MATLAB实例：读取Fashion MNIST数据，保存为.mat文件，并展示部分样例

作者：凯鲁嘎吉 - 博客园 http://www.cnblogs.com/kailugaji/

Fashion MNIST数据来源：https://github.com/zalandoresearch/fashion-mnist

Name	Content	Examples	Size	Link	MD5 Checksum
`train-images-idx3-ubyte.gz`	training set images	60,000	26 MBytes	Download	`8d4fb7e6c68d591d4c3dfef9ec88bf0d`
`train-labels-idx1-ubyte.gz`	training set labels	60,000	29 KBytes	Download	`25c81989df183df01b3e8a0aad5dffbe`
`t10k-images-idx3-ubyte.gz`	test set images	10,000	4.3 MBytes	Download	`bef4ecab320f06d8554ea6380940ec79`
`t10k-labels-idx1-ubyte.gz`	test set labels	10,000	5.1 KBytes	Download	`bb300cfdad3c16e7a12a480ee83cd310`

MATLAB程序

demo.m

clear
clc
% Author：kailugaji https://www.cnblogs.com/kailugaji/
filename_data=\'E:\database\MNIST\Fashion MNIST\t10k-images-idx3-ubyte\t10k-images-idx3-ubyte\'; %自行修改路径
data = loadMNISTImages(filename_data);
data=data\';
filename_label=\'E:\database\MNIST\Fashion MNIST\t10k-labels-idx1-ubyte\t10k-labels-idx1-ubyte\'; %自行修改路径
real_label = loadMNISTLabels(filename_label);
%     标签	所代表的意思
%     0	短袖圆领T恤
%     1	裤子
%     2	套衫
%     3	连衣裙
%     4	外套
%     5	凉鞋
%     6	衬衫
%     7	运动鞋
%     8	包
%     9	短靴
%  real_label(real_label==0)=10;
save fashion_MNIST data real_label

Image_samples=Image_integration(data, real_label, 10);
A=mat2gray(Image_samples);
figure(1)
imshow(A, \'Border\',\'tight\');
print(gcf,\'-r1000\',\'-djpeg\',\'My_Fashion_MNIST.jpg\');

loadMNISTImages.m

function images = loadMNISTImages(filename)
%load MNIST Images returns a 28x28x[number of MNIST images] matrix containing
% 原链接：https://blog.csdn.net/tracer9/article/details/51253604
%the raw MNIST images
 
fp = fopen(filename, \'rb\');
assert(fp ~= -1, [\'Could not open \', filename, \'\']);
 
magic = fread(fp, 1, \'int32\', 0, \'ieee-be\');
assert(magic == 2051, [\'Bad magic number in \', filename, \'\']);
 
numImages = fread(fp, 1, \'int32\', 0, \'ieee-be\');
numRows = fread(fp, 1, \'int32\', 0, \'ieee-be\');
numCols = fread(fp, 1, \'int32\', 0, \'ieee-be\');
 
images = fread(fp, inf, \'unsigned char\');
images = reshape(images, numCols, numRows, numImages);
images = permute(images,[2 1 3]);
 
fclose(fp);
 
% Reshape to #pixels x #examples
images = reshape(images, size(images, 1) * size(images, 2), size(images, 3));
% Convert to double and rescale to [0,1]
images = double(images) / 255;

loadMNISTLabels.m

function labels = loadMNISTLabels(filename)
% load MNIST Labels returns a [number of MNIST images]x1 matrix containing
% 原链接：https://blog.csdn.net/tracer9/article/details/51253604
% the labels for the MNIST images
fp = fopen(filename, \'rb\');
assert(fp ~= -1, [\'Could not open \', filename, \'\']);
magic = fread(fp, 1, \'int32\', 0, \'ieee-be\');
assert(magic == 2049, [\'Bad magic number in \', filename, \'\']);
numLabels = fread(fp, 1, \'int32\', 0, \'ieee-be\');
labels = fread(fp, inf, \'unsigned char\');
assert(size(labels,1) == numLabels, \'Mismatch in label count\');
fclose(fp);

Image_integration.m

function Image_samples=Image_integration(data, real_label, N_samples)
% Gray image integration
% This code only applies to square matrices
% Input:
% data: dataset. N*Dim
% real_label: GroundTruth. N*1
% N_samples: number of selected samples
% Output:
% Image_samples:Integrated image
% Author: kailugaji https://www.cnblogs.com/kailugaji/
[~, Dim]=size(data);
[real_label, b]=sort(real_label);
data=data(b, :);
K=length(unique(real_label)); % number of cluster
[~, ID]=unique(real_label);
ID=ID-1;
image_10=cell(N_samples, K);
temp=cell(N_samples, K);
Image_samples=[];
for i=1:N_samples
    for j=1:K
        temp{i, j}=reshape(data(ID(j)+i, :), sqrt(Dim), sqrt(Dim)); % you can change its size
        image_10{i, j}=[image_10{i, j}, temp{i, j}];
    end
    Image_samples=[Image_samples; image_10{i, :}];
end

结果

数据已经转换成.mat格式，同时保存在和MATLAB程序同目录下。

每一类取了10个样例来展示。

参考

[1] GitHub - zalandoresearch/fashion-mnist: A MNIST-like fashion product database. Benchmark

[2] MATLAB小函数：展示灰度图像数据集的部分样例 - 凯鲁嘎吉 - 博客园

[3]【机器学习】MATLAB读取mnist数据库_心所愿，力必坚！-CSDN博客

注意：传统的MNIST数据也可以采用相同的方式进行转化成.mat文件，只需把路径改一下，换成MNIST的路径即可。