# -*- coding: utf-8 -*-
"""
Created on Tue May 14 14:11:47 2019
@author: user
"""
#========================================================================
#输入数据:(batch_size,IMG_W,IMG_H,col_channel)= (20, 64, 64, 3)
#
#卷积层1: (conv_kernel,num_channel,num_out_neure)= (3, 3, 3, 64)
#
#池化层1: (ksize,strides,padding)= ([1,3,3,1], [1,2,2,1], 'SAME')
#
#卷积层2: (conv_kernel,num_channel,num_out_neure)= (3, 3, 64, 16)
#
#池化层2: (ksize,strides,padding)= ([1,3,3,1], [1,1,1,1], 'SAME')
#
#全连接1: (out_pool2_reshape,num_out_neure)= (dim, 128)
#
#全连接2: (fc1_out,num_out_neure)= (128,128)
#
#softmax层: (fc2_out,num_classes) = (128, 4)
#
#激活函数: tf.nn.relu
#
#损失函数: tf.nn.sparse_softmax_cross_entropy_with_logits
#---------------------
#=========================================================================
import tensorflow as tf
#=========================================================================
#网络结构定义
#输入参数:images,image batch、4D tensor、tf.float32、[batch_size, width, height, channels]
#返回参数:logits, float、 [batch_size, n_classes]
def inference(images, batch_size, n_classes):
#一个简单的卷积神经网络,卷积+池化层x2,全连接层x2,最后一个softmax层做分类。
#卷积层1
#64个3x3的卷积核(3通道),padding=’SAME’,表示padding后卷积的图与原图尺寸一致,激活函数relu()
with tf.variable_scope('conv1') as scope:
weights = tf.Variable(tf.truncated_normal(shape=[3,3,3,64], stddev = 1.0, dtype = tf.float32),
name = 'weights', dtype = tf.float32)
biases = tf.Variable(tf.constant(value = 0.1, dtype = tf.float32, shape = [64]),
name = 'biases', dtype = tf.float32)
conv = tf.nn.conv2d(images, weights, strides=[1,1,1,1], padding='SAME')
pre_activation = tf.nn.bias_add(conv, biases)
conv1 = tf.nn.relu(pre_activation, name= scope.name)
#池化层1
#3x3最大池化,步长strides为2,池化后执行lrn()操作,局部响应归一化,对训练有利。
with tf.variable_scope('pooling1_lrn') as scope:
pool1 = tf.nn.max_pool(conv1, ksize=[1,3,3,1],strides=[1,2,2,1],padding='SAME', name='pooling1')
norm1 = tf.nn.lrn(pool1, depth_radius=4, bias=1.0, alpha=0.001/9.0, beta=0.75, name='norm1')
#卷积层2
#16个3x3的卷积核(16通道),padding=’SAME’,表示padding后卷积的图与原图尺寸一致,激活函数relu()
with tf.variable_scope('conv2') as scope:
weights = tf.Variable(tf.truncated_normal(shape=[3,3,64,16], stddev = 0.1, dtype = tf.float32),
name = 'weights', dtype = tf.float32)
biases = tf.Variable(tf.constant(value = 0.1, dtype = tf.float32, shape = [16]),
name = 'biases', dtype = tf.float32)
conv = tf.nn.conv2d(norm1, weights, strides = [1,1,1,1],padding='SAME')
pre_activation = tf.nn.bias_add(conv, biases)
conv2 = tf.nn.relu(pre_activation, name='conv2')
#池化层2
#3x3最大池化,步长strides为2,池化后执行lrn()操作,
#pool2 and norm2
with tf.variable_scope('pooling2_lrn') as scope:
norm2 = tf.nn.lrn(conv2, depth_radius=4, bias=1.0, alpha=0.001/9.0,beta=0.75,name='norm2')
pool2 = tf.nn.max_pool(norm2, ksize=[1,3,3,1], strides=[1,1,1,1],padding='SAME',name='pooling2')
#全连接层3
#128个神经元,将之前pool层的输出reshape成一行,激活函数relu()
with tf.variable_scope('local3') as scope:
reshape = tf.reshape(pool2, shape=[batch_size, -1])
dim = reshape.get_shape()[1].value
weights = tf.Variable(tf.truncated_normal(shape=[dim,128], stddev = 0.005, dtype = tf.float32),
name = 'weights', dtype = tf.float32)
biases = tf.Variable(tf.constant(value = 0.1, dtype = tf.float32, shape = [128]),
name = 'biases', dtype=tf.float32)
local3 = tf.nn.relu(tf.matmul(reshape, weights) + biases, name=scope.name)
#全连接层4
#128个神经元,激活函数relu()
with tf.variable_scope('local4') as scope:
weights = tf.Variable(tf.truncated_normal(shape=[128,128], stddev = 0.005, dtype = tf.float32),
name = 'weights',dtype = tf.float32)
biases = tf.Variable(tf.constant(value = 0.1, dtype = tf.float32, shape = [128]),
name = 'biases', dtype = tf.float32)
local4 = tf.nn.relu(tf.matmul(local3, weights) + biases, name='local4')
#dropout层
# with tf.variable_scope('dropout') as scope:
# drop_out = tf.nn.dropout(local4, 0.8)
#Softmax回归层
#将前面的FC层输出,做一个线性回归,计算出每一类的得分,在这里是2类,所以这个层输出的是两个得分。
with tf.variable_scope('softmax_linear') as scope:
weights = tf.Variable(tf.truncated_normal(shape=[128, n_classes], stddev = 0.005, dtype = tf.float32),
name = 'softmax_linear', dtype = tf.float32)
biases = tf.Variable(tf.constant(value = 0.1, dtype = tf.float32, shape = [n_classes]),
name = 'biases', dtype = tf.float32)
softmax_linear = tf.add(tf.matmul(local4, weights), biases, name='softmax_linear')
return softmax_linear
#-----------------------------------------------------------------------------
#loss计算
#传入参数:logits,网络计算输出值。labels,真实值,在这里是0或者1
#返回参数:loss,损失值
def losses(logits, labels):
with tf.variable_scope('loss') as scope:
cross_entropy =tf.nn.sparse_softmax_cross_entropy_with_logits(logits=logits, labels=labels, name='xentropy_per_example')
loss = tf.reduce_mean(cross_entropy, name='loss')
tf.summary.scalar(scope.name+'/loss', loss)
return loss
#--------------------------------------------------------------------------
#loss损失值优化
#输入参数:loss。learning_rate,学习速率。
#返回参数:train_op,训练op,这个参数要输入sess.run中让模型去训练。
def trainning(loss, learning_rate):
with tf.name_scope('optimizer'):
optimizer = tf.train.AdamOptimizer(learning_rate= learning_rate)
global_step = tf.Variable(0, name='global_step', trainable=False)
train_op = optimizer.minimize(loss, global_step= global_step)
return train_op
#-----------------------------------------------------------------------
#评价/准确率计算
#输入参数:logits,网络计算值。labels,标签,也就是真实值,在这里是0或者1。
#返回参数:accuracy,当前step的平均准确率,也就是在这些batch中多少张图片被正确分类了。
def evaluation(logits, labels):
with tf.variable_scope('accuracy') as scope:
correct = tf.nn.in_top_k(logits, labels, 1)
correct = tf.cast(correct, tf.float16)
accuracy = tf.reduce_mean(correct)
tf.summary.scalar(scope.name+'/accuracy', accuracy)
return accuracy
#========================================================================