def get_scene_reprojection_errors(self) -> np.ndarray:
"""Get the scene reprojection errors for all 3D points and all associated measurements.
Returns:
Reprojection errors as a 1D numpy array.
"""
scene_reproj_errors: List[float] = []
for track in self._tracks:
track_errors, _ = reproj_utils.compute_track_reprojection_errors(
self._cameras, track)
scene_reproj_errors.extend(track_errors)
return np.array(scene_reproj_errors)
def get_scene_reprojection_errors(self) -> np.ndarray:
"""Get the scene reprojection errors for all 3D points and all associated measurements.
Returns:
Reprojection errors (measured in pixels) as a 1D numpy array.
"""
scene_reproj_errors: List[float] = []
for track in self._tracks:
track_errors, _ = reproj_utils.compute_track_reprojection_errors(self._cameras, track)
# passing an array argument to .extend() will convert the array to a list, and append its elements
scene_reproj_errors.extend(track_errors)
return np.array(scene_reproj_errors)
def __validate_track(self, track: SfmTrack, reproj_err_thresh: float) -> bool:
"""Validates a track based on reprojection errors and cheirality checks.
Args:
track: track with 3D landmark and measurements.
reproj_err_thresh: reprojection err threshold for each measurement.
Returns:
validity of the track.
"""
errors, avg_reproj_error = reproj_utils.compute_track_reprojection_errors(self._cameras, track)
# track is valid as all measurements have error below the threshold
cheirality_success = np.all(~np.isnan(errors))
return np.all(errors < reproj_err_thresh) and cheirality_success
def test_compute_track_reprojection_errors():
"""Ensure that reprojection error is computed properly within a track.
# For camera 0:
# [13] = [10,0,3] [1,0,0 | 0] [1]
# [24] = [0,10,4] * [0,1,0 | 0] *[2]
# [1] = [0, 0,1] [0,0,1 | 0] [1]
# [1]
# For camera 1:
# [-7] = [10,0,3] [1,0,0 |-2] [1]
# [44] = [0,10,4] * [0,1,0 | 2] *[2]
# [1] = [0, 0,1] [0,0,1 | 0] [1]
# [1]
"""
wTi0 = Pose3(Rot3.RzRyRx(0, 0, 0), np.zeros((3, 1)))
wTi1 = Pose3(Rot3.RzRyRx(0, 0, 0), np.array([2, -2, 0]))
f = 10
k1 = 0
k2 = 0
u0 = 3
v0 = 4
K0 = Cal3Bundler(f, k1, k2, u0, v0)
K1 = Cal3Bundler(f, k1, k2, u0, v0)
track_camera_dict = {
0: PinholeCameraCal3Bundler(wTi0, K0),
1: PinholeCameraCal3Bundler(wTi1, K1)
}
triangulated_pt = np.array([1, 2, 1])
track_3d = SfmTrack(triangulated_pt)
# in camera 0
track_3d.addMeasurement(idx=0, m=np.array([13, 24]))
# in camera 1
track_3d.addMeasurement(idx=1, m=np.array(
[-8, 43])) # should be (-7,44), 1 px error in each dim
errors, avg_track_reproj_error = reproj_utils.compute_track_reprojection_errors(
track_camera_dict, track_3d)
expected_errors = np.array([0, np.sqrt(2)])
np.testing.assert_allclose(errors, expected_errors)
assert avg_track_reproj_error == np.sqrt(2) / 2
def write_points(gtsfm_data: GtsfmData, images: List[Image],
save_dir: str) -> None:
"""Writes the point cloud data file in the COLMAP format.
Reference: https://colmap.github.io/format.html#points3d-txt
Args:
gtsfm_data: scene data to write.
images: list of all images for this scene, in order of image index
save_dir: folder to put the points3D.txt file in.
"""
os.makedirs(save_dir, exist_ok=True)
num_pts = gtsfm_data.number_tracks()
avg_track_length, _ = gtsfm_data.get_track_length_statistics()
file_path = os.path.join(save_dir, "points3D.txt")
with open(file_path, "w") as f:
f.write("# 3D point list with one line of data per point:\n")
f.write(
"# POINT3D_ID, X, Y, Z, R, G, B, ERROR, TRACK[] as (IMAGE_ID, POINT2D_IDX)\n"
)
f.write(
f"# Number of points: {num_pts}, mean track length: {np.round(avg_track_length, 2)}\n"
)
# TODO: assign unique indices to all keypoints (2d points)
point2d_idx = 0
for j in range(num_pts):
track = gtsfm_data.get_track(j)
r, g, b = image_utils.get_average_point_color(track, images)
_, avg_track_reproj_error = reproj_utils.compute_track_reprojection_errors(
gtsfm_data._cameras, track)
x, y, z = track.point3()
f.write(
f"{j} {x} {y} {z} {r} {g} {b} {np.round(avg_track_reproj_error, 2)} "
)
for k in range(track.numberMeasurements()):
i, uv_measured = track.measurement(k)
f.write(f"{i} {point2d_idx} ")
f.write("\n")