Keras 使用 Lambda层详解

我就废话不多说了，大家还是直接看代码吧！

from tensorflow.python.keras.models import Sequential, Model
from tensorflow.python.keras.layers import Dense, Flatten, Conv2D, MaxPool2D, Dropout, Conv2DTranspose, Lambda, Input, Reshape, Add, Multiply
from tensorflow.python.keras.optimizers import Adam

def deconv(x):
 height = x.get_shape()[1].value
 width = x.get_shape()[2].value

new_height = height*2
 new_width = width*2

x_resized = tf.image.resize_images(x, [new_height, new_width], tf.image.ResizeMethod.NEAREST_NEIGHBOR)

return x_resized

def Generator(scope='generator'):
 imgs_noise = Input(shape=inputs_shape)
 x = Conv2D(filters=32, kernel_size=(9,9), strides=(1,1), padding='same', activation='relu')(imgs_noise)
 x = Conv2D(filters=64, kernel_size=(3,3), strides=(2,2), padding='same', activation='relu')(x)
 x = Conv2D(filters=128, kernel_size=(3,3), strides=(2,2), padding='same', activation='relu')(x)

x1 = Conv2D(filters=128, kernel_size=(3,3), strides=(1,1), padding='same', activation='relu')(x)
 x1 = Conv2D(filters=128, kernel_size=(3,3), strides=(1,1), padding='same', activation='relu')(x1)
 x2 = Add()([x1, x])

x3 = Conv2D(filters=128, kernel_size=(3,3), strides=(1,1), padding='same', activation='relu')(x2)
 x3 = Conv2D(filters=128, kernel_size=(3,3), strides=(1,1), padding='same', activation='relu')(x3)
 x4 = Add()([x3, x2])

x5 = Conv2D(filters=128, kernel_size=(3,3), strides=(1,1), padding='same', activation='relu')(x4)
 x5 = Conv2D(filters=128, kernel_size=(3,3), strides=(1,1), padding='same', activation='relu')(x5)
 x6 = Add()([x5, x4])

x = MaxPool2D(pool_size=(2,2))(x6)

x = Lambda(deconv)(x)
 x = Conv2D(filters=64, kernel_size=(3, 3), strides=(1,1), padding='same',activation='relu')(x)
 x = Lambda(deconv)(x)
 x = Conv2D(filters=32, kernel_size=(3, 3), strides=(1,1), padding='same',activation='relu')(x)
 x = Lambda(deconv)(x)
 x = Conv2D(filters=3, kernel_size=(3, 3), strides=(1, 1), padding='same',activation='tanh')(x)

x = Lambda(lambda x: x+1)(x)
 y = Lambda(lambda x: x*127.5)(x)

model = Model(inputs=imgs_noise, outputs=y)
 model.summary()

return model

my_generator = Generator()
my_generator.compile(loss='binary_crossentropy', optimizer=Adam(0.7, decay=1e-3), metrics=['accuracy'])

补充知识：含有Lambda自定义层keras模型，保存遇到的问题及解决方案

一，许多应用，keras含有的层已经不能满足要求，需要透过Lambda自定义层来实现一些layer，这个情况下，只能保存模型的权重，无法使用model.save来保存模型。保存时会报

TypeError: can't pickle _thread.RLock objects

二，解决方案，为了便于后续的部署，可以转成tensorflow的PB进行部署。

from keras.models import load_model
import tensorflow as tf
import os, sys
from keras import backend as K
from tensorflow.python.framework import graph_util, graph_io

def h5_to_pb(h5_weight_path, output_dir, out_prefix="output_", log_tensorboard=True):
 if not os.path.exists(output_dir):
   os.mkdir(output_dir)
 h5_model = build_model()
 h5_model.load_weights(h5_weight_path)
 out_nodes = []
 for i in range(len(h5_model.outputs)):
   out_nodes.append(out_prefix + str(i + 1))
   tf.identity(h5_model.output[i], out_prefix + str(i + 1))
 model_name = os.path.splitext(os.path.split(h5_weight_path)[-1])[0] + '.pb'
 sess = K.get_session()
 init_graph = sess.graph.as_graph_def()
 main_graph = graph_util.convert_variables_to_constants(sess, init_graph, out_nodes)
 graph_io.write_graph(main_graph, output_dir, name=model_name, as_text=False)
 if log_tensorboard:
   from tensorflow.python.tools import import_pb_to_tensorboard
   import_pb_to_tensorboard.import_to_tensorboard(os.path.join(output_dir, model_name), output_dir)

def build_model():
 inputs = Input(shape=(784,), name='input_img')
 x = Dense(64, activation='relu')(inputs)
 x = Dense(64, activation='relu')(x)
 y = Dense(10, activation='softmax')(x)
 h5_model = Model(inputs=inputs, outputs=y)
 return h5_model

if __name__ == '__main__':
 if len(sys.argv) == 3:
   # usage: python3 h5_to_pb.py h5_weight_path output_dir
   h5_to_pb(h5_weight_path=sys.argv[1], output_dir=sys.argv[2])

来源：https://blog.csdn.net/a4775019136/article/details/99336591