基于TensorFlow的CNN实现Mnist手写数字识别详细,带有可视化界面,中文注释
时间: 2024-05-02 09:17:12 浏览: 129
基于TensorFlow的CNN实现Mnist手写数字识别
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以下是基于TensorFlow实现Mnist手写数字识别的详细步骤,包括可视化界面和中文注释。
1. 导入必要的包
```python
import tensorflow as tf
from tensorflow.examples.tutorials.mnist import input_data
import matplotlib.pyplot as plt
import numpy as np
```
2. 加载数据集
```python
mnist = input_data.read_data_sets('MNIST_data', one_hot=True)
```
3. 定义占位符
```python
x = tf.placeholder(tf.float32, [None, 784])
y = tf.placeholder(tf.float32, [None, 10])
```
4. 初始化权重和偏置
```python
def weight_variable(shape):
initial = tf.truncated_normal(shape, stddev=0.1)
return tf.Variable(initial)
def bias_variable(shape):
initial = tf.constant(0.1, shape=shape)
return tf.Variable(initial)
```
5. 定义卷积和池化操作
```python
def conv2d(x, W):
return tf.nn.conv2d(x, W, strides=[1, 1, 1, 1], padding='SAME')
def max_pool_2x2(x):
return tf.nn.max_pool(x, ksize=[1, 2, 2, 1],
strides=[1, 2, 2, 1], padding='SAME')
```
6. 构建卷积神经网络模型
```python
x_image = tf.reshape(x, [-1,28,28,1])
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)
h_pool1 = max_pool_2x2(h_conv1)
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)
h_pool2 = max_pool_2x2(h_conv2)
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)
keep_prob = tf.placeholder(tf.float32)
h_fc1_drop = tf.nn.dropout(h_fc1, keep_prob)
W_fc2 = weight_variable([1024, 10])
b_fc2 = bias_variable([10])
y_conv = tf.matmul(h_fc1_drop, W_fc2) + b_fc2
```
7. 定义损失函数和优化器
```python
cross_entropy = tf.reduce_mean(
tf.nn.softmax_cross_entropy_with_logits(labels=y, logits=y_conv))
train_step = tf.train.AdamOptimizer(1e-4).minimize(cross_entropy)
```
8. 定义评估准确率的操作
```python
correct_prediction = tf.equal(tf.argmax(y_conv, 1), tf.argmax(y, 1))
accuracy = tf.reduce_mean(tf.cast(correct_prediction, tf.float32))
```
9. 运行训练过程
```python
sess = tf.InteractiveSession()
sess.run(tf.global_variables_initializer())
for i in range(20000):
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}))
```
10. 可视化卷积层的输出结果
```python
def plot_conv_layer(layer, image):
feed_dict = {x: [image], keep_prob: 1.0}
values = sess.run(layer, feed_dict=feed_dict)
num_filters = values.shape[3]
fig, axes = plt.subplots(1, num_filters)
for i, ax in enumerate(axes.flat):
img = values[0, :, :, i]
ax.imshow(img, interpolation='nearest', cmap='binary')
ax.set_xticks([])
ax.set_yticks([])
plt.show()
image = mnist.test.images[0]
plot_conv_layer(h_conv1, image)
```
以上就是基于TensorFlow实现Mnist手写数字识别的详细步骤,包括可视化界面和中文注释。
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