python生成tensorflow输入输出的图像格式的方法

yipeiwu_com6年前Python基础

TensorFLow能够识别的图像文件,可以通过numpy,使用tf.Variable或者tf.placeholder加载进tensorflow;也可以通过自带函数(tf.read)读取,当图像文件过多时,一般使用pipeline通过队列的方法进行读取。下面我们介绍两种生成tensorflow的图像格式的方法,供给tensorflow的graph的输入与输出。

import cv2 
import numpy as np 
import h5py 
 
height = 460 
width = 345 
 
with h5py.File('make3d_dataset_f460.mat','r') as f: 
  images = f['images'][:] 
   
image_num = len(images) 
 
data = np.zeros((image_num, height, width, 3), np.uint8) 
data = images.transpose((0,3,2,1)) 

先生成图像文件的路径:ls *.jpg> list.txt

import cv2 
import numpy as np 
 
image_path = './' 
list_file = 'list.txt' 
height = 48 
width = 48 
 
image_name_list = [] # read image 
with open(image_path + list_file) as fid: 
  image_name_list = [x.strip() for x in fid.readlines()] 
image_num = len(image_name_list) 
 
data = np.zeros((image_num, height, width, 3), np.uint8) 
 
for idx in range(image_num): 
  img = cv2.imread(image_name_list[idx]) 
  img = cv2.resize(img, (height, width)) 
  data[idx, :, :, :] = img 

2 Tensorflow自带函数读取

def get_image(image_path): 
  """Reads the jpg image from image_path. 
  Returns the image as a tf.float32 tensor 
  Args: 
    image_path: tf.string tensor 
  Reuturn: 
    the decoded jpeg image casted to float32 
  """ 
  return tf.image.convert_image_dtype( 
    tf.image.decode_jpeg( 
      tf.read_file(image_path), channels=3), 
    dtype=tf.uint8) 

pipeline读取方法

# Example on how to use the tensorflow input pipelines. The explanation can be found here ischlag.github.io. 
import tensorflow as tf 
import random 
from tensorflow.python.framework import ops 
from tensorflow.python.framework import dtypes 
 
dataset_path   = "/path/to/your/dataset/mnist/" 
test_labels_file = "test-labels.csv" 
train_labels_file = "train-labels.csv" 
 
test_set_size = 5 
 
IMAGE_HEIGHT = 28 
IMAGE_WIDTH  = 28 
NUM_CHANNELS = 3 
BATCH_SIZE  = 5 
 
def encode_label(label): 
 return int(label) 
 
def read_label_file(file): 
 f = open(file, "r") 
 filepaths = [] 
 labels = [] 
 for line in f: 
  filepath, label = line.split(",") 
  filepaths.append(filepath) 
  labels.append(encode_label(label)) 
 return filepaths, labels 
 
# reading labels and file path 
train_filepaths, train_labels = read_label_file(dataset_path + train_labels_file) 
test_filepaths, test_labels = read_label_file(dataset_path + test_labels_file) 
 
# transform relative path into full path 
train_filepaths = [ dataset_path + fp for fp in train_filepaths] 
test_filepaths = [ dataset_path + fp for fp in test_filepaths] 
 
# for this example we will create or own test partition 
all_filepaths = train_filepaths + test_filepaths 
all_labels = train_labels + test_labels 
 
all_filepaths = all_filepaths[:20] 
all_labels = all_labels[:20] 
 
# convert string into tensors 
all_images = ops.convert_to_tensor(all_filepaths, dtype=dtypes.string) 
all_labels = ops.convert_to_tensor(all_labels, dtype=dtypes.int32) 
 
# create a partition vector 
partitions = [0] * len(all_filepaths) 
partitions[:test_set_size] = [1] * test_set_size 
random.shuffle(partitions) 
 
# partition our data into a test and train set according to our partition vector 
train_images, test_images = tf.dynamic_partition(all_images, partitions, 2) 
train_labels, test_labels = tf.dynamic_partition(all_labels, partitions, 2) 
 
# create input queues 
train_input_queue = tf.train.slice_input_producer( 
                  [train_images, train_labels], 
                  shuffle=False) 
test_input_queue = tf.train.slice_input_producer( 
                  [test_images, test_labels], 
                  shuffle=False) 
 
# process path and string tensor into an image and a label 
file_content = tf.read_file(train_input_queue[0]) 
train_image = tf.image.decode_jpeg(file_content, channels=NUM_CHANNELS) 
train_label = train_input_queue[1] 
 
file_content = tf.read_file(test_input_queue[0]) 
test_image = tf.image.decode_jpeg(file_content, channels=NUM_CHANNELS) 
test_label = test_input_queue[1] 
 
# define tensor shape 
train_image.set_shape([IMAGE_HEIGHT, IMAGE_WIDTH, NUM_CHANNELS]) 
test_image.set_shape([IMAGE_HEIGHT, IMAGE_WIDTH, NUM_CHANNELS]) 
 
 
# collect batches of images before processing 
train_image_batch, train_label_batch = tf.train.batch( 
                  [train_image, train_label], 
                  batch_size=BATCH_SIZE 
                  #,num_threads=1 
                  ) 
test_image_batch, test_label_batch = tf.train.batch( 
                  [test_image, test_label], 
                  batch_size=BATCH_SIZE 
                  #,num_threads=1 
                  ) 
 
print "input pipeline ready" 
 
with tf.Session() as sess: 
  
 # initialize the variables 
 sess.run(tf.initialize_all_variables()) 
  
 # initialize the queue threads to start to shovel data 
 coord = tf.train.Coordinator() 
 threads = tf.train.start_queue_runners(coord=coord) 
 
 print "from the train set:" 
 for i in range(20): 
  print sess.run(train_label_batch) 
 
 print "from the test set:" 
 for i in range(10): 
  print sess.run(test_label_batch) 
 
 # stop our queue threads and properly close the session 
 coord.request_stop() 
 coord.join(threads) 
 sess.close() 

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【听图阁-专注于Python设计】。

相关文章

基于python的多进程共享变量正确打开方式

多进程共享变量和获得结果 由于工程需求,要使用多线程来跑一个程序。但是因为听说python的多线程是假的,于是使用多进程,反正任务需要共享的参数少。 查阅资料,发现实现多进程主要使用Mu...

python使用reportlab画图示例(含中文汉字)

准备工作 开发环境:python2.6,reportlab 准备中文字体文件:simsun.ttc 代码: 复制代码 代码如下:#!/usr/bin/env python2.6#codi...

深入浅出分析Python装饰器用法

本文实例讲述了Python装饰器用法。分享给大家供大家参考,具体如下: 用类作为装饰器 示例一 最初代码: class bol(object): def __init__(self...

Django 对IP访问频率进行限制的例子

REST_FRAMEWORK 配置 对使用 rest_framework 框架的项目来说,可以使用框架的设置来对api的访问频率进行限制 REST_FRAMEWORK = {...

Python中xrange与yield的用法实例分析

本文实例分析了Python中xrange与yield的用法。分享给大家供大家参考,具体如下: range和xrange Python提供了生成和返回整数序列的内置函数range及xran...