制作mnist格式数据集

import os
from PIL import Image
from array import *
from random import shuffle

# # 文件组织架构：
# ├──training-images
# │   └──0（类别为0的图像）
# │   ├──1（类别为1的图像）
# │   ├──2（类别为2的图像）
# │   ├──3（类别为3的图像）
# │   └──4（类别为4的图像）
# ├──test-images
# │   └──0（类别为0的图像）
# │   ├──1（类别为1的图像）
# │   ├──2（类别为2的图像）
# │   ├──3（类别为3的图像）
# │   └──4（类别为4的图像）
# └── mnist数据集制作.py（本脚本）

# Load from and save to
Names = [['./training-images', 'train'], ['./test-images', 'test']]

for name in Names:

    data_image = array('B')
    data_label = array('B')

    print(os.listdir(name[0]))
    FileList = []
    for dirname in os.listdir(name[0])[0:]:  # [1:] Excludes .DS_Store from Mac OS
        # print(dirname)
        path = os.path.join(name[0], dirname)
        # print(path)
        for filename in os.listdir(path):
            # print(filename)
            if filename.endswith(".png"):
                FileList.append(os.path.join(name[0] + '/', dirname + '/', filename))
        print(FileList)
    shuffle(FileList)  # Usefull for further segmenting the validation set

    for filename in FileList:

        label = int(filename.split('/')[2])
        print(filename)
        Im = Image.open(filename)
        # print(Im)

        pixel = Im.load()

        width, height = Im.size

        for x in range(0, width):
            for y in range(0, height):
                data_image.append(pixel[y, x])

        data_label.append(label)  # labels start (one unsigned byte each)

    hexval = "{0:#0{1}x}".format(len(FileList), 6)  # number of files in HEX

    # header for label array

    header = array('B')
    header.extend([0, 0, 8, 1, 0, 0])
    header.append(int('0x' + hexval[2:][:2], 16))
    header.append(int('0x' + hexval[2:][2:], 16))

    data_label = header + data_label

    # additional header for images array

    if max([width, height]) <= 256:
        header.extend([0, 0, 0, width, 0, 0, 0, height])
    else:
        raise ValueError('Image exceeds maximum size: 256x256 pixels');

    header[3] = 3  # Changing MSB for image data (0x00000803)

    data_image = header + data_image

    output_file = open(name[1] + '-images-idx3-ubyte', 'wb')
    data_image.tofile(output_file)
    output_file.close()

    output_file = open(name[1] + '-labels-idx1-ubyte', 'wb')
    data_label.tofile(output_file)
    output_file.close()

# 运行脚本得到四个文件test-images-idx3-ubyte、test-labels-idx1-ubyte、train-images-idx3-ubyte、train-labels-idx1-ubyte
# 在cmd中利用tar -czvf命令对上述四个文件压缩得到最终的mnist格式数据集