【转】Tensorflow应用之简单验证码识别

2020-12-18 15:00:35 编辑 1 阅读量:777

# 1.Tensorflow的安装方式简单,在此就不赘述了.

# 2.训练集训练集以及测试及如下(纯手工打造,所以数量不多):

![训练集](http://img.blog.csdn.net/20170518194813486?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvaHVwbGlvbg==/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast "训练集")
![测试集](http://img.blog.csdn.net/20170518194930674?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvaHVwbGlvbg==/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast "测试集")

# 3.实现代码部分(参考了网上的一些实现来完成的)

#### main.py(主要的神经网络代码)

```
from gen_check_code import gen_captcha_text_and_image_new,gen_captcha_text_and_image
from gen_check_code import number
from test_check_code import get_test_captcha_text_and_image
import numpy as np
import tensorflow as tf

text, image = gen_captcha_text_and_image_new()
print("验证码图像channel:", image.shape)  # (60, 160, 3)  
# 图像大小  
IMAGE_HEIGHT = image.shape[0]
IMAGE_WIDTH = image.shape[1]
image_shape = image.shape
MAX_CAPTCHA = len(text)
print("验证码文本最长字符数", MAX_CAPTCHA)  # 验证码最长4字符; 我全部固定为4,可以不固定. 如果验证码长度小于4，用'_'补齐

# 把彩色图像转为灰度图像（色彩对识别验证码没有什么用）
# 度化是将三分量转化成一样数值的过程
def convert2gray(img):
    if len(img.shape) > 2:
        gray = np.mean(img, -1)
        # 上面的转法较快，正规转法如下  
        # r, g, b = img[:,:,0], img[:,:,1], img[:,:,2]  
        # gray = 0.2989 * r + 0.5870 * g + 0.1140 * b
        # int gray = (int) (0.3 * r + 0.59 * g + 0.11 * b);
        return gray
    else:
        return img

""" 
cnn在图像大小是2的倍数时性能最高, 如果你用的图像大小不是2的倍数，可以在图像边缘补无用像素。 
np.pad(image,((2,3),(2,2)), 'constant', constant_values=(255,))  # 在图像上补2行，下补3行，左补2行，右补2行 
"""

char_set = number   # 如果验证码长度小于4, '_'用来补齐
CHAR_SET_LEN = len(char_set)

# 文本转向量
def text2vec(text):
    text_len = len(text)
    if text_len > MAX_CAPTCHA:
        raise ValueError('验证码最长4个字符')

vector = np.zeros(MAX_CAPTCHA * CHAR_SET_LEN)

def char2pos(c):
        try:
            k = ord(c)-ord('0')
        except:
            raise ValueError('No Map')
        return k

for i, c in enumerate(text):
        idx = i * CHAR_SET_LEN + char2pos(c)
        vector[idx] = 1
    return vector

# 向量转回文本
def vec2text(vec):
    char_pos = vec.nonzero()[0]
    text = []
    for i, c in enumerate(char_pos):
        char_at_pos = i  # c/63
        char_idx = c % CHAR_SET_LEN
        if char_idx < 10:
            char_code = char_idx + ord('0')
        elif char_idx < 36:
            char_code = char_idx - 10 + ord('A')
        elif char_idx < 62:
            char_code = char_idx - 36 + ord('a')
        elif char_idx == 62:
            char_code = ord('_')
        else:
            raise ValueError('error')
        text.append(chr(char_code))
    return "".join(text)

# 生成一个训练batch
def get_next_batch(batch_size=128):
    batch_x = np.zeros([batch_size, IMAGE_HEIGHT * IMAGE_WIDTH])
    batch_y = np.zeros([batch_size, MAX_CAPTCHA * CHAR_SET_LEN])

# 有时生成图像大小不是(60, 160, 3)  
    def wrap_gen_captcha_text_and_image():
        while True:
            text, image = gen_captcha_text_and_image_new()

if image.shape == image_shape:
                return text, image

for i in range(batch_size):
        text, image = wrap_gen_captcha_text_and_image()
        image = convert2gray(image)

batch_x[i, :] = image.flatten() / 255  # (image.flatten()-128)/128  mean为0
        batch_y[i, :] = text2vec(text)

return batch_x, batch_y

####################################################################

X = tf.placeholder(tf.float32, [None, IMAGE_HEIGHT * IMAGE_WIDTH])
Y = tf.placeholder(tf.float32, [None, MAX_CAPTCHA * CHAR_SET_LEN])
keep_prob = tf.placeholder(tf.float32)  # dropout

# 定义CNN
def crack_captcha_cnn(w_alpha=0.01, b_alpha=0.1):
    x = tf.reshape(X, shape=[-1, IMAGE_HEIGHT, IMAGE_WIDTH, 1])

# w_c1_alpha = np.sqrt(2.0/(IMAGE_HEIGHT*IMAGE_WIDTH)) #
    # w_c2_alpha = np.sqrt(2.0/(3*3*32))
    # w_c3_alpha = np.sqrt(2.0/(3*3*64))
    # w_d1_alpha = np.sqrt(2.0/(8*32*64))
    # out_alpha = np.sqrt(2.0/1024)

# 定义三层的卷积神经网络

# 定义第一层的卷积神经网络
    # 定义第一层权重
    w_c1 = tf.Variable(w_alpha * tf.random_normal([3, 3, 1, 32]))
    # 定义第一层的偏置
    b_c1 = tf.Variable(b_alpha * tf.random_normal([32]))
    # 定义第一层的激励函数
    conv1 = tf.nn.relu(tf.nn.bias_add(tf.nn.conv2d(x, w_c1, strides=[1, 1, 1, 1], padding='SAME'), b_c1))
    # conv1 为输入  ksize 表示使用2*2池化，即将2*2的色块转化成1*1的色块
    conv1 = tf.nn.max_pool(conv1, ksize=[1, 2, 2, 1], strides=[1, 2, 2, 1], padding='SAME')
    # dropout防止过拟合。
    conv1 = tf.nn.dropout(conv1, keep_prob)

# 定义第二层的卷积神经网络
    w_c2 = tf.Variable(w_alpha * tf.random_normal([3, 3, 32, 64]))
    b_c2 = tf.Variable(b_alpha * tf.random_normal([64]))
    conv2 = tf.nn.relu(tf.nn.bias_add(tf.nn.conv2d(conv1, w_c2, strides=[1, 1, 1, 1], padding='SAME'), b_c2))
    conv2 = tf.nn.max_pool(conv2, ksize=[1, 2, 2, 1], strides=[1, 2, 2, 1], padding='SAME')
    conv2 = tf.nn.dropout(conv2, keep_prob)

# 定义第三层的卷积神经网络
    w_c3 = tf.Variable(w_alpha * tf.random_normal([3, 3, 64, 64]))
    b_c3 = tf.Variable(b_alpha * tf.random_normal([64]))
    conv3 = tf.nn.relu(tf.nn.bias_add(tf.nn.conv2d(conv2, w_c3, strides=[1, 1, 1, 1], padding='SAME'), b_c3))
    conv3 = tf.nn.max_pool(conv3, ksize=[1, 2, 2, 1], strides=[1, 2, 2, 1], padding='SAME')
    conv3 = tf.nn.dropout(conv3, keep_prob)

# Fully connected layer
    # 随机生成权重
    w_d = tf.Variable(w_alpha * tf.random_normal([1536, 1024]))
    # 随机生成偏置
    b_d = tf.Variable(b_alpha * tf.random_normal([1024]))
    dense = tf.reshape(conv3, [-1, w_d.get_shape().as_list()[0]])
    dense = tf.nn.relu(tf.add(tf.matmul(dense, w_d), b_d))
    dense = tf.nn.dropout(dense, keep_prob)

w_out = tf.Variable(w_alpha * tf.random_normal([1024, MAX_CAPTCHA * CHAR_SET_LEN]))
    b_out = tf.Variable(b_alpha * tf.random_normal([MAX_CAPTCHA * CHAR_SET_LEN]))
    out = tf.add(tf.matmul(dense, w_out), b_out)
    # out = tf.nn.softmax(out)
    return out

# 训练
def train_crack_captcha_cnn():
    # X = tf.placeholder(tf.float32, [None, IMAGE_HEIGHT * IMAGE_WIDTH])
    # Y = tf.placeholder(tf.float32, [None, MAX_CAPTCHA * CHAR_SET_LEN])
    # keep_prob = tf.placeholder(tf.float32)  # dropout
    output = crack_captcha_cnn()
    # loss  
    # loss = tf.reduce_mean(tf.nn.softmax_cross_entropy_with_logits(output, Y))
    loss = tf.reduce_mean(tf.nn.sigmoid_cross_entropy_with_logits(output, Y))
    # 最后一层用来分类的softmax和sigmoid有什么不同？
    # optimizer 为了加快训练 learning_rate应该开始大，然后慢慢衰  
    optimizer = tf.train.AdamOptimizer(learning_rate=0.001).minimize(loss)

predict = tf.reshape(output, [-1, MAX_CAPTCHA, CHAR_SET_LEN])
    max_idx_p = tf.argmax(predict, 2)
    max_idx_l = tf.argmax(tf.reshape(Y, [-1, MAX_CAPTCHA, CHAR_SET_LEN]), 2)
    correct_pred = tf.equal(max_idx_p, max_idx_l)
    accuracy = tf.reduce_mean(tf.cast(correct_pred, tf.float32))

saver = tf.train.Saver()
    with tf.Session() as sess:
            sess.run(tf.global_variables_initializer())

step = 0
            while True:
                batch_x, batch_y = get_next_batch(64)
                _, loss_ = sess.run([optimizer, loss], feed_dict={X: batch_x, Y: batch_y, keep_prob: 0.75})
                print(step, loss_)

# 每100 step计算一次准确率
                if step % 100 == 0:
                    batch_x_test, batch_y_test = get_next_batch(100)
                    acc = sess.run(accuracy, feed_dict={X: batch_x_test, Y: batch_y_test, keep_prob: 1.})
                    print(step, acc)
                    # 如果准确率大于50%,保存模型,完成训练
                    if acc > 0.99:
                        saver.save(sess, "./crack_capcha.model", global_step=step)
                        break
                step += 1

## 训练(如果要训练则去掉下面一行的注释)
train_crack_captcha_cnn()

def crack_captcha():
    output = crack_captcha_cnn()

saver = tf.train.Saver()
    with tf.Session() as sess:
        saver.restore(sess, tf.train.latest_checkpoint('.'))

predict = tf.argmax(tf.reshape(output, [-1, MAX_CAPTCHA, CHAR_SET_LEN]), 2)
        count = 0
        # 因为测试集共40个...写的很草率
        for i in range(40):
            text, image = get_test_captcha_text_and_image(i)
            image = convert2gray(image)
            captcha_image = image.flatten() / 255
            text_list = sess.run(predict, feed_dict={X: [captcha_image], keep_prob: 1})
            predict_text = text_list[0].tolist()
            predict_text = str(predict_text)
            predict_text = predict_text.replace("[", "").replace("]", "").replace(",", "").replace(" ","")
            if text == predict_text:
                count += 1
                check_result = "，预测结果正确"
            else:
                check_result = "，预测结果不正确"
                print("正确: {}  预测: {}".format(text, predict_text) + check_result)

print("正确率:" + str(count) + "/40")
# 测试(如果要测试则去掉下面一行的注释)
# crack_captcha()
```

#### gen_check_code.py(得到训练集输入,需要注意修改root_dir为训练集的输入文件夹,下同)

```
from captcha.image import ImageCaptcha  # pip install captcha
import numpy as np
from PIL import Image
import random
# import matplotlib.pyplot as plt
import os
from random import choice

# 验证码中的字符, 就不用汉字了
number = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9']
# alphabet = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u',
#             'v', 'w', 'x', 'y', 'z']
# ALPHABET = ['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U',
#             'V', 'W', 'X', 'Y', 'Z']

root_dir = "d:\\train"

# 验证码一般都无视大小写；验证码长度4个字符
def random_captcha_text(char_set=number, captcha_size=4):
    captcha_text = []
    for i in range(captcha_size):
        c = random.choice(char_set)
        captcha_text.append(c)
    return captcha_text

# 生成字符对应的验证码
def gen_captcha_text_and_image():
    image = ImageCaptcha()

captcha_text = random_captcha_text()
    captcha_text = ''.join(captcha_text)

captcha = image.generate(captcha_text)
    # image.write(captcha_text, captcha_text + '.jpg')  # 写到文件

captcha_image = Image.open(captcha)
    captcha_image = np.array(captcha_image)
    return captcha_text, captcha_image

def gen_list():
    img_list = []
    for parent, dirnames, filenames in os.walk(root_dir):  # 三个参数：分别返回1.父目录 2.所有文件夹名字（不含路径） 3.所有文件名字
        for filename in filenames:  # 输出文件信息
            img_list.append(filename.replace(".gif",""))
            # print("parent is:" + parent)
            # print("filename is:" + filename)
            # print("the full name of the file is:" + os.path.join(parent, filename))  # 输出文件路径信息
    return img_list
img_list = gen_list()
def gen_captcha_text_and_image_new():
    img = choice(img_list)
    captcha_image = Image.open(root_dir + "\\" + img + ".gif")
    captcha_image = np.array(captcha_image)
    return img, captcha_image

# if __name__ == '__main__':
#     # 测试
#     # text, image = gen_captcha_text_and_image()
#     #
#     # f = plt.figure()
#     # ax = f.add_subplot(111)
#     # ax.text(0.1, 0.9, text, ha='center', va='center', transform=ax.transAxes)
#     # plt.imshow(image)
#     # plt.show()
#     #
#
#     text, image = gen_captcha_text_and_image_new()
#
#     f = plt.figure()
#     ax = f.add_subplot(111)
#     ax.text(0.1, 0.9, text, ha='center', va='center', transform=ax.transAxes)
#     plt.imshow(image)
#     plt.show()
```

#### test_check_code.py(得到测试集输入)

```
from captcha.image import ImageCaptcha  # pip install captcha
import numpy as np
from PIL import Image
import random
import matplotlib.pyplot as plt
import os
from random import choice

root_dir = "d:\\test"

img_list = []
def gen_list():

for parent, dirnames, filenames in os.walk(root_dir):  # 三个参数：分别返回1.父目录 2.所有文件夹名字（不含路径） 3.所有文件名字
        for filename in filenames:  # 输出文件信息
            img_list.append(filename.replace(".gif",""))
            # print("parent is:" + parent)
            # print("filename is:" + filename)
            # print("the full name of the file is:" + os.path.join(parent, filename))  # 输出文件路径信息
    return img_list

img_list = gen_list()
def get_test_captcha_text_and_image(i=None):
    img = img_list[i]
    captcha_image = Image.open(root_dir + "\\" + img + ".gif")
    captcha_image = np.array(captcha_image)
    return img, captcha_image
```

# 4.效果

在测试集上的识别率 
![识别率](http://img.blog.csdn.net/20170520092651729?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvaHVwbGlvbg==/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast "识别率")

# 5.相关文件下载

训练集以及测试集 [百度云下载](https://pan.baidu.com/s/1pLoadZX)

---
转自:[Tensorflow应用之简单验证码识别](http://blog.csdn.net/huplion/article/details/72490467)

附件:

img.zip
tensorflow_img.zip