I think it would be immensely helpful to the Tensorflow community if there was a well-documented solution to the crucial task of testing a single new image against the model created by the convnet in the CIFAR-10 tutorial.
I may be wrong, but this critical step that makes the trained model usable in practice seems to be lacking. There is a "missing link" in that tutorial—a script that would directly load a single image (as array or binary), compare it against the trained model, and return a classification.
Prior answers give partial solutions that explain the overall approach, but none of which I've been able to implement successfully. Other bits and pieces can be found here and there, but unfortunately haven't added up to a working solution. Kindly consider the research I've done, before tagging this as duplicate or already answered.
Tensorflow: how to save/restore a model?
Unable to restore models in tensorflow v0.8
https://gist.github.com/nikitakit/6ef3b72be67b86cb7868
The most popular answer is the first, in which @RyanSepassi and @YaroslavBulatov describe the problem and an approach: one needs to "manually construct a graph with identical node names, and use Saver to load the weights into it". Although both answers are helpful, it is not apparent how one would go about plugging this into the CIFAR-10 project.
A fully functional solution would be highly desirable so we could port it to other single image classification problems. There are several questions on SO in this regard that ask for this, but still no full answer (for example Load checkpoint and evaluate single image with tensorflow DNN).
I hope we can converge on a working script that everyone could use.
The below script is not yet functional, and I'd be happy to hear from you on how this can be improved to provide a solution for single-image classification using the CIFAR-10 TF tutorial trained model.
Assume all variables, file names etc. are untouched from the original tutorial.
New file: cifar10_eval_single.py
import cv2
import tensorflow as tf
FLAGS = tf.app.flags.FLAGS
tf.app.flags.DEFINE_string('eval_dir', './input/eval',
"""Directory where to write event logs.""")
tf.app.flags.DEFINE_string('checkpoint_dir', './input/train',
"""Directory where to read model checkpoints.""")
def get_single_img():
file_path = './input/data/single/test_image.tif'
pixels = cv2.imread(file_path, 0)
return pixels
def eval_single_img():
# below code adapted from @RyanSepassi, however not functional
# among other errors, saver throws an error that there are no
# variables to save
with tf.Graph().as_default():
# Get image.
image = get_single_img()
# Build a Graph.
# TODO
# Create dummy variables.
x = tf.placeholder(tf.float32)
w = tf.Variable(tf.zeros([1, 1], dtype=tf.float32))
b = tf.Variable(tf.ones([1, 1], dtype=tf.float32))
y_hat = tf.add(b, tf.matmul(x, w))
saver = tf.train.Saver()
with tf.Session() as sess:
sess.run(tf.initialize_all_variables())
ckpt = tf.train.get_checkpoint_state(FLAGS.checkpoint_dir)
if ckpt and ckpt.model_checkpoint_path:
saver.restore(sess, ckpt.model_checkpoint_path)
print('Checkpoint found')
else:
print('No checkpoint found')
# Run the model to get predictions
predictions = sess.run(y_hat, feed_dict={x: image})
print(predictions)
def main(argv=None):
if tf.gfile.Exists(FLAGS.eval_dir):
tf.gfile.DeleteRecursively(FLAGS.eval_dir)
tf.gfile.MakeDirs(FLAGS.eval_dir)
eval_single_img()
if __name__ == '__main__':
tf.app.run()
