import tensorflow as tf

    # embedding
    dists = l2(self.embedding_test[:-1] - self.embedding_test[1:])
    self.dist = dists
    metrics = []

    metrics.append(tf.summary.histogram('point_distance', dists))
    metrics.append(tf.summary.scalar('training/trajectory_length', tf.reduce_sum(dists)))
    self.blur_ph = tf.placeholder(dtype=tf.float32)
    metrics.append(tf.summary.scalar('training/blur_sigma', self.blur_ph))

    pred = self.embedding_test[1:-1]*2 - self.embedding_test[0:-2]
    pred_error = l2(pred - self.embedding_test[2:])
