in 04_detect_segment/utils_box.py [0:0]
def rot90(rois, tile_size, k=1):
rotation = tf.constant([[0.0, -1.0], [1.0, 0.0]], tf.float32)
rot_mat = tf.constant([[1.0, 0.0], [0.0, 1.0]], tf.float32)
k = k % 4 # always a positive number in python
for _ in range(k):
rot_mat = tf.matmul(rot_mat, rotation)
return rotate(rois, tile_size, rot_mat)