Tensorflow之构建自己的图片数据集TFrecords的方法

学习谷歌的深度学习终于有点眉目了，给大家分享我的Tensorflow学习历程。

tensorflow的官方中文文档比较生涩，数据集一直采用的MNIST二进制数据集。并没有过多讲述怎么构建自己的图片数据集tfrecords。

流程是：制作数据集—读取数据集—-加入队列

先贴完整的代码：

#encoding=utf-8
import os
import tensorflow as tf
from PIL import Image

cwd = os.getcwd()

classes = {'test','test1','test2'}
#制作二进制数据
def create_record():
  writer = tf.python_io.TFRecordWriter("train.tfrecords")
  for index, name in enumerate(classes):
    class_path = cwd +"/"+ name+"/"
    for img_name in os.listdir(class_path):
      img_path = class_path + img_name
      img = Image.open(img_path)
      img = img.resize((64, 64))
      img_raw = img.tobytes() #将图片转化为原生bytes
      print index,img_raw
      example = tf.train.Example(
        features=tf.train.Features(feature={
          "label": tf.train.Feature(int64_list=tf.train.Int64List(value=[index])),
          'img_raw': tf.train.Feature(bytes_list=tf.train.BytesList(value=[img_raw]))
        }))
      writer.write(example.SerializeToString())
  writer.close()

data = create_record()

#读取二进制数据
def read_and_decode(filename):
  # 创建文件队列,不限读取的数量
  filename_queue = tf.train.string_input_producer([filename])
  # create a reader from file queue
  reader = tf.TFRecordReader()
  # reader从文件队列中读入一个序列化的样本
  _, serialized_example = reader.read(filename_queue)
  # get feature from serialized example
  # 解析符号化的样本
  features = tf.parse_single_example(
    serialized_example,
    features={
      'label': tf.FixedLenFeature([], tf.int64),
      'img_raw': tf.FixedLenFeature([], tf.string)
    }
  )
  label = features['label']
  img = features['img_raw']
  img = tf.decode_raw(img, tf.uint8)
  img = tf.reshape(img, [64, 64, 3])
  img = tf.cast(img, tf.float32) * (1. / 255) - 0.5
  label = tf.cast(label, tf.int32)
  return img, label

if __name__ == '__main__':
  if 0:
    data = create_record("train.tfrecords")
  else:
    img, label = read_and_decode("train.tfrecords")
    print "tengxing",img,label
    #使用shuffle_batch可以随机打乱输入 next_batch挨着往下取
    # shuffle_batch才能实现[img,label]的同步,也即特征和label的同步,不然可能输入的特征和label不匹配
    # 比如只有这样使用,才能使img和label一一对应,每次提取一个image和对应的label
    # shuffle_batch返回的值就是RandomShuffleQueue.dequeue_many()的结果
    # Shuffle_batch构建了一个RandomShuffleQueue，并不断地把单个的[img,label],送入队列中
    img_batch, label_batch = tf.train.shuffle_batch([img, label],
                          batch_size=4, capacity=2000,
                          min_after_dequeue=1000)

    # 初始化所有的op
    init = tf.initialize_all_variables()

    with tf.Session() as sess:
      sess.run(init)
      # 启动队列
      threads = tf.train.start_queue_runners(sess=sess)
      for i in range(5):
        print img_batch.shape,label_batch
        val, l = sess.run([img_batch, label_batch])
        # l = to_categorical(l, 12)
        print(val.shape, l)

制作数据集

#制作二进制数据
def create_record():
  cwd = os.getcwd()
  classes = {'1','2','3'}
  writer = tf.python_io.TFRecordWriter("train.tfrecords")
  for index, name in enumerate(classes):
    class_path = cwd +"/"+ name+"/"
    for img_name in os.listdir(class_path):
      img_path = class_path + img_name
      img = Image.open(img_path)
      img = img.resize((28, 28))
      img_raw = img.tobytes() #将图片转化为原生bytes
      #print index,img_raw
      example = tf.train.Example(
        features=tf.train.Features(
          feature={
            "label": tf.train.Feature(int64_list=tf.train.Int64List(value=[index])),
            'img_raw': tf.train.Feature(bytes_list=tf.train.BytesList(value=[img_raw]))
          }
        )
      )
      writer.write(example.SerializeToString())
  writer.close()

TFRecords文件包含了tf.train.Example 协议内存块(protocol buffer)(协议内存块包含了字段 Features)。我们可以写一段代码获取你的数据， 将数据填入到Example协议内存块(protocol buffer)，将协议内存块序列化为一个字符串， 并且通过tf.python_io.TFRecordWriter 写入到TFRecords文件。

读取数据集

#读取二进制数据
def read_and_decode(filename):
  # 创建文件队列,不限读取的数量
  filename_queue = tf.train.string_input_producer([filename])
  # create a reader from file queue
  reader = tf.TFRecordReader()
  # reader从文件队列中读入一个序列化的样本
  _, serialized_example = reader.read(filename_queue)
  # get feature from serialized example
  # 解析符号化的样本
  features = tf.parse_single_example(
    serialized_example,
    features={
      'label': tf.FixedLenFeature([], tf.int64),
      'img_raw': tf.FixedLenFeature([], tf.string)
    }
  )
  label = features['label']
  img = features['img_raw']
  img = tf.decode_raw(img, tf.uint8)
  img = tf.reshape(img, [64, 64, 3])
  img = tf.cast(img, tf.float32) * (1. / 255) - 0.5
  label = tf.cast(label, tf.int32)
  return img, label

一个Example中包含Features，Features里包含Feature（这里没s）的字典。最后，Feature里包含有一个 FloatList， 或者ByteList，或者Int64List

加入队列

with tf.Session() as sess:
      sess.run(init)
      # 启动队列
      threads = tf.train.start_queue_runners(sess=sess)
      for i in range(5):
        print img_batch.shape,label_batch
        val, l = sess.run([img_batch, label_batch])
        # l = to_categorical(l, 12)
        print(val.shape, l)

这样就可以的到和tensorflow官方的二进制数据集了，

注意：

1. 启动队列那条code不要忘记，不然卡死
2. 使用的时候记得使用val和l，不然会报类型错误：TypeError: The value of a feed cannot be a tf.Tensor object. Acceptable feed values include Python scalars, strings, lists, or numpy ndarrays.
3. 算交叉熵时候：cross_entropy=tf.nn.sparse_softmax_cross_entropy_with_logits(logits,labels)算交叉熵
4. 最后评估的时候用tf.nn.in_top_k(logits,labels,1)选logits最大的数的索引和label比较
5. cross_entropy = -tf.reduce_sum(y_*tf.log(y_conv))算交叉熵，所以label必须转成one-hot向量

实例2：将图片文件夹下的图片转存tfrecords的数据集。

############################################################################################
#!/usr/bin/python2.7
# -*- coding: utf-8 -*-
#Author : zhaoqinghui
#Date  : 2016.5.10
#Function: image convert to tfrecords
############################################################################################# 

import tensorflow as tf
import numpy as np
import cv2
import os
import os.path
from PIL import Image 

#参数设置
###############################################################################################
train_file = 'train.txt' #训练图片
name='train'   #生成train.tfrecords
output_directory='./tfrecords'
resize_height=32 #存储图片高度
resize_width=32 #存储图片宽度
###############################################################################################
def _int64_feature(value):
  return tf.train.Feature(int64_list=tf.train.Int64List(value=[value])) 

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

def load_file(examples_list_file):
  lines = np.genfromtxt(examples_list_file, delimiter=" ", dtype=[('col1', 'S120'), ('col2', 'i8')])
  examples = []
  labels = []
  for example, label in lines:
    examples.append(example)
    labels.append(label)
  return np.asarray(examples), np.asarray(labels), len(lines) 

def extract_image(filename, resize_height, resize_width):
  image = cv2.imread(filename)
  image = cv2.resize(image, (resize_height, resize_width))
  b,g,r = cv2.split(image)
  rgb_image = cv2.merge([r,g,b])
  return rgb_image 

def transform2tfrecord(train_file, name, output_directory, resize_height, resize_width):
  if not os.path.exists(output_directory) or os.path.isfile(output_directory):
    os.makedirs(output_directory)
  _examples, _labels, examples_num = load_file(train_file)
  filename = output_directory + "/" + name + '.tfrecords'
  writer = tf.python_io.TFRecordWriter(filename)
  for i, [example, label] in enumerate(zip(_examples, _labels)):
    print('No.%d' % (i))
    image = extract_image(example, resize_height, resize_width)
    print('shape: %d, %d, %d, label: %d' % (image.shape[0], image.shape[1], image.shape[2], label))
    image_raw = image.tostring()
    example = tf.train.Example(features=tf.train.Features(feature={
      'image_raw': _bytes_feature(image_raw),
      'height': _int64_feature(image.shape[0]),
      'width': _int64_feature(image.shape[1]),
      'depth': _int64_feature(image.shape[2]),
      'label': _int64_feature(label)
    }))
    writer.write(example.SerializeToString())
  writer.close() 

def disp_tfrecords(tfrecord_list_file):
  filename_queue = tf.train.string_input_producer([tfrecord_list_file])
  reader = tf.TFRecordReader()
  _, serialized_example = reader.read(filename_queue)
  features = tf.parse_single_example(
    serialized_example,
 features={
     'image_raw': tf.FixedLenFeature([], tf.string),
     'height': tf.FixedLenFeature([], tf.int64),
     'width': tf.FixedLenFeature([], tf.int64),
     'depth': tf.FixedLenFeature([], tf.int64),
     'label': tf.FixedLenFeature([], tf.int64)
   }
  )
  image = tf.decode_raw(features['image_raw'], tf.uint8)
  #print(repr(image))
  height = features['height']
  width = features['width']
  depth = features['depth']
  label = tf.cast(features['label'], tf.int32)
  init_op = tf.initialize_all_variables()
  resultImg=[]
  resultLabel=[]
  with tf.Session() as sess:
    sess.run(init_op)
    coord = tf.train.Coordinator()
    threads = tf.train.start_queue_runners(sess=sess, coord=coord)
    for i in range(21):
      image_eval = image.eval()
      resultLabel.append(label.eval())
      image_eval_reshape = image_eval.reshape([height.eval(), width.eval(), depth.eval()])
      resultImg.append(image_eval_reshape)
      pilimg = Image.fromarray(np.asarray(image_eval_reshape))
      pilimg.show()
    coord.request_stop()
    coord.join(threads)
    sess.close()
  return resultImg,resultLabel 

def read_tfrecord(filename_queuetemp):
  filename_queue = tf.train.string_input_producer([filename_queuetemp])
  reader = tf.TFRecordReader()
  _, serialized_example = reader.read(filename_queue)
  features = tf.parse_single_example(
    serialized_example,
    features={
     'image_raw': tf.FixedLenFeature([], tf.string),
     'width': tf.FixedLenFeature([], tf.int64),
     'depth': tf.FixedLenFeature([], tf.int64),
     'label': tf.FixedLenFeature([], tf.int64)
   }
  )
  image = tf.decode_raw(features['image_raw'], tf.uint8)
  # image
  tf.reshape(image, [256, 256, 3])
  # normalize
  image = tf.cast(image, tf.float32) * (1. /255) - 0.5
  # label
  label = tf.cast(features['label'], tf.int32)
  return image, label 

def test():
  transform2tfrecord(train_file, name , output_directory, resize_height, resize_width) #转化函数
  img,label=disp_tfrecords(output_directory+'/'+name+'.tfrecords') #显示函数
  img,label=read_tfrecord(output_directory+'/'+name+'.tfrecords') #读取函数
  print label 

if __name__ == '__main__':
  test()

这样就可以得到自己专属的数据集.tfrecords了  ，它可以直接用于tensorflow的数据集。

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持我们。