from claptcha import Claptcha
import pandas as pd
import os
import numpy as np
import cv2
import keras
from keras.models import Sequential,Model
from keras.layers import Dropout,Activation, \
Convolution2D, GlobalAveragePooling2D, merge,MaxPooling2D,Conv2D,Flatten,Dense,Input
from keras import backend as K
from keras.optimizers import Adam
import fire
from elapsedtimer import ElapsedTimer
from keras.utils import plot_model
def create_dict_char_to_index():
chars = 'abcdefghijklmnopqrstuvwxyz0123456789'.upper()
chars = list(chars)
index = np.arange(len(chars))
char_to_index_dict,index_to_char_dict = {},{}
for v,k in zip(index,chars):
char_to_index_dict[k] = v
index_to_char_dict[v] = k
return char_to_index_dict,index_to_char_dict
def load_img(path,dim=(100,40)):
img = cv2.imread(path,cv2.IMREAD_GRAYSCALE)
img = cv2.resize(img,dim)
img = img.reshape((dim[1],dim[0],1))
#print(img.shape)
return img/255.
class DataGenerator(keras.utils.Sequence):
'Generates data for Keras'
def __init__(self,dest,char_to_index_dict,batch_size=32,n_classes=36,dim=(40,100,1),shuffle=True):
'Initialization'
self.dest = dest
self.files = os.listdir(self.dest)
self.char_to_index_dict = char_to_index_dict
self.batch_size = batch_size
self.n_classes = n_classes
self.dim = dim
self.shuffle = shuffle
self.on_epoch_end()
def __len__(self):
'Denotes the number of batches per epoch'
return int(np.floor(len(self.files) / self.batch_size))
def __getitem__(self, index):
'Generate one batch of data'
# Generate indexes of the batch
indexes = self.indexes[index*self.batch_size:(index+1)*self.batch_size]
# Find list of files to be processed in the batch
list_files = [self.files[k] for k in indexes]
# Generate data
X, y = self.__data_generation(list_files)
return X, y
def on_epoch_end(self):
'Updates indexes after each epoch'
self.indexes = np.arange(len(self.files))
if self.shuffle == True:
np.random.shuffle(self.indexes)
def __data_generation(self,list_files):
'Generates data containing batch_size samples' # X : (n_samples, *dim, n_channels)
# Initialization
dim_h = self.dim[0]
dim_w = self.dim[1]//4
channels = self.dim[2]
X = np.empty((4*len(list_files),dim_h,dim_w,channels))
y = np.empty((4*len(list_files)),dtype=int)
# print(X.shape,y.shape)
# Generate data
k = -1
for f in list_files:
target = list(f.split('.')[0])
target = [self.char_to_index_dict[c] for c in target]
img = load_img(self.dest + f)
img_h,img_w = img.shape[0],img.shape[1]
crop_w = img.shape[1]//4
for i in range(4):
img_crop = img[:,i*crop_w:(i+1)*crop_w]
k+=1
X[k,] = img_crop
y[k] = int(target[i])
return X,y
def _model_(n_classes):
# Build the neural network
input_ = Input(shape=(40,25,1))
# First convolutional layer with max pooling
x = Conv2D(20, (5, 5), padding="same",activation="relu")(input_)
x = MaxPooling2D(pool_size=(2, 2), strides=(2, 2))(x)
x = Dropout(0.2)(x)
# Second convolutional layer with max pooling
x = Conv2D(50, (5, 5), padding="same", activation="relu")(x)
x = MaxPooling2D(pool_size=(2, 2), strides=(2, 2))(x)
x = Dropout(0.2)(x)
# Hidden layer with 1024 nodes
x = Flatten()(x)
x = Dense(1024, activation="relu")(x)
# Output layer with 36 nodes (one for each possible alphabet/digit we predict)
out = Dense(n_classes,activation='softmax')(x)
model = Model(inputs=[input_],outputs=out)
model.compile(loss="sparse_categorical_crossentropy", optimizer="adam", metrics=["accuracy"])
plot_model(model,show_shapes=True, to_file='model.png')
return model
def train(dest_train,dest_val,outdir,batch_size,n_classes,dim,shuffle,epochs,lr):
char_to_index_dict,index_to_char_dict = create_dict_char_to_index()
model = _model_(n_classes)
from keras.utils import plot_model
plot_model(model, to_file=outdir + 'model.png')
train_generator = DataGenerator(dest_train,char_to_index_dict,batch_size,n_classes,dim,shuffle)
val_generator = DataGenerator(dest_val,char_to_index_dict,batch_size,n_classes,dim,shuffle)
model.fit_generator(train_generator,epochs=epochs,validation_data=val_generator)
model.save(outdir + 'captcha_breaker.h5')
def evaluate(model_path,eval_dest,outdir,fetch_target=True):
char_to_index_dict,index_to_char_dict = create_dict_char_to_index()
files = os.listdir(eval_dest)
model = keras.models.load_model(model_path)
predictions,targets = [],[]
for f in files:
if fetch_target == True:
target = list(f.split('.')[0])
targets.append(target)
pred = []
img = load_img(eval_dest + f)
img_h,img_w = img.shape[0],img.shape[1]
crop_w = img.shape[1]//4
for i in range(4):
img_crop = img[:,i*crop_w:(i+1)*crop_w]
img_crop = img_crop[np.newaxis,:]
pred_index = np.argmax(model.predict(img_crop),axis=1)
#print(pred_index)
pred_char = index_to_char_dict[pred_index[0]]
pred.append(pred_char)
predictions.append(pred)
df = pd.DataFrame()
df['files'] = files
df['predictions'] = predictions
if fetch_target == True:
match = []
df['targets'] = targets
accuracy_count = 0
for i in range(len(files)):
if targets[i] == predictions[i]:
accuracy_count+= 1
match.append(1)
else:
match.append(0)
print(f'Accuracy: {accuracy_count/float(len(files))} ')
eval_file = outdir + 'evaluation.csv'
df['match'] = match
df.to_csv(eval_file,index=False)
print(f'Evaluation file written at: {eval_file} ')
if __name__ == '__main__':
with ElapsedTimer('captcha_solver'):
fire.Fire()
