Converting a model trained and saved with tf.estimator to .pb - tensorflow

I have a model trained with tf.estimator and it was exported after training as below
serving_input_fn = tf.estimator.export.build_raw_serving_input_receiver_fn(
feature_placeholders)
classifier.export_savedmodel(
r'./path/to/model/trainedModel', serving_input_fn)
This gives me a saved_model.pb and a folder which contains weights as a .data file. I can reload the saved model using
predictor = tf.contrib.predictor.from_saved_model(r'./path/to/model/trainedModel')
I'd like to run this model on android and that requires the model to be in .pb format. How can I freeze this predictor for use on android platform?

I don't deploy to Android, so you might need to customize the steps a bit, but this is how I do this:
Run <tensorflow_root_installation>/python/tools/freeze_graph.py with arguments --input_saved_model_dir=<path_to_the_savedmodel_directory>, --output_node_names=<full_name_of_the_output_node> (you can get the name of the output node from graph.pbtxt, although that's not the most comfortable of ways), --output_graph=frozen_model.pb
(optionally) Run <tensorflow_root_installation>/python/tools/optimize_for_inference.py with adequate arguments. Alternatively you can look up the Graph Transform Tool and selectively apply optimizations.
At the end of step 1 you'll already have a frozen model with no variables left, that you can then deploy to Android.

Related

Use Tensorflow2 saved model for object detection

im quite new to object detection but i managed to train my first Tensorflow custom model yesterday. I think it worked fine besides some warnings, at least i got my exported_model folder with checkpoint, saved model and pipeline.config. I built it with exporter_main_v2.py from Tensorflow. I just loaded some images of deers and want to try to detect some on different pictures.
That's what i would like to test now, but i dont know how. I already did an object detection tutorial with pre trained models and it worked fine. I tried to just replace config_file_path, saved_model_path and image_path with the paths linking to my exported model but it didnt work:
error: OpenCV(4.6.0) D:\a\opencv-python\opencv-python\opencv\modules\dnn\src\tensorflow\tf_io.cpp:42: error: (-2:Unspecified error) FAILED: ReadProtoFromBinaryFile(param_file, param). Failed to parse GraphDef file: D:\VSCode\Machine_Learning_Tests\Tensorflow\workspace\exported_models\first_model\saved_model\saved_model.pb in function 'cv::dnn::ReadTFNetParamsFromBinaryFileOrDie'
There are endless tutorials on how to train custom detection but i cant find a good explanation how to manually test my exported model.
Thanks in advance!
EDIT: I need to know how to build a script where i can import a model i saved with Tensorflow exporter_main_v2.py and an image i want to test this model on and get a result, either in text or with rectangels in picture. Seeing many tutorials but none works for me with a model i saved with Tensorflow exporter_main_v2.py
From the error it looks like you have a model saved as .pb. If you want to do inference you can write something like this:
# load the model
model = tf.keras.models.load_model(my_model_dir)
prediction = model.predict(x=x_test, ...)
You'll have to set x which is the only mandatory argument. It is your test dataset (the images you want to obtain predictions from). Also, predict is useful when you have a great amount of images to predict. It handles the prediction in a batched way, avoiding filling up the memory. If you have just a few you can use directly the __call__() method of your model, like this:
prediction = model(x_test, training=False)
More about prediction can be found at the Tensorflow documentation.

How to generate .tf/.tflite files from python

I am trying to generate the custom tensor flow model (tf/tflite file) which i wanted to use for my mobile application.
I have gone through few machine learning and tensor flow blogs, from there I started to generate a simple ML model.
https://www.datacamp.com/community/tutorials/tensorflow-tutorial
https://www.edureka.co/blog/tensorflow-object-detection-tutorial/
https://blog.metaflow.fr/tensorflow-how-to-freeze-a-model-and-serve-it-with-a-python-api-d4f3596b3adc
https://www.youtube.com/watch?v=ICY4Lvhyobk
All these are really nice and they guided me to do the below steps,
i)Install all necessary tools (TensorFlow,Python,Jupyter,etc).
ii)Load the Training and testing Data.
iii)Run the tensor flow session for train and evaluate the results.
iv)Steps to increase the accuracy
But i am not able to generate the .tf/.tflite files.
I tried the following code, but that generates an empty file.
converter = tf.contrib.lite.TFLiteConverter.from_session(sess,[],[])
model = converter.convert()
file = open( 'model.tflite' , 'wb' )
file.write( model )
I have checked few answers in stackoverflow and according to my understanding in-order to generate the .tf files we need to create the pb files, freezing the pb file and then generating the .tf files.
But how can we achieve this?
Tensorflow provides Tflite converter to convert saved model to Tflite model.For more details find here.
tf.lite.TFLiteConverter.from_saved_model() (recommended): Converts a SavedModel.
tf.lite.TFLiteConverter.from_keras_model(): Converts a Keras model.
tf.lite.TFLiteConverter.from_concrete_functions(): Converts concrete functions.

Using model optimizer for tensorflow slim models

I am aiming to inference tensorflow slim model with Intel OpenVINO optimizer. Using open vino docs and slides for inference and tf slim docs for training model.
It's a multi-class classification problem. I have trained tf slim mobilnet_v2 model from scratch (using sript train_image_classifier.py). Evaluation of trained model on test set gives relatively good results to begin with (using script eval_image_classifier.py):
eval/Accuracy[0.8017]eval/Recall_5[0.9993]
However, single .ckpt file is not saved (even though at the end of train_image_classifier.py run there is a message like "model.ckpt is saved to checkpoint_dir"), there are 3 files (.ckpt-180000.data-00000-of-00001, .ckpt-180000.index, .ckpt-180000.meta) instead.
OpenVINO model optimizer requires a single checkpoint file.
According to docs I call mo_tf.py with following params:
python mo_tf.py --input_model D:/model/mobilenet_v2_224.pb --input_checkpoint D:/model/model.ckpt-180000 -b 1
It gives the error (same if pass --input_checkpoint D:/model/model.ckpt):
[ ERROR ] The value for command line parameter "input_checkpoint" must be existing file/directory, but "D:/model/model.ckpt-180000" does not exist.
Error message is clear, there are not such files on disk. But as I know most tf utilities convert .ckpt-????.meta to .ckpt under the hood.
Trying to call:
python mo_tf.py --input_model D:/model/mobilenet_v2_224.pb --input_meta_graph D:/model/model.ckpt-180000.meta -b 1
Causes:
[ ERROR ] Unknown configuration of input model parameters
It doesn't matter for me in which way I will transfer graph to OpenVINO intermediate representation, just need to reach that result.
Thanks a lot.
EDIT
I managed to run OpenVINO model optimizer on frozen graph of tf slim model. However I still have no idea why had my previous attempts (based on docs) failed.
you can try converting the model to frozen format (.pb) and then convert the model using OpenVINO.
.ckpt-meta has the metagraph. The computation graph structure without variable values.
the one you can observe in tensorboard.
.ckpt-data has the variable values,without the skeleton or structure. to restore a model we need both meta and data files.
.pb file saves the whole graph (meta+data)
As per the documentation of OpenVINO:
When a network is defined in Python* code, you have to create an inference graph file. Usually, graphs are built in a form that allows model training. That means that all trainable parameters are represented as variables in the graph. To use the graph with the Model Optimizer, it should be frozen.
https://software.intel.com/en-us/articles/OpenVINO-Using-TensorFlow
the OpenVINO optimizes the model by converting the weighted graph passed in frozen form.

What is the use of a *.pb file in TensorFlow and how does it work?

I am using some implementation for creating a face recognition which uses this file:
"facenet.load_model("20170512-110547/20170512-110547.pb")"
What is the use of this file? I am not sure how it works.
console log :
Model filename: 20170512-110547/20170512-110547.pb
distance = 0.72212267
Github link of the actual owner of the code
https://github.com/arunmandal53/facematch
pb stands for protobuf. In TensorFlow, the protbuf file contains the graph definition as well as the weights of the model. Thus, a pb file is all you need to be able to run a given trained model.
Given a pb file, you can load it as follow.
def load_pb(path_to_pb):
with tf.gfile.GFile(path_to_pb, "rb") as f:
graph_def = tf.GraphDef()
graph_def.ParseFromString(f.read())
with tf.Graph().as_default() as graph:
tf.import_graph_def(graph_def, name='')
return graph
Once you have loaded the graph, you can basically do anything. For instance, you can retrieve tensors of interest with
input = graph.get_tensor_by_name('input:0')
output = graph.get_tensor_by_name('output:0')
and use regular TensorFlow routine like:
sess.run(output, feed_dict={input: some_data})
Explanation
The .pb format is the protocol buffer (protobuf) format, and in Tensorflow, this format is used to hold models. Protobufs are a general way to store data by Google that is much nicer to transport, as it compacts the data more efficiently and enforces a structure to the data. When used in TensorFlow, it's called a SavedModel protocol buffer, which is the default format when saving Keras/ Tensorflow 2.0 models. More information about this format can be found here and here.
For example, the following code (specifically, m.save), will create a folder called my_new_model, and save in it, the saved_model.pb, an assets/ folder, and a variables/ folder.
# first download a SavedModel from TFHub.dev, a website with models
m = tf.keras.Sequential([
hub.KerasLayer("https://tfhub.dev/google/imagenet/mobilenet_v2_130_224/classification/4")
])
m.build([None, 224, 224, 3]) # Batch input shape.
m.save("my_new_model") # defaults to save as SavedModel in tensorflow 2
In some places, you may also see .h5 models, which was the default format for TF 1.X. source
Extra information: In TensorFlow Lite, the library for running models on mobile and IoT devices, instead of protocol buffers, flatbuffers are used. This is what the TensorFlow Lite Converter converts into (.tflite format). This is another Google format which is also very efficient: it allows access to any part of the message without deserialization (unlike json, xml). For devices with less memory (RAM), it makes more sense to load what you need from the model file, instead of loading the entire thing into memory to deserialize it.
Loading SavedModels in TensorFlow 2
I noticed BiBi's answer to show loading models was popular, and there is a shorter way to do this in TF2:
import tensorflow as tf
model_path = "/path/to/directory/inception_v1_224_quant_20181026"
model = tf.saved_model.load(model_path)
Note,
the directory (i.e. inception_v1_224_quant_20181026) has to have a saved_model.pb or saved_model.pbtxt, otherwise the code will crash. You cannot specify the .pb path, specify the directory.
you might get TypeError: 'AutoTrackable' object is not callable for older models, fix here.
If you load a TF1 model, I found that I don't get any errors, but the loaded file doesn't behave as expected. (e.g. it doesn't have any functions on it, like predict)

Deploy Retrained inception model on Google cloud machine learning

I manage to retrain my specific classification model using the generic inception model following this tutorial. I would like now to deploy it on the google cloud machine learning following this steps.
I already managed to export it as MetaGraph but I can't manage to get the proper inputs and outputs.
Using it locally, my entry point to the graph is DecodeJpeg/contents:0 which is fed with a jpeg image in binary format. The output are my predictions.
The code I use locally (which is working) is:
softmax_tensor = sess.graph.get_tensor_by_name('final_result:0')
predictions = sess.run(softmax_tensor,{'DecodeJpeg/contents:0': image_data})
Should the input tensor be DecodeJpeg? What would be the changes I need to make if I would like to have a base64 image as input ?
I defined the output as:
outputs = {'prediction':softmax_tensor.name}
Any help is highly appreciated.
In your example, the input tensor is 'DecodeJpeg/contents:0', so you would have something like:
inputs = {'image': 'DecodeJpeg/contents:0')
outputs = {'prediction': 'final_result:0')
(Be sure to follow all of the instructions for preparing a model).
The model directory you intend to export should have files such as:
gs://my_bucket/path/to/model/export.meta
gs://my_bucket/path/to/model/checkpoint*
When you deploy your model, be sure to set gs://my_bucket/path/to/model as the deployment_uri.
To send an image to the service, as you suggest, you will need to base64 encode the image bytes. The body of your request should look like the following (note the 'tag', 'b64', indicating the data is base-64 encoded):
{'instances': [{'b64': base64.b64encode(image)}]}
We've now released a tutorial on how to retrain the Inception model, including instructions for how to deploy the model on the CloudML service.
https://cloud.google.com/blog/big-data/2016/12/how-to-train-and-classify-images-using-google-cloud-machine-learning-and-cloud-dataflow