How to make Image classifier in 5 min

In this ML lab, we will be using transfer learning, which means we are starting with a model that has been already trained on another problem. We will then be retraining it on a similar problem. Deep learning from scratch can take days, but transfer learning can be done in short order.
We are going to use the Inception v3 network. Inception v3 is a trained for the ImageNet Large Visual Recognition Challenge using the data from 2012, and it can differentiate between 1,000 different classes, like Dalmatian or dishwasher. We will use this same network, but retrain it to tell apart a small number of classes based on our own examples.

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Things we need:-

1. Linux desktop / VM
2. Docker
3. Tensorflow
4. Image Dataset (large)

What you will learn

1. How to install and run TensorFlow Docker images
2. How to use Python to train an image classifier
3. How to classify images with your trained classifier

Get Started

  In this ML Lab, you will learn how to install and run TensorFlow on a single machine, and will train a simple classifier to classify images of flowers. First you will need the large set of images of which you have to classify. We have 5 types of directory which contains different flowers. You can Download it from here or

cd $HOME
mkdir tf_files
cd tf_files
curl -O http://download.tensorflow.org/example_images/flower_photos.tgz
tar xzf flower_photos.tgz

# On OS X, see what's in the folder:
open flower_photos

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All directory contains images of flower and labels are important to classify. Add this directories into one main directory. In my case it is "Flower_photos".

Install Docker in Linux.

1. Log into your Ubuntu installation as a user with sudo privileges.
   
2. Update your APT package index.
   

   $ sudo apt-get update

3. Install Docker.
   

   $ sudo apt-get install docker-engine

4. Start the docker daemon.
   

   $ sudo service docker start 

5.  Verify that docker is installed correctly by running the hello-world image.
   

   $ sudo docker run hello-world
   

Install Tensorflow in Docker.

1. Start a terminal using Terminal.app

          docker run -it gcr.io/tensorflow/tensorflow:latest-devel

        Check to see if your TensorFlow works by invoking Python from the       container's command line (you'll see "root@xxxxxxx#"):

     2. Exit docker by "ctrl+d".

    2.Start Docker with local files available

The TensorFlow Docker image doesn't contain the flower data, so we'll make it available by linking it in virtually.

docker run -it -v $HOME/tf_files:/tf_files  gcr.io/tensorflow/tensorflow:latest-devel

At the Docker prompt, you can see it's linked as a top level directory.

• ls /tf_files/
  # Should see: flower_photos  flower_photos.tgz   

  Retrieving the training code

  The Docker image you are using contains the latest GitHub TensorFlow tools, but not every last sample. You need to retrieve the full sample set this way.
• cd /tensorflow
• git pull  

1. (Re)training Inception

   At this point, we have a trainer, we have data, so let's train! We will train the Inception v3 network.
   As noted in the introduction, Inception is a huge image classification model with millions of parameters that can differentiate a large number of kinds of images. We're only training the final layer of that network, so training will end in a reasonable amount of time.
   Start your image retraining with one big command:
   

   # In Docker
   python tensorflow/examples/image_retraining/retrain.py \
   --bottleneck_dir=/tf_files/bottlenecks \
   --how_many_training_steps 500 \
   --model_dir=/tf_files/inception \
   --output_graph=/tf_files/retrained_graph.pb \
   --output_labels=/tf_files/retrained_labels.txt \
   --image_dir /tf_files/flower_photos

   If you have plenty of time remove

   how_many_training_steps 500

   Using the Retrained Model

   The retraining script will write out a version of the Inception v3 network with a final layer retrained to your categories to tf_files/output_graph.pb and a text file containing the labels to tf_files/output_labels.txt.
   These files are both in a format that the C++ and Python image classification examples can use, so you can start using your new model immediately.
   

   Classifying an image

   Here is Python that loads your new graph file and predicts with it.
   

   label_image.py

     import tensorflow as tf, sys
   
   image_path = sys.argv[1]
   
   # Read in the image_data
   image_data = tf.gfile.FastGFile(image_path, 'rb').read()
   
   # Loads label file, strips off carriage return
   label_lines = [line.rstrip() for line
                      in tf.gfile.GFile("/tf_files/retrained_labels.txt")]
   
   # Unpersists graph from file
   with tf.gfile.FastGFile("/tf_files/retrained_graph.pb", 'rb') as f:
       graph_def = tf.GraphDef()
       graph_def.ParseFromString(f.read())
       _ = tf.import_graph_def(graph_def, name='')
   
   with tf.Session() as sess:
       # Feed the image_data as input to the graph and get first prediction
       softmax_tensor = sess.graph.get_tensor_by_name('final_result:0')
      
       predictions = sess.run(softmax_tensor, \
                {'DecodeJpeg/contents:0': image_data})
      
       # Sort to show labels of first prediction in order of confidence
       top_k = predictions[0].argsort()[-len(predictions[0]):][::-1]
      
       for node_id in top_k:
           human_string = label_lines[node_id]
           score = predictions[0][node_id]
           print('%s (score = %.5f)' % (human_string, score))

 Or you can download it:-

• curl -L https://goo.gl/tx3dqg > $HOME/tf_files/label_image.py 

Restart your Docker image:

docker run -it -v $HOME/tf_files:/tf_files  gcr.io/tensorflow/tensorflow:latest-devel 

Now, run the Python file you created, first on a daisy:

# In Docker
python /tf_files/label_image.py /tf_files/flower_photos/daisy/21652746_cc379e0eea_m.jpg

• Thank you guys, In my next post I will show how to use tensorflow with Webcam images using opencv