); for n = 0 : Num-1 labels(1,(n * train_sample_num+1):(n * train_sample_num +train_sample_num))=Labels(1,(n * Sample_num+1):(n * Sample_num + train_sample_num)); %取出Labels中每类的前train_sample_num个标签赋值给训练集的labels images(:,:,(n * train_sample_num+1):((n * train_sample_num +train_sample_num))) = Images(:,:,(n * Sample_num+1):(n * Sample_num + train_sample_num)); %同理,取出Images中每类的前train_sample_num个图像赋值给训练集的images end save('train_data','images','labels') val_sample_num = 2; %标定每类中的验证样本数量 images = zeros(128,128,val_sample_num * Num); labels = zeros(1,val_sample_num * Num); for n = 0 : Num-1 labels(1,(n * val_sample_num+1):(n * val_sample_num + val_sample_num))=Labels(1,(n * Sample_num+train_sample_num+1):(n * Sample_num + train_sample_num+val_sample_num)); images(:,:,(n * val_sample_num+1):(n * val_sample_num + val_sample_num))=Images(:,:,(n * Sample_num+train_sample_num+1):(n * Sample_num + train_sample_num+val_sample_num)); end save('val_data','images','labels') test_sample_num = 4; %标定测试样本 images = zeros(128,128,test_sample_num * Num); labels = zeros(1,test_sample_num * Num); for n = 0 : Num-1 labels(1,(n * test_sample_num+1):(n * test_sample_num + test_sample_num))=Labels(1,((n+1) * Sample_num - test_sample_num +1):((n+1) * Sample_num )); images(:,:,(n * test_sample_num+1):(n * test_sample_num + test_sample_num))=Images(:,:,((n+1) * Sample_num - test_sample_num +1):((n+1) * Sample_num )); end save('test_data','images','labels') %注意读懂在3个for循环中是怎样把Labels和Images分成train、val、test三个部分的

    与此种处理方式相承接的主程序写法:

    data1=load('val_data.mat'); data2=load('train_data.mat'); data3=load('test_data.mat'); set=[3*ones(1,numel(data1.labels)) 1*ones(1,numel(data2.labels)) 2*ones(1,numel(data3.labels))]; data=single(reshape(cat(3,data1.images,data2.images,data3.images),128,128,1,[])); dataMean=mean(data(:,:,:,set==1),4); data=bsxfun(@minus,data,dataMean); labels=cat(2,data1.labels,data2.labels,data3.labels); imdb.images.data=data; imdb.images.data_mean=dataMean; imdb.images.labels=labels; imdb.images.set=set; imdb.meta.sets={'train','val','test'};%??存疑 save( 'imdb.mat', '-struct', 'imdb') ;
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