def angles_to_vec(ra, dec):
out = util.matrix_rotate_y(-ra) * \
util.matrix_rotate_x(-dec) * \
matrix([[0., 0., 1., 0]]).T
return out[:3, :]
def solve(world_points_in, image_points, annotate_images=None,
initial_matrices=None, initial_bd=0., initial_ps=3000.,
change_ps=False, change_bd=False, change_pos=True):
"""
Find a camera's orientation and pixel scale given a set of world
coordinates and corresponding set of camera coordinates.
world_points: Map of point names to triples corresponding with world
(x, y, z) coordinates.
image_points: Iterable of dicts mapping point names to pairs
corresponding with camera x, y coordinates. Coordinates
should be translated such that 0, 0 corresponds with the
centre of the image, and Y coordinates increase going top to
bottom. One element per source image.
annotate_images: Optional iterable of images to annotate with the fitted
points.
initial_matrices: Optional iterable of initial rotation matrices.
initial_bd: Optional initial barrel distortion to use.
initial_ps: Optional initial pixel scale to use.
change_ps: If True, allow the pixel scale (zoom) to be varied. Algorithm
can be unstable if initial guess is inaccurate.
change_bd: If True, allow the barrel distortion to be varied. Algorithm
can be unstable if initial guess is inaccurate.
change_pos: If True, allow the camera position to be varied.
Return: 4x4 matrix representing the camera's orientation, and a pixel
pixel scale.
"""
assert all(set(world_points_in.keys()) >= set(p.keys()) for p in image_points)
keys = [list(p.keys()) for p in image_points]
world_points = [hstack([matrix(list(world_points_in[k]) + [1.0]).T for k in sub_keys]) for sub_keys in keys]
image_points = hstack([hstack([matrix(p[k]).T for k in sub_keys]) for p, sub_keys in zip(image_points, keys)])
print image_points
if initial_matrices:
current_mat = [m for m in initial_matrices]
else:
current_mat = [util.matrix_trans(0.0, 0.0, 500.0)] * len(keys)
current_ps = initial_ps
current_bd = initial_bd
def camera_to_image(m, ps, bd):
def map_point(c):
px, py = calculate_barrel_distortion(bd, ps * c[0, 0] / c[0, 2], ps * c[0, 1] / c[0, 2])
return [px, py]
return matrix([map_point(c) for c in m.T]).T
last_err_float = None
while True:
# Calculate the Jacobian
camera_points = hstack([m * p for m, p in zip(current_mat, world_points)])
err = image_points - camera_to_image(camera_points, current_ps, current_bd)
J = make_jacobian(camera_points.T[:, :3], keys, current_ps, current_bd)
if not change_ps:
J = hstack([J[:, :-2], J[:, -1:]])
if not change_bd:
J = J[:, :-1]
if not change_pos:
for i in xrange(len(keys)):
J[:, (6 * i):(6 * i + 3)] = zeros((J.shape[0], 3))
# Invert the Jacobian and calculate the change in parameters.
# Limit angle changes to avoid chaotic behaviour.
err = err.T.reshape(2 * sum(len(sub_keys) for sub_keys in keys), 1)
param_delta = numpy.linalg.pinv(J) * (STEP_FRACTION * err)
# Calculate the error (as sum of squares), and abort if the error has
# stopped decreasing.
err_float = (err.T * err)[0, 0]
print "Error: %f" % err_float
print err
if last_err_float != None and abs(err_float - last_err_float) < ERROR_CUTOFF:
break
last_err_float = err_float
# Apply the parameter delta.
for i in xrange(len(keys)):
if change_pos:
current_mat[i] = util.matrix_trans(param_delta[6 * i + 0, 0], param_delta[6 * i + 1, 0], param_delta[6 * i + 2, 0]) * current_mat[i]
current_mat[i] = util.matrix_rotate_x(param_delta[6 * i + 3, 0]) * current_mat[i]
current_mat[i] = util.matrix_rotate_y(param_delta[6 * i + 4, 0]) * current_mat[i]
current_mat[i] = util.matrix_rotate_z(param_delta[6 * i + 5, 0]) * current_mat[i]
matrix_normalize(current_mat[i])
if change_ps:
current_ps += param_delta[6 * len(keys), 0]
if change_bd:
current_bd += param_delta[6 * len(keys) + 1, 0]
if annotate_images:
all_keys = list(world_points_in.keys())
all_world_points = hstack([matrix(list(world_points_in[k]) + [1.0]).T for k in all_keys])
for i, annotate_image in enumerate(annotate_images):
all_camera_points = current_mat[i] * all_world_points
util.draw_points(annotate_image,
dict(zip(all_keys, camera_to_image(all_camera_points, current_ps, current_bd).T)))
return current_mat, current_ps, current_bd