--- a
+++ b/DESS/utils.py
@@ -0,0 +1,53 @@
+# ==============================================================================
+# Copyright (C) 2023 Haresh Rengaraj Rajamohan, Tianyu Wang, Kevin Leung, 
+# Gregory Chang, Kyunghyun Cho, Richard Kijowski & Cem M. Deniz 
+#
+# This file is part of OAI-MRI-TKR
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published
+# by the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+# ==============================================================================
+import random
+import numpy as np
+import math
+
+def angle_axis_to_rotation_matrix(angle,axis):
+
+    '''
+    :param angle: angle of rotation
+    :param axis: Axis 0f rotation
+    :return: Rotation Matrix
+    '''
+
+    A = np.outer(axis,axis)
+    B = np.zeros((3,3),dtype=float)
+    B[0,1] = -1*axis[-1]
+    B[0,2] = axis[-2]
+    B[1,2] = axis[0]
+    B = B - B.transpose()
+    R = math.cos(angle)+np.eye(3)+ math.sin(angle)*B + (1-math.cos(angle))*A
+    return R
+
+
+def generating_random_rotation_matrix():
+    '''
+    :return: random rotation matrix, axis of rotation, angle of rotation
+    random rotation matrix is selected in such a way that the axis of rotation is uinformally distributed on a unit
+    sphere and the angle is uniformally distributed.
+    '''
+
+    guassian_vector = [random.gauss(mu=0, sigma=1), random.gauss(mu=0, sigma=1), random.gauss(mu=0, sigma=1)]
+    axis_of_rotation = list(np.array(guassian_vector) / np.linalg.norm(x=np.array(guassian_vector)))
+    angle_of_rotation = 2 * math.pi * random.uniform(0, 1)
+    rotation_matrix = angle_axis_to_rotation_matrix(angle=angle_of_rotation, axis=axis_of_rotation)
+    return rotation_matrix, axis_of_rotation, angle_of_rotation