Wie verwendet man Tensorflow tf.metrics.mean_iou?

Question

Ich versuche, die eingebaute mean_iou-Funktion von Tensorflow zu verwenden, um den IoU-Score für die semantische Segmentierung zu berechnen.

Mein Code ist:

#y_mask.shape == [batch_size, h * w, n_classes] 
#y_mask.shape == [batch_size, h * w, n_classes] 
iou = tf.metrics.mean_iou(tf.argmax(y_mask,2), tf.argmax(mask_,2), n_classes) 

Jedoch habe ich die folgende Fehler Spur bin immer:

tensorflow.python.framework.errors_impl.FailedPreconditionError: 

Attempting to use uninitialized value mean_iou/total_confusion 
_matrix 
     [[Node: mean_iou/AssignAdd = AssignAdd[T=DT_DOUBLE, _class=["loc:@mean_iou/total_confusion_matrix"], use_locking=false 
, _device="/job:localhost/replica:0/task:0/cpu:0"](mean_iou/total_confusion_matrix, mean_iou/confusion_matrix/SparseTensorDense 
Add)]] 

Caused by op u'mean_iou/AssignAdd', defined at: 
    File "sample_tf_ynet.py", line 207, in <module> 
    trainSeg() 
    File "sample_tf_ynet.py", line 166, in trainSeg 
    iou, cm_op = tf.metrics.mean_iou(tf.argmax(y_mask,2), tf.argmax(mask_,2), n_classes) 
    File "/home/meetshah1995/anaconda2/lib/python2.7/site-packages/tensorflow/python/ops/metrics_impl.py", line 782, in mean_iou 
    update_op = state_ops.assign_add(total_cm, current_cm) 
    File "/home/meetshah1995/anaconda2/lib/python2.7/site-packages/tensorflow/python/ops/gen_state_ops.py", line 75, in assign_ad 
d 
    use_locking=use_locking, name=name) 
    File "/home/meetshah1995/anaconda2/lib/python2.7/site-packages/tensorflow/python/framework/op_def_library.py", line 763, in a 
pply_op 
    op_def=op_def) 
    File "/home/meetshah1995/anaconda2/lib/python2.7/site-packages/tensorflow/python/framework/ops.py", line 2395, in create_op 
    original_op=self._default_original_op, op_def=op_def) 
    File "/home/meetshah1995/anaconda2/lib/python2.7/site-packages/tensorflow/python/framework/ops.py", line 1264, in __init__ 
    self._traceback = _extract_stack() 

FailedPreconditionError (see above for traceback): Attempting to use uninitialized value mean_iou/total_confusion_matrix 
     [[Node: mean_iou/AssignAdd = AssignAdd[T=DT_DOUBLE, _class=["loc:@mean_iou/total_confusion_matrix"], use_locking=false 
, _device="/job:localhost/replica:0/task:0/cpu:0"](mean_iou/total_confusion_matrix, mean_iou/confusion_matrix/SparseTensorDense 
Add)]] 

Bitte leite mich auf die richtige Anwendung dieser für die semantische Segmentierung.

Answer 1

Ich löste es durch

with tf.Session() as sess: 

    sess.run(tf.global_variables_initializer()) 
    sess.run(tf.local_variables_initializer())