Add projective transformation / homography.

scikits/image/transform/tests/test_project.py

@@ -0,0 +1,21 @@
+import numpy as np
+from numpy.testing import assert_array_almost_equal
+
+from scikits.image.transform.project import _stackcopy, homography
+
+def test_stackcopy():
+    layers = 4
+    x = np.empty((3, 3, layers))
+    y = np.eye(3, 3)
+    _stackcopy(x, y)
+    for i in range(layers):
+        assert_array_almost_equal(x[...,i], y)
+
+def test_homography():
+    x = np.arange(9).reshape((3, 3)) + 1
+    theta = -np.pi/2
+    M = np.array([[np.cos(theta),-np.sin(theta),0],
+                  [np.sin(theta), np.cos(theta),2],
+                  [0,             0,            1]])
+    x90 = homography(x, M, order=1)
+    assert_array_almost_equal(x90, np.rot90(x))