我正在尝试实施研究论文的想法https://arxiv.org/pdf/1507.05717.pdf 使用CNN，双向LSTM和CTC损失以预测图像中的文本。我在Github上找到了一些资源，其中包括tensorflow中的代码，但是由于我是Tensorflow的新手，所以我很难理解它们的代码。有人可以为我提供一个非常简单的简单代码，说明如何使用一组图像及其相应的标签（例如资产，财务等）实施该想法。标签的长度不同，但是图像尺寸固定为width = 200，高度= 20，深度= 1。
这是文本生成代码：
data=[]
labels=[]
length=[]
def GenerateCharacters():
k = 1
for filename in fonts:
font_resource_file = filename
for word in words:
if len(word)>12:
continue
l=function(word)
if l==-1:
continue
for font_size in font_sizes:
font = ImageFont.truetype(font_resource_file, font_size)
TEXT=word
txt = TEXT
(width, height) = font.getsize(txt)
#New Image
FOREGROUND = (255)
background = Image.new('L', (width, height), color = 0)
draw = ImageDraw.Draw(background)
draw.text((0,0), txt, font = font, fill=FOREGROUND)
w,h = background.size
W = int(round(w/float(h)*22))
req_im = np.asarray(background.resize((W, 22)))
if(W<200):
req_im = np.hstack([req_im, np.zeros((22,200-W),dtype='uint8')])
else:
req_im=Image.fromarray(req_im)
req_im=req_im.resize((200,22))
req_im=np.asarray(req_im)
word_image=req_im
# outpath=out_dir+word
# if not os.path.exists(outpath):
# os.makedirs(outpath)
# file_name = os.path.join(outpath,str(k)+'.jpg')
# cv2.imwrite(file_name,word_image)
data.append(word_image)
l=np.array(l)
pad=np.full((1,12-l.shape[0]),-1)
l=np.append(l,pad)
labels.append(l)
length.append(len(word))
k = k + 1
return
模型和图形代码：
def run_ctc():
graph = tf.Graph()
with graph.as_default():
input_data=tf.placeholder(tf.float32,[None, height, width, depth])
labelss=tf.sparse_placeholder(tf.int32)
sequence_length=tf.placeholder(tf.int32, [None])
conv1=tf.layers.conv2d(inputs=input_data,
filters=64,
kernel_size=[3, 3],
strides=[1,1],
padding="same",
activation=tf.nn.relu)
print "Conv1",conv1.shape
bn1=tf.layers.batch_normalization(inputs=conv1,axis=-1)
print "BN1",bn1.shape
pool1=tf.layers.max_pooling2d(inputs=bn1,pool_size=[2,2],strides=[2,2])
print "Pool1",pool1.shape
conv2=tf.layers.conv2d(inputs=pool1,
filters=128,
kernel_size=[3, 3],
strides=[1,1],
padding="same",
activation=tf.nn.relu)
print "Conv2",conv2.shape
bn2=tf.layers.batch_normalization(inputs=conv2,axis=-1)
print "BN2",bn2.shape
pool2=tf.layers.max_pooling2d(inputs=bn2,pool_size=[2,2],strides=[2,2])
print "Pool2",pool2.shape
conv3=tf.layers.conv2d(inputs=pool2,
filters=256,
kernel_size=[3, 3],
strides=[1,1],
padding="same",
activation=tf.nn.relu)
print "Conv3",conv3.shape
bn3=tf.layers.batch_normalization(inputs=conv3,axis=-1)
print "BN3",bn3.shape
pool3=tf.layers.max_pooling2d(inputs=bn3,pool_size=[2,2],strides=[2,2])
print "Pool3",pool3.shape
conv4=tf.layers.conv2d(inputs=pool3,
filters=512,
kernel_size=[3, 3],
strides=[1,1],
padding="same",
activation=tf.nn.relu)
print "Conv4",conv4.shape
bn4=tf.layers.batch_normalization(inputs=conv4,axis=-1)
print "BN4",bn4.shape
pool4=tf.layers.max_pooling2d(inputs=bn4,pool_size=[2,2],strides=[2,2])
print "Pool4",pool4.shape
features = tf.squeeze(pool4, axis=1, name='features')
print "CNN features",features.shape
rnn_ = tf.transpose(features, perm=[1, 0, 2], name='time_major')
print "RNN_seq",rnn_.shape
weight_initializer = tf.truncated_normal_initializer(stddev=0.01)
with tf.variable_scope('forward'):
cell_fw = tf.contrib.rnn.LSTMCell(512,initializer=weight_initializer)
with tf.variable_scope('backward'):
cell_bw = tf.contrib.rnn.LSTMCell(512,initializer=weight_initializer)
with tf.variable_scope('Bdrnn',reuse=tf.AUTO_REUSE):
rnn_output,_ = tf.nn.bidirectional_dynamic_rnn(cell_fw, cell_bw, rnn_,
sequence_length=sequence_length,
time_major=True,
dtype=tf.float32)
rnn_output_stack = tf.concat(rnn_output,2,name='output_stack')
logit_activation = tf.nn.relu
weight_initializer = tf.contrib.layers.variance_scaling_initializer()
bias_initializer = tf.constant_initializer(value=0.0)
logit_output = tf.layers.dense( rnn_output_stack, classes+1,
activation=logit_activation,
kernel_initializer=weight_initializer,
bias_initializer=bias_initializer)
loss = tf.nn.ctc_loss(labelss,logit_output,sequence_length,time_major=True )
total_loss = tf.reduce_mean(loss)
optimizer = tf.train.MomentumOptimizer(learning_rate=0.005, momentum=0.9).minimize(total_loss)
decoded, log_prob = tf.nn.ctc_greedy_decoder(logit_output, sequence_length)
ler = tf.reduce_mean(tf.edit_distance(tf.cast(decoded[0], tf.int32),labelss))
with tf.Session(graph=graph) as sess:
init=tf.global_variables_initializer()
init_l=tf.local_variables_initializer()
sess.run(init)
sess.run(init_l)
for i in range(epochs):
train_cost = train_ler = 0
print("Epoch: {}").format(i)
for batch_no in range(total_train_batches):
feed = {input_data: batch_data(train_data,batch_no,total_train_batches,batch_size),
labelss:sess.run(sparse_tuples(batch_data(train_labels,batch_no,total_train_batches,batch_size))),
sequence_length: batch_data(train_seq_len,batch_no,total_train_batches,batch_size)}
da,l,seq=sess.run([input_data,labelss,sequence_length],feed_dict=feed)
# print da.shape
# print seq.shape
# prediction=tf.argmax(tf.nn.softmax(logit_output),axis=2)
original=convert(train_labels[batch_no])
print "Original Label",original
batch_cost,_ = sess.run([total_loss,optimizer],feed_dict=feed)
train_cost += batch_cost*batch_size
train_ler += sess.run(ler, feed_dict=feed)*batch_size
print "Batch_loss",batch_cost
d = sess.run(decoded[0], feed_dict=feed)
str_decoded = convert(d[1])
print "Decoded Label",str_decoded
train_cost /= num_train_examples
train_ler /= num_train_examples
for batch_no in range(total_val_batches):
val_feed = {input_data: batch_data(val_data,batch_no,total_val_batches,batch_size),
labelss: sess.run(sparse_tuples(batch_data(val_labels,batch_no,total_val_batches,batch_size))),
sequence_length: batch_data(val_seq_length,batch_no,total_val_batches,batch_size)}
val_cost,val_ler = sess.run([total_loss, ler], feed_dict=val_feed)
log = "Epoch {}/{}, train_cost = {:.3f}, train_ler = {:.3f}, val_cost = {:.3f}, val_ler = {:.3f}"
print(log.format(i+1, epochs, train_cost, train_ler,val_cost, val_ler))
if __name__ == '__main__':
run_ctc()
我面临的问题是我丢失了一批inf，与原始标签相比，解码后的标签不正确。
