def test_round_trip() -> None:
"""Test round trip of serialization, then de-serialization."""
bSc = Sim2(R=np.array([[0, 1], [1, 0]]), t=np.array([-5, 5]), s=0.1)
save_fpath = TEST_DATA_ROOT / "b_Sim2_c.json"
bSc.save_as_json(save_fpath=save_fpath)
bSc_ = Sim2.from_json(save_fpath)
assert bSc_ == bSc
def test_translation() -> None:
"""Ensure translation component is returned properly."""
R = np.array([[0, -1], [1, 0]])
t = np.array([1, 2])
bSa = Sim2(R=R, t=t, s=3.0)
expected_t = np.array([1, 2])
assert np.allclose(expected_t, bSa.translation)
def test_sim2_repr() -> None:
"""Ensure we can print the class, and obtain the correct string representation from __repr__."""
R = np.eye(2)
t = np.arange(2)
s = 10.5
aSb = Sim2(R, t, s)
print(aSb)
assert repr(aSb) == "Angle (deg.): 0.0, Trans.: [0. 1.], Scale: 10.5"
def test_cannot_set_zero_scale() -> None:
"""Ensure that an exception is thrown if Sim(2) scale is set to zero."""
R = np.eye(2)
t = np.arange(2)
s = 0.0
with pytest.raises(ZeroDivisionError) as e_info:
Sim2(R, t, s)
def test_matrix() -> None:
""" Ensure 3x3 matrix is formed correctly"""
bRa = np.array([[0, -1], [1, 0]])
bta = np.array([1, 2])
bsa = 3.0
bSa = Sim2(R=bRa, t=bta, s=bsa)
bSa_expected = np.array([[0, -1, 1], [1, 0, 2], [0, 0, 1 / 3]])
assert np.allclose(bSa_expected, bSa.matrix)
def test_transform_from_wrong_dims() -> None:
"""Ensure that 1d input is not allowed (row vectors are required, as Nx2)."""
bRa = np.eye(2)
bta = np.array([1, 2])
bsa = 3.0
bSa = Sim2(R=bRa, t=bta, s=bsa)
with pytest.raises(ValueError) as e_info:
val = bSa.transform_from(np.array([1.0, 3.0]))
def test_constructor() -> None:
"""Sim(2) to perform p_b = bSa * p_a"""
bRa = np.eye(2)
bta = np.array([1, 2])
bsa = 3.0
bSa = Sim2(R=bRa, t=bta, s=bsa)
assert isinstance(bSa, Sim2)
assert np.allclose(bSa.R_, bRa)
assert np.allclose(bSa.t_, bta)
assert np.allclose(bSa.s_, bsa)
def test_transform_from_backwards() -> None:
""" """
img_pts = np.array([[6, 4], [4, 6], [0, 0], [1, 7]])
expected_world_pts = np.array([[2, -1], [1, 0], [-1, -3], [-0.5, 0.5]])
scale = 0.5
wSimg = Sim2(R=np.eye(2), t=np.array([-2.0, -6.0]), s=scale)
world_pts = wSimg.transform_from(img_pts)
assert np.allclose(expected_world_pts, world_pts)
def test_transform_from_forwards() -> None:
""" """
expected_img_pts = np.array([[6, 4], [4, 6], [0, 0], [1, 7]])
world_pts = np.array([[2, -1], [1, 0], [-1, -3], [-0.5, 0.5]])
scale = 2.0
imgSw = Sim2(R=np.eye(2), t=np.array([1.0, 3.0]), s=scale)
img_pts = imgSw.transform_from(world_pts)
assert np.allclose(expected_img_pts, img_pts)
def test_save_as_json() -> None:
"""Ensure that JSON serialization of a class instance works correctly."""
bSc = Sim2(R=np.array([[0, 1], [1, 0]]), t=np.array([-5, 5]), s=0.1)
save_fpath = TEST_DATA_ROOT / "b_Sim2_c.json"
bSc.save_as_json(save_fpath=save_fpath)
bSc_dict = read_json_file(save_fpath)
assert bSc_dict["R"] == [0, 1, 1, 0]
assert bSc_dict["t"] == [-5, 5]
assert bSc_dict["s"] == 0.1
def test_matrix_homogenous_transform() -> None:
""" Ensure 3x3 matrix transforms homogenous points as expected."""
expected_img_pts = np.array([[6, 4], [4, 6], [0, 0], [1, 7]])
world_pts = np.array([[2, -1], [1, 0], [-1, -3], [-0.5, 0.5]])
scale = 2.0
imgSw = Sim2(R=np.eye(2), t=np.array([1.0, 3.0]), s=scale)
# convert to homogeneous
world_pts_h = np.hstack([world_pts, np.ones((4, 1))])
# multiply each (3,1) homogeneous point vector w/ transform matrix
img_pts_h = (imgSw.matrix @ world_pts_h.T).T
# divide (x,y,s) by s
img_pts = img_pts_h[:, :2] / img_pts_h[:, 2].reshape(-1, 1)
assert np.allclose(expected_img_pts, img_pts)
def test_transform_point_cloud() -> None:
"""Guarantee we can implement the SE(2) inferface, w/ scale=1.0
Sample 1000 random 2d rigid body transformations (R,t) and ensure
that 2d points are transformed equivalently with SE(2) or Sim(3) w/ unit scale.
"""
for sample in range(1000):
# generate random 2x2 rotation matrix
theta = np.random.rand() * 2 * np.pi
R = rotmat2d(theta)
t = np.random.randn(2)
pts_b = np.random.randn(25, 2)
aTb = SE2(copy.deepcopy(R), copy.deepcopy(t))
aSb = Sim2(copy.deepcopy(R), copy.deepcopy(t), s=1.0)
pts_a = aTb.transform_point_cloud(copy.deepcopy(pts_b))
pts_a_ = aSb.transform_point_cloud(copy.deepcopy(pts_b))
assert np.allclose(pts_a, pts_a_, atol=1e-7)
def test_from_matrix() -> None:
"""Ensure that classmethod can construct an object instance from a 3x3 numpy matrix."""
bRa = np.array([[0, -1], [1, 0]])
bta = np.array([1, 2])
bsa = 3.0
bSa = Sim2(R=bRa, t=bta, s=bsa)
bSa_ = Sim2.from_matrix(bSa.matrix)
# ensure we can reconstruct new instance from matrix
assert bSa == bSa_
# ensure generated class object has correct attributes
assert np.allclose(bSa_.rotation, bRa)
assert np.allclose(bSa_.translation, bta)
assert np.isclose(bSa_.scale, bsa)
# ensure generated class object has correct 3x3 matrix attribute
bSa_expected = np.array([[0, -1, 1], [1, 0, 2], [0, 0, 1 / 3]])
assert np.allclose(bSa_expected, bSa_.matrix)
def test_not_eq_scale() -> None:
""" Ensure object equality works properly (not equal scale). """
bSa = Sim2(R=np.eye(2), t=np.array([2, 1]), s=3.0)
bSa_ = Sim2(R=np.eye(2), t=np.array([2.0, 1.0]), s=1.0)
assert bSa != bSa_
def test_not_eq_rotation() -> None:
""" Ensure object equality works properly (not equal rotation). """
bSa = Sim2(R=np.eye(2), t=np.array([2, 1]), s=3.0)
bSa_ = Sim2(R=-1 * np.eye(2), t=np.array([2.0, 1.0]), s=3)
assert bSa != bSa_
def test_is_eq() -> None:
""" Ensure object equality works properly (are equal). """
bSa = Sim2(R=np.eye(2), t=np.array([1, 2]), s=3.0)
bSa_ = Sim2(R=np.eye(2), t=np.array([1.0, 2.0]), s=3)
assert bSa == bSa_
