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tensorflow 20如何搭網(wǎng)絡(luò),導(dǎo)出模型和運行模型

發(fā)布時間:2020-07-22 09:52:38 來源:億速云 閱讀:159 作者:小豬 欄目:開發(fā)技術(shù)

這篇文章主要為大家展示了tensorflow 20如何搭網(wǎng)絡(luò),導(dǎo)出模型和運行模型,內(nèi)容簡而易懂,希望大家可以學(xué)習(xí)一下,學(xué)習(xí)完之后肯定會有收獲的,下面讓小編帶大家一起來看看吧。

概述

以前自己都利用別人搭好的工程,修改過來用,很少把模型搭建、導(dǎo)出模型、加載模型運行走一遍,搞了一遍才知道這個事情也不是那么簡單的。

搭建模型和導(dǎo)出模型

參考《TensorFlow固化模型》,導(dǎo)出固化的模型有兩種方式.

方式1:導(dǎo)出pb圖結(jié)構(gòu)和ckpt文件,然后用 freeze_graph 工具凍結(jié)生成一個pb(包含結(jié)構(gòu)和參數(shù))

在我的代碼里測試了生成pb圖結(jié)構(gòu)和ckpt文件,但是沒接著往下走,感覺有點麻煩。我用的是第二種方法。

注意我這里只在最后保存了一次ckpt,實際應(yīng)該在訓(xùn)練中每隔一段時間就保存一次的。

 saver = tf.train.Saver(max_to_keep=5)
 #tf.train.write_graph(session.graph_def, FLAGS.model_dir, "nn_model.pbtxt", as_text=True)
 
 with tf.Session() as sess:
 sess.run(tf.global_variables_initializer())

 max_step = 2000
 for i in range(max_step):
 batch = mnist.train.next_batch(50)
 if i % 100 == 0:
 train_accuracy = accuracy.eval(feed_dict={
  x: batch[0], y_: batch[1], keep_prob: 1.0})
 print('step %d, training accuracy %g' % (i, train_accuracy))
 train_step.run(feed_dict={x: batch[0], y_: batch[1], keep_prob: 0.5})
 
 print('test accuracy %g' % accuracy.eval(feed_dict={
 x: mnist.test.images, y_: mnist.test.labels, keep_prob: 1.0}))
 
 # 保存pb和ckpt
 print('save pb file and ckpt file')
 tf.train.write_graph(sess.graph_def, graph_location, "graph.pb",as_text=False)
 checkpoint_path = os.path.join(graph_location, "model.ckpt")
 saver.save(sess, checkpoint_path, global_step=max_step)

方式2:convert_variables_to_constants

我實際使用的就是這種方法。

看名字也知道,就是把變量轉(zhuǎn)化為常量保存,這樣就可以愉快的加載使用了。

注意這里需要指明保存的輸出節(jié)點,我的輸出節(jié)點為'out/fc2'(我猜測會根據(jù)輸出節(jié)點的依賴推斷哪些部分是訓(xùn)練用到的,推理時用不到)。關(guān)于輸出節(jié)點的名字是有規(guī)律的,其中out是一個name_scope名字,fc2是op節(jié)點的名字。

 with tf.Session() as sess:
 sess.run(tf.global_variables_initializer())

 max_step = 2000
 for i in range(max_step):
 batch = mnist.train.next_batch(50)
 if i % 100 == 0:
 train_accuracy = accuracy.eval(feed_dict={
  x: batch[0], y_: batch[1], keep_prob: 1.0})
 print('step %d, training accuracy %g' % (i, train_accuracy))
 train_step.run(feed_dict={x: batch[0], y_: batch[1], keep_prob: 0.5})
 
 print('test accuracy %g' % accuracy.eval(feed_dict={
 x: mnist.test.images, y_: mnist.test.labels, keep_prob: 1.0}))

 print('save frozen file')
 pb_path = os.path.join(graph_location, 'frozen_graph.pb')
 print('pb_path:{}'.format(pb_path))

 # 固化模型
 output_graph_def = convert_variables_to_constants(sess, sess.graph_def, output_node_names=['out/fc2'])
 with tf.gfile.FastGFile(pb_path, mode='wb') as f:
 f.write(output_graph_def.SerializeToString())

上述代碼會在訓(xùn)練后把訓(xùn)練好的計算圖和參數(shù)保存到frozen_graph.pb文件。后續(xù)就可以用這個模型來測試圖片了。

方式2的完整訓(xùn)練和保存模型代碼

主要看main函數(shù)就行。另外注意deepnn函數(shù)最后節(jié)點的名字。

"""A deep MNIST classifier using convolutional layers.

See extensive documentation at
https://www.tensorflow.org/get_started/mnist/pros
"""
# Disable linter warnings to maintain consistency with tutorial.
# pylint: disable=invalid-name
# pylint: disable=g-bad-import-order

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

import argparse
import sys
import tempfile
import os

from tensorflow.examples.tutorials.mnist import input_data
from tensorflow.python.framework.graph_util import convert_variables_to_constants

import tensorflow as tf
FLAGS = None

def deepnn(x):
 """deepnn builds the graph for a deep net for classifying digits.

 Args:
 x: an input tensor with the dimensions (N_examples, 784), where 784 is the
 number of pixels in a standard MNIST image.

 Returns:
 A tuple (y, keep_prob). y is a tensor of shape (N_examples, 10), with values
 equal to the logits of classifying the digit into one of 10 classes (the
 digits 0-9). keep_prob is a scalar placeholder for the probability of
 dropout.
 """
 # Reshape to use within a convolutional neural net.
 # Last dimension is for "features" - there is only one here, since images are
 # grayscale -- it would be 3 for an RGB image, 4 for RGBA, etc.
 with tf.name_scope('reshape'):
 x_image = tf.reshape(x, [-1, 28, 28, 1])

 # First convolutional layer - maps one grayscale image to 32 feature maps.
 with tf.name_scope('conv1'):
 W_conv1 = weight_variable([5, 5, 1, 32])
 b_conv1 = bias_variable([32])
 h_conv1 = tf.nn.relu(conv2d(x_image, W_conv1) + b_conv1)

 # Pooling layer - downsamples by 2X.
 with tf.name_scope('pool1'):
 h_pool1 = max_pool_2x2(h_conv1)

 # Second convolutional layer -- maps 32 feature maps to 64.
 with tf.name_scope('conv2'):
 W_conv2 = weight_variable([5, 5, 32, 64])
 b_conv2 = bias_variable([64])
 h_conv2 = tf.nn.relu(conv2d(h_pool1, W_conv2) + b_conv2)

 # Second pooling layer.
 with tf.name_scope('pool2'):
 h_pool2 = max_pool_2x2(h_conv2)

 # Fully connected layer 1 -- after 2 round of downsampling, our 28x28 image
 # is down to 7x7x64 feature maps -- maps this to 1024 features.
 with tf.name_scope('fc1'):
 W_fc1 = weight_variable([7 * 7 * 64, 1024])
 b_fc1 = bias_variable([1024])

 h_pool2_flat = tf.reshape(h_pool2, [-1, 7 * 7 * 64])
 h_fc1 = tf.nn.relu(tf.matmul(h_pool2_flat, W_fc1) + b_fc1)

 # Dropout - controls the complexity of the model, prevents co-adaptation of
 # features.
 with tf.name_scope('dropout'):
 keep_prob = tf.placeholder(tf.float32, name='ratio')
 h_fc1_drop = tf.nn.dropout(h_fc1, keep_prob)

 # Map the 1024 features to 10 classes, one for each digit
 with tf.name_scope('out'):
 W_fc2 = weight_variable([1024, 10])
 b_fc2 = bias_variable([10])

 y_conv = tf.add(tf.matmul(h_fc1_drop, W_fc2), b_fc2, name='fc2')
 return y_conv, keep_prob

def conv2d(x, W):
 """conv2d returns a 2d convolution layer with full stride."""
 return tf.nn.conv2d(x, W, strides=[1, 1, 1, 1], padding='SAME')

def max_pool_2x2(x):
 """max_pool_2x2 downsamples a feature map by 2X."""
 return tf.nn.max_pool(x, ksize=[1, 2, 2, 1],
   strides=[1, 2, 2, 1], padding='SAME')

def weight_variable(shape):
 """weight_variable generates a weight variable of a given shape."""
 initial = tf.truncated_normal(shape, stddev=0.1)
 return tf.Variable(initial)

def bias_variable(shape):
 """bias_variable generates a bias variable of a given shape."""
 initial = tf.constant(0.1, shape=shape)
 return tf.Variable(initial)

def main(_):
 # Import data
 mnist = input_data.read_data_sets(FLAGS.data_dir)

 # Create the model
 with tf.name_scope('input'):
 x = tf.placeholder(tf.float32, [None, 784], name='x')

 # Define loss and optimizer
 y_ = tf.placeholder(tf.int64, [None])

 # Build the graph for the deep net
 y_conv, keep_prob = deepnn(x)

 with tf.name_scope('loss'):
 cross_entropy = tf.losses.sparse_softmax_cross_entropy(
 labels=y_, logits=y_conv)
 cross_entropy = tf.reduce_mean(cross_entropy)

 with tf.name_scope('adam_optimizer'):
 train_step = tf.train.AdamOptimizer(1e-4).minimize(cross_entropy)

 with tf.name_scope('accuracy'):
 correct_prediction = tf.equal(tf.argmax(y_conv, 1), y_)
 correct_prediction = tf.cast(correct_prediction, tf.float32)
 accuracy = tf.reduce_mean(correct_prediction)

 graph_location = './model'
 print('Saving graph to: %s' % graph_location)
 train_writer = tf.summary.FileWriter(graph_location)
 train_writer.add_graph(tf.get_default_graph())

 saver = tf.train.Saver(max_to_keep=5)
 #tf.train.write_graph(session.graph_def, FLAGS.model_dir, "nn_model.pbtxt", as_text=True)
 
 with tf.Session() as sess:
 sess.run(tf.global_variables_initializer())

 max_step = 2000
 for i in range(max_step):
 batch = mnist.train.next_batch(50)
 if i % 100 == 0:
 train_accuracy = accuracy.eval(feed_dict={
  x: batch[0], y_: batch[1], keep_prob: 1.0})
 print('step %d, training accuracy %g' % (i, train_accuracy))
 train_step.run(feed_dict={x: batch[0], y_: batch[1], keep_prob: 0.5})
 
 print('test accuracy %g' % accuracy.eval(feed_dict={
 x: mnist.test.images, y_: mnist.test.labels, keep_prob: 1.0}))
 
 # save pb file and ckpt file
 #print('save pb file and ckpt file')
 #tf.train.write_graph(sess.graph_def, graph_location, "graph.pb", as_text=False)
 #checkpoint_path = os.path.join(graph_location, "model.ckpt")
 #saver.save(sess, checkpoint_path, global_step=max_step)

 print('save frozen file')
 pb_path = os.path.join(graph_location, 'frozen_graph.pb')
 print('pb_path:{}'.format(pb_path))

 output_graph_def = convert_variables_to_constants(sess, sess.graph_def, output_node_names=['out/fc2'])
 with tf.gfile.FastGFile(pb_path, mode='wb') as f:
 f.write(output_graph_def.SerializeToString())

if __name__ == '__main__':
 parser = argparse.ArgumentParser()
 parser.add_argument('--data_dir', type=str,
   default='./data',
   help='Directory for storing input data')
 FLAGS, unparsed = parser.parse_known_args()
 tf.app.run(main=main, argv=[sys.argv[0]] + unparsed) 

加載模型進行推理

上一節(jié)已經(jīng)訓(xùn)練并導(dǎo)出了frozen_graph.pb。

這一節(jié)把它運行起來。

加載模型

下方的代碼用來加載模型。推理時計算圖里共兩個placeholder需要填充數(shù)據(jù),一個是圖片(這不廢話嗎),一個是drouout_ratio,drouout_ratio用一個常量作為輸入,后續(xù)就只需要輸入圖片了。

graph_location = './model'
pb_path = os.path.join(graph_location, 'frozen_graph.pb')
print('pb_path:{}'.format(pb_path))

newInput_X = tf.placeholder(tf.float32, [None, 784], name="X")
drouout_ratio = tf.constant(1., name="drouout")
with open(pb_path, 'rb') as f:
 graph_def = tf.GraphDef()
 graph_def.ParseFromString(f.read())

 output = tf.import_graph_def(graph_def,
     input_map={'input/x:0': newInput_X, 'dropout/ratio:0':drouout_ratio},
     return_elements=['out/fc2:0'])

input_map參數(shù)并不是必須的。如果不用input_map,可以在run之前用tf.get_default_graph().get_tensor_by_name獲取tensor的句柄。但是我覺得這種方法不是很友好,我這里沒用這種方法。

注意input_map里的tensor名字是和搭計算圖時的name_scope和op名字有關(guān)的,而且后面要補一個‘:0'(這點我還沒細究)。

同時要注意,newInput_X的形狀是[None, 784],第一維是batch大小,推理時和訓(xùn)練要一致。

(我用的是mnist圖片,訓(xùn)練時每個bacth的形狀是[batchsize, 784],每個圖片是28x28)

運行模型

我是一張張圖片單獨測試的,運行模型之前先把圖片變?yōu)閇1, 784],以符合newInput_X的維數(shù)。

with tf.Session( ) as sess:
 file_list = os.listdir(test_image_dir)
 
 # 遍歷文件
 for file in file_list:
 full_path = os.path.join(test_image_dir, file)
 print('full_path:{}'.format(full_path))
 
 # 只要黑白的,大小控制在(28,28)
 img = cv2.imread(full_path, cv2.IMREAD_GRAYSCALE )
 res_img = cv2.resize(img,(28,28),interpolation=cv2.INTER_CUBIC) 
 # 變成長784的一維數(shù)據(jù)
 new_img = res_img.reshape((784))
 
 # 增加一個維度,變?yōu)?[1, 784]
 image_np_expanded = np.expand_dims(new_img, axis=0)
 image_np_expanded.astype('float32') # 類型也要滿足要求
 print('image_np_expanded shape:{}'.format(image_np_expanded.shape))
 
 # 注意注意,我要調(diào)用模型了
 result = sess.run(output, feed_dict={newInput_X: image_np_expanded})
 
 # 出來的結(jié)果去掉沒用的維度
 result = np.squeeze(result)
 print('result:{}'.format(result))
 #print('result:{}'.format(sess.run(output, feed_dict={newInput_X: image_np_expanded})))
 
 # 輸出結(jié)果是長度為10(對應(yīng)0-9)的一維數(shù)據(jù),最大值的下標就是預(yù)測的數(shù)字
 print('result:{}'.format( (np.where(result==np.max(result)))[0][0] ))

注意模型的輸出是一個長度為10的一維數(shù)組,也就是計算圖里全連接的輸出。這里沒有softmax,只要取最大值的下標即可得到結(jié)果。

輸出結(jié)果:

full_path:./test_images/97_7.jpg
image_np_expanded shape:(1, 784)
result:[-1340.37145996 -283.72436523 1305.03320312 437.6053772 -413.69961548
 -1218.08166504 -1004.83807373 1953.33984375 42.00457001 -504.43829346]
result:7

full_path:./test_images/98_6.jpg
image_np_expanded shape:(1, 784)
result:[ 567.4041748 -550.20904541 623.83496094 -1152.56884766 -217.92695618
 1033.45239258 2496.44750977 -1139.23620605 -5.64091825 -615.28491211]
result:6

full_path:./test_images/99_9.jpg
image_np_expanded shape:(1, 784)
result:[ -532.26409912 -1429.47277832 -368.58096313 505.82876587 358.42163086
 -317.48199463 -1108.6829834 1198.08752441 289.12286377 3083.52539062]
result:9

加載模型進行推理的完整代碼

import sys
import os
import cv2
import numpy as np
import tensorflow as tf
test_image_dir = './test_images/'

graph_location = './model'
pb_path = os.path.join(graph_location, 'frozen_graph.pb')
print('pb_path:{}'.format(pb_path))

newInput_X = tf.placeholder(tf.float32, [None, 784], name="X")
drouout_ratio = tf.constant(1., name="drouout")
with open(pb_path, 'rb') as f:
 graph_def = tf.GraphDef()
 graph_def.ParseFromString(f.read())
 #output = tf.import_graph_def(graph_def)
 output = tf.import_graph_def(graph_def,
     input_map={'input/x:0': newInput_X, 'dropout/ratio:0':drouout_ratio},
     return_elements=['out/fc2:0'])

with tf.Session( ) as sess:
 file_list = os.listdir(test_image_dir)
 
 # 遍歷文件
 for file in file_list:
 full_path = os.path.join(test_image_dir, file)
 print('full_path:{}'.format(full_path))
 
 # 只要黑白的,大小控制在(28,28)
 img = cv2.imread(full_path, cv2.IMREAD_GRAYSCALE )
 res_img = cv2.resize(img,(28,28),interpolation=cv2.INTER_CUBIC) 
 # 變成長784的一維數(shù)據(jù)
 new_img = res_img.reshape((784))
 
 # 增加一個維度,變?yōu)?[1, 784]
 image_np_expanded = np.expand_dims(new_img, axis=0)
 image_np_expanded.astype('float32') # 類型也要滿足要求
 print('image_np_expanded shape:{}'.format(image_np_expanded.shape))
 
 # 注意注意,我要調(diào)用模型了
 result = sess.run(output, feed_dict={newInput_X: image_np_expanded})
 
 # 出來的結(jié)果去掉沒用的維度
 result = np.squeeze(result)
 print('result:{}'.format(result))
 #print('result:{}'.format(sess.run(output, feed_dict={newInput_X: image_np_expanded})))
 
 # 輸出結(jié)果是長度為10(對應(yīng)0-9)的一維數(shù)據(jù),最大值的下標就是預(yù)測的數(shù)字
 print('result:{}'.format( (np.where(result==np.max(result)))[0][0] )) 

以上就是關(guān)于tensorflow 20如何搭網(wǎng)絡(luò),導(dǎo)出模型和運行模型的內(nèi)容,如果你們有學(xué)習(xí)到知識或者技能,可以把它分享出去讓更多的人看到。

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