TensorFlow(十八)：从零开始训练图片分类模型

（一）：进入GitHub下载模型--》下载地址

因为我们需要slim模块，所以将包中的slim文件夹复制出来使用。

（1）：在slim中新建images文件夹存放图片集

（2）：新建model文件夹用来放模型

（3）：在datasets文件夹中新建myimages.py文件

# Copyright 2016 The TensorFlow Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ==============================================================================
"""Provides data for the flowers dataset.

The dataset scripts used to create the dataset can be found at:
tensorflow/models/slim/datasets/download_and_convert_flowers.py
"""

from __future__ import absolute_import
from __future__ import division
from __future__ import print_function

import os
import tensorflow as tf

from datasets import dataset_utils

slim = tf.contrib.slim

_FILE_PATTERN = 'image_%s_*.tfrecord'

SPLITS_TO_SIZES = {'train': 3500, 'test': 500}  # 这里根据自己的训练集内容进行修改

_NUM_CLASSES = 5

_ITEMS_TO_DESCRIPTIONS = {
    'image': 'A color image of varying size.',
    'label': 'A single integer between 0 and 4',
}


def get_split(split_name, dataset_dir, file_pattern=None, reader=None):
  """Gets a dataset tuple with instructions for reading flowers.

  Args:
    split_name: A train/validation split name.
    dataset_dir: The base directory of the dataset sources.
    file_pattern: The file pattern to use when matching the dataset sources.
      It is assumed that the pattern contains a '%s' string so that the split
      name can be inserted.
    reader: The TensorFlow reader type.

  Returns:
    A `Dataset` namedtuple.

  Raises:
    ValueError: if `split_name` is not a valid train/validation split.
  """
  if split_name not in SPLITS_TO_SIZES:
    raise ValueError('split name %s was not recognized.' % split_name)

  if not file_pattern:
    file_pattern = _FILE_PATTERN
  file_pattern = os.path.join(dataset_dir, file_pattern % split_name)

  # Allowing None in the signature so that dataset_factory can use the default.
  if reader is None:
    reader = tf.TFRecordReader

  keys_to_features = {
      'image/encoded': tf.FixedLenFeature((), tf.string, default_value=''),
      'image/format': tf.FixedLenFeature((), tf.string, default_value='png'),
      'image/class/label': tf.FixedLenFeature(
          [], tf.int64, default_value=tf.zeros([], dtype=tf.int64)),
  }

  items_to_handlers = {
      'image': slim.tfexample_decoder.Image(),
      'label': slim.tfexample_decoder.Tensor('image/class/label'),
  }

  decoder = slim.tfexample_decoder.TFExampleDecoder(
      keys_to_features, items_to_handlers)

  labels_to_names = None
  if dataset_utils.has_labels(dataset_dir):
    labels_to_names = dataset_utils.read_label_file(dataset_dir)

  return slim.dataset.Dataset(
      data_sources=file_pattern,
      reader=reader,
      decoder=decoder,
      num_samples=SPLITS_TO_SIZES[split_name],
      items_to_descriptions=_ITEMS_TO_DESCRIPTIONS,
      num_classes=_NUM_CLASSES,
      labels_to_names=labels_to_names)

（4）：修改dataset_factory.py

from datasets import myimages

datasets_map = {
    'cifar10': cifar10,
    'flowers': flowers,
    'imagenet': imagenet,
    'mnist': mnist,
    'myimages':myimages, # 这一句为添加的内容
}

（二）：对图片进行处理，生成tfrecord格式的文件。

import tensorflow as tf
import os
import random
import math
import sys


#验证集数量
_NUM_TEST = 500
#随机种子
_RANDOM_SEED = 0
#数据块数目
_NUM_SHARDS = 5
#数据集路径
DATASET_DIR = "C:/Users/FELIX/Desktop/tensor_study/slim/images/"
#标签文件名字
LABELS_FILENAME = ''.join([DATASET_DIR,'labels.txt'])

#定义tfrecord文件的路径+名字
def _get_dataset_filename(dataset_dir, split_name, shard_id):
    output_filename = 'image_%s_%05d-of-%05d.tfrecord' % (split_name, shard_id, _NUM_SHARDS)
    return os.path.join(dataset_dir, output_filename)

#判断tfrecord文件是否存在
def _dataset_exists(dataset_dir):
    for split_name in ['train', 'test']:
        for shard_id in range(_NUM_SHARDS):
            #定义tfrecord文件的路径+名字
            output_filename = _get_dataset_filename(dataset_dir, split_name, shard_id)
        if not tf.gfile.Exists(output_filename):
            return False
    return True

#获取所有文件以及分类
def _get_filenames_and_classes(dataset_dir):
    #数据目录
    directories = []
    #分类名称
    class_names = []
    for filename in os.listdir(dataset_dir):
        #合并文件路径
        path = os.path.join(dataset_dir, filename)
        #判断该路径是否为目录
        if os.path.isdir(path):
            #加入数据目录
            directories.append(path)
            #加入类别名称
            class_names.append(filename)

    photo_filenames = []
    #循环每个分类的文件夹
    for directory in directories:
        for filename in os.listdir(directory):
            path = os.path.join(directory, filename)
            #把图片加入图片列表
            photo_filenames.append(path)

    return photo_filenames, class_names

def int64_feature(values):
    if not isinstance(values, (tuple, list)):
        values = [values]
    return tf.train.Feature(int64_list=tf.train.Int64List(value=values))

def bytes_feature(values):
    return tf.train.Feature(bytes_list=tf.train.BytesList(value=[values]))

def image_to_tfexample(image_data, image_format, class_id):
    #Abstract base class for protocol messages.
    return tf.train.Example(features=tf.train.Features(feature={
      'image/encoded': bytes_feature(image_data),
      'image/format': bytes_feature(image_format),
      'image/class/label': int64_feature(class_id),
    }))

def write_label_file(labels_to_class_names, dataset_dir,filename=LABELS_FILENAME):
    labels_filename = os.path.join(dataset_dir, filename)
    with tf.gfile.Open(labels_filename, 'w') as f:
        for label in labels_to_class_names:
            class_name = labels_to_class_names[label]
            f.write('%d:%s
' % (label, class_name))

#把数据转为TFRecord格式
def _convert_dataset(split_name, filenames, class_names_to_ids, dataset_dir):
    assert split_name in ['train', 'test']
    #计算每个数据块有多少数据
    num_per_shard = int(len(filenames) / _NUM_SHARDS)
    with tf.Graph().as_default():
        with tf.Session() as sess:
            for shard_id in range(_NUM_SHARDS):
                #定义tfrecord文件的路径+名字
                output_filename = _get_dataset_filename(dataset_dir, split_name, shard_id)
                with tf.python_io.TFRecordWriter(output_filename) as tfrecord_writer:
                    #每一个数据块开始的位置
                    start_ndx = shard_id * num_per_shard
                    #每一个数据块最后的位置
                    end_ndx = min((shard_id+1) * num_per_shard, len(filenames))
                    for i in range(start_ndx, end_ndx):
                        try:
                            sys.stdout.write('
>> Converting image %d/%d shard %d' % (i+1, len(filenames), shard_id))
                            sys.stdout.flush()
                            #读取图片
                            image_data = tf.gfile.FastGFile(filenames[i], 'rb').read() # 这里一定要rb否则会出现编码错误
                            #获得图片的类别名称
                            class_name = os.path.basename(os.path.dirname(filenames[i]))
                            #找到类别名称对应的id
                            class_id = class_names_to_ids[class_name]
                            #生成tfrecord文件
                            example = image_to_tfexample(image_data, b'jpg', class_id)
                            tfrecord_writer.write(example.SerializeToString())
                        except IOError as e:
                            print("Could not read:",filenames[i])
                            print("Error:",e)
                            print("Skip it
")
                            
    sys.stdout.write('
')
    sys.stdout.flush()


if __name__ == '__main__':
    #判断tfrecord文件是否存在
    if _dataset_exists(DATASET_DIR):
        print('tfcecord文件已存在')
    else:
        #获得所有图片以及分类
        photo_filenames, class_names = _get_filenames_and_classes(DATASET_DIR)
        #把分类转为字典格式，类似于{'house': 3, 'flower': 1, 'plane': 4, 'guitar': 2, 'animal': 0}
        class_names_to_ids = dict(zip(class_names, range(len(class_names))))

        #把数据切分为训练集和测试集
        random.seed(_RANDOM_SEED)
        random.shuffle(photo_filenames)
        training_filenames = photo_filenames[_NUM_TEST:]
        testing_filenames = photo_filenames[:_NUM_TEST]

        #数据转换
        _convert_dataset('train', training_filenames, class_names_to_ids, DATASET_DIR)
        _convert_dataset('test', testing_filenames, class_names_to_ids, DATASET_DIR)

        #输出labels文件
        labels_to_class_names = dict(zip(range(len(class_names)), class_names))
        write_label_file(labels_to_class_names, DATASET_DIR)

 （三）：新建批处理文件，开始训练模型

python C:/Users/FELIX/Desktop/tensor_study/slim/train_image_classifier.py ^
--train_dir=C:/Users/FELIX/Desktop/tensor_study/slim/model ^
--dataset_name=myimages ^
--dataset_split_name=train ^
--dataset_dir=C:/Users/FELIX/Desktop/tensor_study/slim/images ^
--batch_size=10 ^
--max_number_of_steps=10000 ^
--model_name=inception_v3 ^
pause



注释：
第一行表示运行训练文件，路径为全路径
第二行表示模型存放位置
第三行为创建的myimages文件名
第四行为使用的训练集
第五行为数据集所在的位置
第六行为批次大小，默认为32，看个人GPU，我用10
第七行为训练次数，默认无限次
第八行为使用模型名称