I try to use a Tensorflow model (created with Keras) in OpenCV/dnn (3.3.0). But I get the following error message:
OpenCV Error: Unspecified error (Unknown layer type Shape in op flatten_1/Shape)
This is the python code to create and export the model.
import os
import sys
import shutil
import subprocess
import numpy as np
import tensorflow as tf
from keras.models import Model
from keras import backend as K
from keras.layers import Dense, Input, Conv2D, Flatten, MaxPooling2D, BatchNormalization
sess = tf.Session()
K.set_session(sess)
# create model
inputs = Input(shape=(64, 64, 3), name='input_layer')
x = Conv2D(8, (3, 3), padding='same', activation='relu')(inputs)
x = MaxPooling2D((2,2))(x)
x = Conv2D(16, (3, 3), padding='same', activation='relu')(x)
x = MaxPooling2D((2,2))(x)
x = Flatten()(x)
x = Dense(64, activation='sigmoid')(x)
x = BatchNormalization()(x)
x = Dense(32, activation='sigmoid')(x)
predictions = Dense(10, activation='softmax', name='output_layer')(x)
model = Model(inputs=inputs, outputs=predictions)
model.compile(optimizer='rmsprop',
loss='categorical_crossentropy',
metrics=['accuracy'])
# train model
data = np.random.random((100, 64, 64, 3))
labels = np.random.randint(2, size=(100, 10))
model.fit(data, labels, epochs=10, batch_size=32)
# create temp directory for export
temp_export_dir = './temp_export/'
if os.path.exists(temp_export_dir):
shutil.rmtree(temp_export_dir)
os.makedirs(temp_export_dir)
# export model to temp directory
with sess.graph.as_default():
saver = tf.train.Saver()
saver.save(sess, temp_export_dir + 'model.ckpt')
tf.train.write_graph(sess.graph.as_graph_def(), temp_export_dir, "graph.pbtxt")
# freeze graph and optimize for inference
_ = subprocess.call("python freeze_graph.py --input_graph=" + temp_export_dir + "graph.pbtxt --input_checkpoint=" + temp_export_dir + "model.ckpt --output_graph=" + temp_export_dir + "frozen_graph.pb --output_node_names=output_layer/Softmax")
_ = subprocess.call("python optimize_for_inference.py --input=" + temp_export_dir + "frozen_graph.pb --output=model.pb --frozen_graph=True --input_names=input_layer --output_names=output_layer/Softmax")
# remove temp directory
#shutil.rmtree(temp_export_dir)
The two external scripts `freeze_graph.py` and `optimize_for_inference.py` come from [tensorflow/python/tools](https://github.com/tensorflow/tensorflow/tree/master/tensorflow/python/tools)
And this is the C++ code to load the model:
#include
int main()
{
cv::dnn::Net net = cv::dnn::readNetFromTensorflow( "model.pb" );
}
I uploaded the file `model.pb` here: http://daiw.de/share/opencv_question_2017-08-23/model.pb
Am I doing something wrong or can OpenCV/dnn simply not import such a model?
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