浅谈TensorFlow中读取图像数据的三种方式

import tensorflow as tf
import matplotlib.pyplot as plt

def read_image(file_name):
 img = tf.read_file(filename=file_name)  # 默认读取格式为uint8
 print("img 的类型是",type(img));
 img = tf.image.decode_jpeg(img,channels=0) # channels 为1得到的是灰度图，为0则按照图片格式来读
 return img

def main( ):
 with tf.device("/cpu:0"):
　　　　  # img_path是文件所在地址包括文件名称，地址用相对地址或者绝对地址都行 
   img_path='./1.jpg'
   img=read_image(img_path)
   with tf.Session() as sess:
   image_numpy=sess.run(img)
   print(image_numpy)
   print(image_numpy.dtype)
   print(image_numpy.shape)
   plt.imshow(image_numpy)
   plt.show()

if __name__=="__main__":
 main()

"""

def get_image_batch(data_file,batch_size):
 data_names=[os.path.join(data_file,k) for k in os.listdir(data_file)]
 
 #这个num_epochs函数在整个Graph是local Variable，所以在sess.run全局变量的时候也要加上局部变量。 
 filenames_queue=tf.train.string_input_producer(data_names,num_epochs=50,shuffle=True,capacity=512)
 reader=tf.WholeFileReader()
 _,img_bytes=reader.read(filenames_queue)
 image=tf.image.decode_png(img_bytes,channels=1) #读取的是什么格式，就decode什么格式
 #解码成单通道的，并且获得的结果的shape是[?, ?,1]，也就是Graph不知道图像的大小，需要set_shape
 image.set_shape([180,180,1]) #set到原本已知图像的大小。或者直接通过tf.image.resize_images，tf.reshape()
 image=tf.image.convert_image_dtype(image,tf.float32)
 #预处理 下面的一句代码可以换成自己想使用的预处理方式
 #image=tf.divide(image,255.0) 
 return tf.train.batch([image],batch_size) 

import tensorflow as tf
import os
def read_image(data_file,batch_size):
 data_names=[os.path.join(data_file,k) for k in os.listdir(data_file)]
 filenames_queue=tf.train.string_input_producer(data_names,num_epochs=5,shuffle=True,capacity=30)
 reader=tf.WholeFileReader()
 _,img_bytes=reader.read(filenames_queue)
 image=tf.image.decode_jpeg(img_bytes,channels=1)
 image=tf.image.resize_images(image,(180,180))

 image=tf.image.convert_image_dtype(image,tf.float32)
 return tf.train.batch([image],batch_size)

def main( ):
 img_path=r'F:\dataSet\WIDER\WIDER_train\images\6--Funeral' #本地的一个数据集目录，有足够的图像
 img=read_image(img_path,batch_size=10)
 image=img[0] #取出每个batch的第一个数据
 print(image)
 init=[tf.global_variables_initializer(),tf.local_variables_initializer()]
 with tf.Session() as sess:
  sess.run(init)
  coord = tf.train.Coordinator()
  threads = tf.train.start_queue_runners(sess=sess,coord=coord)
  try:
   while not coord.should_stop():
    print(image.shape)
  except tf.errors.OutOfRangeError:
   print('read done')
  finally:
   coord.request_stop()
  coord.join(threads)


if __name__=="__main__":
 main()

"""

import tensorflow as tf
import matplotlib.pyplot as plt
import os
import cv2
import numpy as np
import glob

def read_image(data_file,batch_size):
 files_path=glob.glob(data_file)
 queue=tf.train.string_input_producer(files_path,num_epochs=None)
 reader = tf.TFRecordReader()
 print(queue)
 _, serialized_example = reader.read(queue)
 features = tf.parse_single_example(
  serialized_example,
  features={
   'image_raw': tf.FixedLenFeature([], tf.string),
   'label_raw': tf.FixedLenFeature([], tf.string),
  })
 image = tf.decode_raw(features['image_raw'], tf.uint8)
 image = tf.cast(image, tf.float32)
 image.set_shape((12*12*3))
 label = tf.decode_raw(features['label_raw'], tf.float32)
 label.set_shape((2))
 # 预处理部分省略，大家可以自己根据需要添加
 return tf.train.batch([image,label],batch_size=batch_size,num_threads=4,capacity=5*batch_size)

def main( ):
 img_path=r'F:\python\MTCNN_by_myself\prepare_data\pnet*.tfrecords' #本地的几个tf文件
 img,label=read_image(img_path,batch_size=10)
 image=img[0]
 init=[tf.global_variables_initializer(),tf.local_variables_initializer()]
 with tf.Session() as sess:
  sess.run(init)
  coord = tf.train.Coordinator()
  threads = tf.train.start_queue_runners(sess=sess,coord=coord)
  try:
   while not coord.should_stop():
    print(image.shape)
  except tf.errors.OutOfRangeError:
   print('read done')
  finally:
   coord.request_stop()
  coord.join(threads)


if __name__=="__main__":
 main()

reader=tf.TFRecordReader()
_,serialized_example=reader.read(file_name_queue)
features = tf.parse_single_example(serialized_example, features={
 'data': tf.FixedLenFeature([256,256], tf.float32), ###
 'label': tf.FixedLenFeature([], tf.int64),
 'id': tf.FixedLenFeature([], tf.int64)
})
img = features['data']
label =features['label']
id = features['id']