Keras预期序列_2具有形状(None,2),但得到的数组具有形状(32,1)

2024-03-29 07:33:34 发布

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我用预先训练过的VGG16用keras建立了一个模型

 model = Sequential()
model.add(ZeroPadding2D((1, 1), input_shape=(3, img_width, img_height)))

model.add(Convolution2D(64, 3, 3, activation='relu', name='conv1_1'))
model.add(ZeroPadding2D((1, 1)))
model.add(Convolution2D(64, 3, 3, activation='relu', name='conv1_2'))
model.add(MaxPooling2D((2, 2), strides=(2, 2)))

model.add(ZeroPadding2D((1, 1)))
model.add(Convolution2D(128, 3, 3, activation='relu', name='conv2_1'))
model.add(ZeroPadding2D((1, 1)))
model.add(Convolution2D(128, 3, 3, activation='relu', name='conv2_2'))
model.add(MaxPooling2D((2, 2), strides=(2, 2)))

model.add(ZeroPadding2D((1, 1)))
model.add(Convolution2D(256, 3, 3, activation='relu', name='conv3_1'))
model.add(ZeroPadding2D((1, 1)))
model.add(Convolution2D(256, 3, 3, activation='relu', name='conv3_2'))
model.add(ZeroPadding2D((1, 1)))
model.add(Convolution2D(256, 3, 3, activation='relu', name='conv3_3'))
model.add(MaxPooling2D((2, 2), strides=(2, 2)))

model.add(ZeroPadding2D((1, 1)))
model.add(Convolution2D(512, 3, 3, activation='relu', name='conv4_1'))
model.add(ZeroPadding2D((1, 1)))
model.add(Convolution2D(512, 3, 3, activation='relu', name='conv4_2'))
model.add(ZeroPadding2D((1, 1)))
model.add(Convolution2D(512, 3, 3, activation='relu', name='conv4_3'))
model.add(MaxPooling2D((2, 2), strides=(2, 2)))

model.add(ZeroPadding2D((1, 1)))
model.add(Convolution2D(512, 3, 3, activation='relu', name='conv5_1'))
model.add(ZeroPadding2D((1, 1)))
model.add(Convolution2D(512, 3, 3, activation='relu', name='conv5_2'))
model.add(ZeroPadding2D((1, 1)))
model.add(Convolution2D(512, 3, 3, activation='relu', name='conv5_3'))
model.add(MaxPooling2D((2, 2), strides=(2, 2)))

# load the weights of the VGG16 networks
# (trained on ImageNet, won the ILSVRC competition in 2014)
# note: when there is a complete match between your model definition
# and your weight savefile, you can simply call model.load_weights(filename)
assert os.path.exists(vgg_model), 'Model weights not found (see "weights_path" variable in script).'
f = h5py.File(vgg_model)
for k in range(f.attrs['nb_layers']):
    if k >= len(model.layers):
        # we don't look at the last (fully-connected) layers in the savefile
        break
    g = f['layer_{}'.format(k)]
    weights = [g['param_{}'.format(p)] for p in range(g.attrs['nb_params'])]
    model.layers[k].set_weights(weights)
f.close()
print('Model loaded.')

# build a classifier model to put on top of the convolutional model
top_model = Sequential()
top_model.add(Flatten(input_shape=model.output_shape[1:]))
top_model.add(Dense(256, activation='relu'))
top_model.add(Dropout(0.5))
top_model.add(Dense(2, activation='softmax'))

但是,当使用fit函数运行模型时,它抛出了一个异常

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这里的问题是什么(注意:我使用fit from directory函数来训练我的模型)。在


Tags: thenamein模型addmodellayerstop
2条回答

问题是你的训练标签。 很难给出一个确切的答案,因为你在这里没有向我们展示你拥有的标签类型和你所做的编译。在

我可以继续猜测你是在用二进制或分类的交叉熵进行编译。在

如果我猜对了,让我们称你的标签为“Y”,用以下代码为他们准备培训:

from keras.utils import np_utils
Y = np_utils.to_categorical(Y)

提示:当你进行二元分类(两个类)时,你可以让最后一个密集层输出1而不是2。在标签中,为一个类选择0,为另一个类选择1。这样你就可以避免你现在正在处理的问题。在

你的问题在于flow_from_directory。您应该更改class_mode = "categorical"。此外,您的二进制分类设置并不常见。您应该将最后一层更改为:

top_model.add(Dense(1, activation='sigmoid'))

然后将loss="binary_crossentropy"class_mode="binary"留在生成器中,或者(在第二种情况下)离开:

^{pr2}$

并在生成器中设置loss="categorical_crossentropy"class_mode="categorical"。在

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