我在 Keras 中使用一些 tensorflow 函数(reduce_sum 和 l2_normalize)在最后一层构建模型时遇到了这个问题。我已经搜索了一个解决方案,但所有这些都与“Keras 张量”有关。
这是我的代码:
import tensorflow as tf;
from tensorflow.python.keras import backend as K
vgg16_model = VGG16(weights = 'imagenet', include_top = False, input_shape = input_shape);
fire8 = extract_layer_from_model(vgg16_model, layer_name = 'block4_pool');
pool8 = MaxPooling2D((3,3), strides = (2,2), name = 'pool8')(fire8.output);
fc1 = Conv2D(64, (6,6), strides= (1, 1), padding = 'same', name = 'fc1')(pool8);
fc1 = Dropout(rate = 0.5)(fc1);
fc2 = Conv2D(3, (1, 1), strides = (1, 1), padding = 'same', name = 'fc2')(fc1);
fc2 = Activation('relu')(fc2);
fc2 = Conv2D(3, (15, 15), padding = 'valid', name = 'fc_pooling')(fc2);
fc2_norm = K.l2_normalize(fc2, axis = 3);
est = tf.reduce_sum(fc2_norm, axis = (1, 2));
est = K.l2_normalize(est);
FC_model = Model(inputs = vgg16_model.input, outputs = est);
然后是错误:
ValueError: Output tensors to a Model must be the output of a TensorFlow
Layer
(thus holding past layer metadata). Found: Tensor("l2_normalize_3:0", shape=(?, 3), dtype=float32)
我注意到在没有将 fc2 层传递给这些函数的情况下,模型可以正常工作:
FC_model = Model(inputs = vgg16_model.input, outputs = fc2);
有人可以向我解释一下这个问题以及如何解决它的一些建议吗?
最佳答案
我找到了解决问题的方法。 对于遇到相同问题的任何人,您可以使用 Lambda 层来包装您的 tensorflow 操作,这就是我所做的:
from tensorflow.python.keras.layers import Lambda;
def norm(fc2):
fc2_norm = K.l2_normalize(fc2, axis = 3);
illum_est = tf.reduce_sum(fc2_norm, axis = (1, 2));
illum_est = K.l2_normalize(illum_est);
return illum_est;
illum_est = Lambda(norm)(fc2);
关于python - 值错误 : Output tensors to a Model must be the output of a TensorFlow `Layer` ,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/50715928/