def tcoords_pixel_scaled(self):
r"""
Returns a PointCloud that is modified to be suitable for directly
indexing into the pixels of the texture (e.g. for manual mapping
operations). The resulting tcoords behave just like image landmarks
do:
>>> texture = texturedtrimesh.texture
>>> tc_ps = texturedtrimesh.tcoords_pixel_scaled()
>>> pixel_values_at_tcs = texture[tc_ps[: ,0], tc_ps[:, 1]]
The operations that are performed are:
- Flipping the origin from bottom-left to top-left
- Scaling the tcoords by the image shape (denormalising them)
- Permuting the axis so that
Returns
-------
tcoords_scaled : :class:`menpo.shape.PointCloud`
A copy of the tcoords that behave like Image landmarks
"""
scale = Scale(np.array(self.texture.shape)[::-1])
tcoords = self.tcoords.points.copy()
# flip the 'y' st 1 -> 0 and 0 -> 1, moving the axis to upper left
tcoords[:, 1] = 1 - tcoords[:, 1]
# apply the scale to get the units correct
tcoords = scale.apply(tcoords)
# flip axis 0 and axis 1 so indexing is as expected
tcoords = tcoords[:, ::-1]
return PointCloud(tcoords)
def chain_compose_before_tps_test():
a = PointCloud(np.random.random([10, 2]))
b = PointCloud(np.random.random([10, 2]))
tps = TPS(a, b)
t = Translation([3, 4])
s = Scale([4, 2])
chain = TransformChain([t, s])
chain_mod = chain.compose_before(tps)
points = PointCloud(np.random.random([10, 2]))
manual_res = tps.apply(s.apply(t.apply(points)))
chain_res = chain_mod.apply(points)
assert(np.all(manual_res.points == chain_res.points))
