有些模型存在多个输出在计算loss的情况,其中比较典型的如hed边缘检测网络,该网络具体介绍可以看之前的博客;hed网络有多个输出,写法如下;
实例一
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66def hed(): # Input img_input = Input(shape=(480,480,3), name='input') # Block 1 x = Conv2D(64, (3, 3), activation='relu', padding='same', name='block1_conv1')(img_input) x = Conv2D(64, (3, 3), activation='relu', padding='same', name='block1_conv2')(x) b1= side_branch(x, 1) # 480 480 1 x = MaxPooling2D((2, 2), strides=(2, 2), padding='same', name='block1_pool')(x) # 240 240 64 # Block 2 x = Conv2D(128, (3, 3), activation='relu', padding='same', name='block2_conv1')(x) x = Conv2D(128, (3, 3), activation='relu', padding='same', name='block2_conv2')(x) b2= side_branch(x, 2) # 480 480 1 x = MaxPooling2D((2, 2), strides=(2, 2), padding='same', name='block2_pool')(x) # 120 120 128 # Block 3 x = Conv2D(256, (3, 3), activation='relu', padding='same', name='block3_conv1')(x) x = Conv2D(256, (3, 3), activation='relu', padding='same', name='block3_conv2')(x) x = Conv2D(256, (3, 3), activation='relu', padding='same', name='block3_conv3')(x) b3= side_branch(x, 4) # 480 480 1 x = MaxPooling2D((2, 2), strides=(2, 2), padding='same', name='block3_pool')(x) # 60 60 256 # Block 4 x = Conv2D(512, (3, 3), activation='relu', padding='same', name='block4_conv1')(x) x = Conv2D(512, (3, 3), activation='relu', padding='same', name='block4_conv2')(x) x = Conv2D(512, (3, 3), activation='relu', padding='same', name='block4_conv3')(x) b4= side_branch(x, 8) # 480 480 1 x = MaxPooling2D((2, 2), strides=(2, 2), padding='same', name='block4_pool')(x) # 30 30 512 # Block 5 x = Conv2D(512, (3, 3), activation='relu', padding='same', name='block5_conv1')(x) x = Conv2D(512, (3, 3), activation='relu', padding='same', name='block5_conv2')(x) x = Conv2D(512, (3, 3), activation='relu', padding='same', name='block5_conv3')(x) # 30 30 512 b5= side_branch(x, 16) # 480 480 1 # fuse fuse = Concatenate(axis=-1)([b1, b2, b3, b4, b5]) fuse = Conv2D(1, (1,1), padding='same', use_bias=False, activation=None)(fuse) # 480 480 1 # outputs o1 = Activation('sigmoid', name='o1')(b1) o2 = Activation('sigmoid', name='o2')(b2) o3 = Activation('sigmoid', name='o3')(b3) o4 = Activation('sigmoid', name='o4')(b4) o5 = Activation('sigmoid', name='o5')(b5) ofuse = Activation('sigmoid', name='ofuse')(fuse) # model model = Model(inputs=[img_input], outputs=[o1, o2, o3, o4, o5, ofuse]) filepath = './models/vgg16_weights_tf_dim_ordering_tf_kernels_notop.h5' # load_weights_from_hdf5_group_by_name(model, filepath) adam = Adam(lr = 1e-4, beta_1=0.9, beta_2=0.999, epsilon=1e-08, decay=0.0001) model.compile(optimizer= adam, loss={'o1': cross_entropy_balanced, 'o2': cross_entropy_balanced, 'o3': cross_entropy_balanced, 'o4': cross_entropy_balanced, 'o5': cross_entropy_balanced, 'ofuse': cross_entropy_balanced, }, metrics={'ofuse': ofuse_pixel_error}) return model
实例二
同时该博客也提供了类似方法https://blog.csdn.net/u012938704/article/details/79904173,搬运一下如下;
部分代码
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38# create the base pre-trained model input_tensor = Input(shape=(299, 299, 3)) base_model = Xception(include_top=True, weights='imagenet', input_tensor=None, input_shape=None) plot_model(base_model, to_file='xception_model.png') base_model.layers.pop() base_model.outputs = [base_model.layers[-1].output] base_model.layers[-1].outbound_nodes = [] base_model.output_layers = [base_model.layers[-1]] feature = base_model img1 = Input(shape=(299, 299, 3), name='img_1') img2 = Input(shape=(299, 299, 3), name='img_2') feature1 = feature(img1) feature2 = feature(img2) # Three loss functions category_predict1 = Dense(100, activation='softmax', name='ctg_out_1')( Dropout(0.5)(feature1) ) category_predict2 = Dense(100, activation='softmax', name='ctg_out_2')( Dropout(0.5)(feature2) ) dis = Lambda(eucl_dist, name='square')([feature1, feature2]) judge = Dense(2, activation='softmax', name='bin_out')(dis) model = Model(inputs=[img1, img2], outputs=[category_predict1, category_predict2, judge]) model.compile(optimizer=SGD(lr=0.0001, momentum=0.9), loss={ 'ctg_out_1': 'categorical_crossentropy', 'ctg_out_2': 'categorical_crossentropy', 'bin_out': 'categorical_crossentropy'}, loss_weights={ 'ctg_out_1': 1., 'ctg_out_2': 1., 'bin_out': 0.5 }, metrics=['accuracy'])
完整代码:https://github.com/ahangchen/keras-dogs/blob/master/single/single_model.py
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180import os import numpy as np os.environ["CUDA_DEVICE_ORDER"] = "PCI_BUS_ID" # see issue #152 os.environ["CUDA_VISIBLE_DEVICES"] = "1" from keras import Input from keras.applications import Xception, InceptionV3 from keras.callbacks import EarlyStopping, ModelCheckpoint, ReduceLROnPlateau from keras.layers import Dense, Dropout, concatenate, maximum from keras.models import Model, load_model from keras.optimizers import SGD from keras.preprocessing.image import ImageDataGenerator from keras.utils import plot_model train_datagen = ImageDataGenerator( rescale=1. / 255, shear_range=0.2, width_shift_range=0.4, height_shift_range=0.4, rotation_range=90, zoom_range=0.7, horizontal_flip=True, vertical_flip=True) test_datagen = ImageDataGenerator(rescale=1. / 255) batch_size = 48 train_generator = train_datagen.flow_from_directory( '/hdd/cwh/dog_keras_train', # '/home/cwh/coding/data/cwh/test1', target_size=(299, 299), # batch_size=1, batch_size=batch_size, class_mode='categorical') validation_generator = test_datagen.flow_from_directory( '/hdd/cwh/dog_keras_valid', # '/home/cwh/coding/data/cwh/test1', target_size=(299, 299), # batch_size=1, batch_size=batch_size, class_mode='categorical') def triple_generator(generator): while True: x, y = generator.next() yield x, [y, y, y, y] early_stopping = EarlyStopping(monitor='val_loss', patience=3) auto_lr = ReduceLROnPlateau(monitor='val_loss', factor=0.1, patience=3, verbose=0, mode='auto', epsilon=0.0001, cooldown=0, min_lr=0) if os.path.exists('dog_single_xception.h5'): model = load_model('dog_single_xception.h5') else: # create the base pre-trained model input_tensor = Input(shape=(299, 299, 3)) base_model1 = Xception(include_top=True, weights='imagenet', input_tensor=None, input_shape=None) base_model1 = Model(inputs=[base_model1.input], outputs=[base_model1.get_layer('avg_pool').output], name='xception') base_model2 = InceptionV3(include_top=True, weights='imagenet', input_tensor=None, input_shape=None) base_model2 = Model(inputs=[base_model2.input], outputs=[base_model2.get_layer('avg_pool').output], name='inceptionv3') img1 = Input(shape=(299, 299, 3), name='img_1') feature1 = base_model1(img1) feature2 = base_model2(img1) # let's add a fully-connected layer category_predict1 = Dense(100, activation='softmax', name='ctg_out_1')( Dropout(0.5)( feature1 ) ) category_predict2 = Dense(100, activation='softmax', name='ctg_out_2')( Dropout(0.5)( feature2 ) ) category_predict = Dense(100, activation='softmax', name='ctg_out')( concatenate([feature1, feature2]) ) max_category_predict = maximum([category_predict1, category_predict2]) model = Model(inputs=[img1], outputs=[category_predict1, category_predict2, category_predict, max_category_predict]) # model.save('dog_xception.h5') plot_model(model, to_file='single_model.png') # first: train only the top layers (which were randomly initialized) # i.e. freeze all convolutional InceptionV3 layers for layer in base_model1.layers: layer.trainable = False for layer in base_model2.layers: layer.trainable = False # compile the model (should be done *after* setting layers to non-trainable) model.compile(optimizer='nadam', loss={ 'ctg_out_1': 'categorical_crossentropy', 'ctg_out_2': 'categorical_crossentropy', 'ctg_out': 'categorical_crossentropy', 'maximum_1': 'categorical_crossentropy' }, metrics=['accuracy']) # model = make_parallel(model, 3) # train the model on the new data for a few epochs model.fit_generator(triple_generator(train_generator), steps_per_epoch=16500 / batch_size + 1, epochs=30, validation_data=triple_generator(validation_generator), validation_steps=1800 / batch_size + 1, callbacks=[early_stopping, auto_lr]) model.save('dog_single_xception.h5') # at this point, the top layers are well trained and we can start fine-tuning # convolutional layers from inception V3. We will freeze the bottom N layers # and train the remaining top layers. # let's visualize layer names and layer indices to see how many layers # we should freeze: for i, layer in enumerate(model.layers): print(i, layer.name) # we chose to train the top 2 inception blocks, i.e. we will freeze # the first 172 layers and unfreeze the rest: cur_base_model = model.layers[1] for layer in cur_base_model.layers[:105]: layer.trainable = False for layer in cur_base_model.layers[105:]: layer.trainable = True cur_base_model = model.layers[2] for layer in cur_base_model.layers[:262]: layer.trainable = False for layer in cur_base_model.layers[262:]: layer.trainable = True # we need to recompile the model for these modifications to take effect # we use SGD with a low learning rate model.compile(optimizer=SGD(lr=0.0001, momentum=0.9), loss={ 'ctg_out_1': 'categorical_crossentropy', 'ctg_out_2': 'categorical_crossentropy', 'ctg_out': 'categorical_crossentropy', 'maximum_1': 'categorical_crossentropy' }, metrics=['accuracy']) batch_size = batch_size * 3 / 4 train_generator = test_datagen.flow_from_directory( '/hdd/cwh/dog_keras_train', # '/home/cwh/coding/data/cwh/test1', target_size=(299, 299), # batch_size=1, batch_size=batch_size, class_mode='categorical') validation_generator = test_datagen.flow_from_directory( '/hdd/cwh/dog_keras_valid', # '/home/cwh/coding/data/cwh/test1', target_size=(299, 299), # batch_size=1, batch_size=batch_size, class_mode='categorical') # we train our model again (this time fine-tuning the top 2 inception blocks # alongside the top Dense layers save_model = ModelCheckpoint('xception-tuned{epoch:02d}-{val_ctg_out_acc:.2f}.h5') model.fit_generator(triple_generator(train_generator), steps_per_epoch=16500 / batch_size + 1, epochs=30, validation_data=triple_generator(validation_generator), validation_steps=1800 / batch_size + 1, callbacks=[early_stopping, auto_lr, save_model]) # otherwise the generator would loop indefinitely model.save('dog_single_xception_tuned.h5')
最后
以上就是欢喜啤酒最近收集整理的关于针对keras模型多输出或多损失方法使用实例一实例二的全部内容,更多相关针对keras模型多输出或多损失方法使用实例一实例二内容请搜索靠谱客的其他文章。
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