import tensorflow as tf

      channels = im.get_shape().as_list()[4]

      x = tf.to_float(x)
      y = tf.to_float(y)
      z = tf.to_float(z)
      depth_f = tf.to_float(depth)
      height_f = tf.to_float(height)
      width_f = tf.to_float(width)
      # Number of disparity interpolated.
      out_depth = out_size[0]
      out_height = out_size[1]
      out_width = out_size[2]
      zero = tf.zeros([], dtype='int32')
      # 0 <= z < depth, 0 <= y < height & 0 <= x < width.
