import tensorflow as tf

        input_image = tf.constant(input_image, dtype=tf.float32)
        output = MODEL.build_server_graph(FLAGS, input_image)
        output = (output + 1.) * 127.5
        output = tf.reverse(output, [-1])
        output = tf.saturate_cast(output, tf.uint8)
        # load pretrained model
        vars_list = tf.get_collection(tf.GraphKeys.GLOBAL_VARIABLES)
        assign_ops = []
