Commit 4263379a authored by Luke Campagnola's avatar Luke Campagnola
Browse files

added test for solve3DTransform

parent 0bc923b7
......@@ -568,16 +568,25 @@ def transformCoordinates(tr, coords, transpose=False):
def solve3DTransform(points1, points2):
"""
Find a 3D transformation matrix that maps points1 onto points2.
Points must be specified as a list of 4 Vectors.
Points must be specified as either lists of 4 Vectors or
(4, 3) arrays.
"""
import numpy.linalg
A = np.array([[points1[i].x(), points1[i].y(), points1[i].z(), 1] for i in range(4)])
B = np.array([[points2[i].x(), points2[i].y(), points2[i].z(), 1] for i in range(4)])
pts = []
for inp in (points1, points2):
if isinstance(inp, np.ndarray):
A = np.empty((4,4), dtype=float)
A[:,:3] = inp[:,:3]
A[:,3] = 1.0
else:
A = np.array([[inp[i].x(), inp[i].y(), inp[i].z(), 1] for i in range(4)])
pts.append(A)
## solve 3 sets of linear equations to determine transformation matrix elements
matrix = np.zeros((4,4))
for i in range(3):
matrix[i] = numpy.linalg.solve(A, B[:,i]) ## solve Ax = B; x is one row of the desired transformation matrix
## solve Ax = B; x is one row of the desired transformation matrix
matrix[i] = numpy.linalg.solve(pts[0], pts[1][:,i])
return matrix
......
import pyqtgraph as pg
import numpy as np
from numpy.testing import assert_array_almost_equal, assert_almost_equal
np.random.seed(12345)
def testSolve3D():
p1 = np.array([[0,0,0,1],
[1,0,0,1],
[0,1,0,1],
[0,0,1,1]], dtype=float)
# transform points through random matrix
tr = np.random.normal(size=(4, 4))
tr[3] = (0,0,0,1)
p2 = np.dot(tr, p1.T).T[:,:3]
# solve to see if we can recover the transformation matrix.
tr2 = pg.solve3DTransform(p1, p2)
assert_array_almost_equal(tr[:3], tr2[:3])
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