Matlab的用法总结

1. 对序列进行洗牌 randperm()

randperm()产生随机的序列
%if filepaths 是一个5*1的结构体,then cshuffle = randperm(length(filepaths)) %对filepaths进行随机的洗牌,得到了 cshuffle => [2,5,4,1,3] 洗牌后的序列

2. 图像灰度化 rgb2gray()

MyYuanLaiPic = imread('e:/image/matlab/Cluo.jpg');%读取RGB格式的图像
MyFirstGrayPic = rgb2gray(MyYuanLaiPic);%用已有的函数进行RGB到灰度图像的转换 [rows , cols , colors] = size(MyYuanLaiPic);%得到原来图像的矩阵的参数
MidGrayPic = zeros(rows , cols);%用得到的参数创建一个全零的矩阵,这个矩阵用来存储用下面的方法产生的灰度图像
MidGrayPic = uint8(MidGrayPic);%将创建的全零矩阵转化为uint8格式,因为用上面的语句创建之后图像是double型的 for i = :rows
for j = :cols
sum = ;
for k = :colors
sum = sum + MyYuanLaiPic(i , j , k) / ;%进行转化的关键公式,sum每次都因为后面的数字而不能超过255
end
MidGrayPic(i , j) = sum;
end
end
imwrite(MidGrayPic , 'E:/image/matlab/Cluo.png' , 'png'); %显示原来的RGB图像
figure();
imshow(MyYuanLaiPic); %显示经过系统函数运算过的灰度图像
figure();
imshow(MyFirstGrayPic); %显示转化之后的灰度图像
figure();
imshow(MidGrayPic);

3. 对图像进行旋转和翻转

function I = data_augmentation(I, K)

if K ==
return;
elseif K == % flipped
I = flipud(I);
return;
elseif K == % rotation
I = rot90(I,);
return;
elseif K == % rotation & flipped
I = rot90(I,);
I = flipud(I);
return;
elseif K == % rotation
I = rot90(I,);
return;
elseif K == % rotation & flipped
I = rot90(I,);
I = flipud(I);
return;
elseif K == % rotation
I = rot90(I,);
return;
elseif K == % rotation & flipped
I = rot90(I,);
I = flipud(I);
return;
end

4. 对array进行连接 cat(dim, A, B)

Matlab的用法总结

5.对图像进缩放,imresize()

HR_current  = imresize(HR,nscales(j,i),'bicubic');
%第二个参数为缩放因子,e.g. 0.5、0.8
%第三个参数为缩放method

6.读取图像默认的数据类型uint8,最大值为255;但是在进行图形矩阵的操作和变化过程中非常容易溢出,所以需要转化为double(64为,0~1)或者single

im2double()将值0~255映射到0~1之间

7.两个循环搞定patch的获取

 for x = +step1 : stride : (hei-patchsize+)
for y = +step2 : stride : (wid-patchsize+)
count = count + ;
subim_label = HR_current(x : x+patchsize-, y : y+patchsize-,:nch);
imdb.HRlabels(:, :, :, count) = subim_label;
if count<=diffPatches %不够一个patch进行填充
imdb.HRlabels(:, :, :, end-count+) = HR_current(x : x+patchsize-, y : y+patchsize-,:nch);
end
end
end

8.产生图像的patch

function [imdb] = generatepatches

%% Note, set your training image set first, large dataset is prefered!
folders = {'path_of_your_training_dataset'}; % set this first! stride = ; % control the number of image patches
patchsize = ; batchSize = ; % important for BNorm
count = ;
nch = ; % for grayscale image, for color image step1 = ;
step2 = ; ext = {'*.jpg','*.png','*.bmp'};
filepaths = []; for j = :length(folders)
for i = : length(ext)
filepaths = cat(,filepaths, dir(fullfile(folders{j}, ext{i}))); %获取folder获取所有figure
end
end cshuffle = randperm(length(filepaths)); % randperm获取filepaths的随机排列
nimages = round(length(filepaths)); % control the number of image patches 去整数 ns = ;
nscales = min(,0.45 + 0.05*randi(,[ns,nimages])); %产生随机矩阵 * all values are less than
naugment = randi(,[,nimages]); %产生一个随机矩阵1* all values are form - for i = : nimages
% HR = imread(fullfile(filepaths(cshuffle(i)).folder,filepaths(cshuffle(i)).name));
HR = imread(fullfile(folders{},filepaths(cshuffle(i)).name)); %从文件夹里随机读取一张图片
HR = HR(:,:,); %如果是rgb图就获取一个通道的,如果是gray图则自然为该图像 HR = data_augmentation(HR, naugment(i)); % 数据增大data_augmentation data_augmentation(HR, ); 转到data_augmentation.m里面就将图片旋转90度
disp([i,nimages,round(count/batchSize)]) for j = : size(nscales,) % size(nscales,) 为1 HR_current = imresize(HR,nscales(j,i),'bicubic'); %对图像进行尺度的缩放
[hei,wid,~] = size(HR_current); % 得到此时的高和宽
for x = +step1 : stride : (hei-patchsize+) % 产生的patch (hei-patchsize+)这个value是一个临界值,最后放不了一个patch
for y = +step2 : stride : (wid-patchsize+)
count=count+;
end
end
end
end numPatches = ceil(count/batchSize)*batchSize; %ceil(1.2)=> ceil(0.2)=> 总共有多少个patch
diffPatches = numPatches - count; % 真实的差了多少个patch
disp([numPatches,numPatches/batchSize,diffPatches]); disp('-----------------------------'); %------------------------------------------------------------------
%------------------------------------------------------------------ count = ;
imdb.HRlabels = zeros(patchsize, patchsize, nch, numPatches,'single'); %imdb是一个结构体 *** for i = : nimages
% HR = imread(fullfile(filepaths(cshuffle(i)).folder,filepaths(cshuffle(i)).name));
HR = imread(fullfile(folders{},filepaths(cshuffle(i)).name)); %从文件夹里随机读取一张图片 if nch == && size(HR,) == %rgb2gray
HR = rgb2gray(HR);
end HR = data_augmentation(HR, naugment(i)); % 图像旋转操作
disp([i,nimages,round(count/)]) for j = : size(nscales,) HR_current = imresize(HR,nscales(j,i),'bicubic'); %图像进行随机的缩放
[hei,wid,~] = size(HR_current);
HR_current = im2single(HR_current); for x = +step1 : stride : (hei-patchsize+)
for y = +step2 : stride : (wid-patchsize+)
count = count + ;
subim_label = HR_current(x : x+patchsize-, y : y+patchsize-,:nch);
imdb.HRlabels(:, :, :, count) = subim_label;
if count<=diffPatches %不够一个patch进行填充
imdb.HRlabels(:, :, :, end-count+) = HR_current(x : x+patchsize-, y : y+patchsize-,:nch);
end
end
end
end
end imdb.set = uint8(ones(,size(imdb.HRlabels,)));

9.求某一个矩阵的指定维度的大小

size(A,dims) = value
# 如xx是一个16*401的矩阵,则求到第一维度的大小16 size(xx,1) =>16 # 如xx是一个16*401的矩阵,则求到第二维度的大小401 size(xx,2) =>401

  

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