import tensorflow as tf

        targets_dx = (gt_boxes_urx - bboxes_urx)/(bboxes_width * variances[0])
        targets_dy = (gt_boxes_ury - bboxes_ury)/(bboxes_height * variances[0])

        targets_dw = tf.log(gt_boxes_width / bboxes_width) / variances[1]
        targets_dh = tf.log(gt_boxes_height / bboxes_height) / variances[1]

