SfMTransform

Description

Transform/Scale SfM using given transformation, cameras, landmarks, markers. Can be used to scale SfM to real-world size.

Settings

Name

Description

Input

SfMData file

Transformation Method

Transformation method:

  • transformation: Apply a given transformation

  • auto_from_cameras: Use cameras

  • auto_from_landmarks: Fit all landmarks into a box [-1,1]

  • from_single_camera: Use a specific camera as the origin of the coordinate system

  • from_markers: Align specific markers to custom coordinates

  • from_gps: Align using the gps metadata (EXIF)

Transformation

Required only for ‘transformation’ and ‘from_single_camera’ methods:

  • transformation: Align [X,Y,Z] to +Y-axis, rotate around Y by R deg, scale by S; syntax: X,Y,Z;R;S

  • from_single_camera: Camera UID or image filename

Landmarks Describer Types

Image describer types used to compute the mean of the point cloud. (only for “landmarks” method). (‘sift’, ‘sift_float’, ‘sift_upright’, ‘akaze’, ‘akaze_liop’, ‘akaze_mldb’, ‘cctag3’, ‘cctag4’, ‘sift_ocv’, ‘akaze_ocv’)

Additional Scale

Additional scale to apply. (0.0-100.0, default 1.0)

Markers

Markers alignment points

Scale

Apply scale transformation.

Rotation

Apply rotation transformation.

Translation

Apply translation transformation.

Verbose Level

verbosity level (fatal, error, warning, info, debug, trace).

Details

Transformation Method: transformation

  • transformation as X,Y,Z;R;S

    Align [X,Y,Z] to +Y-axis, rotate around Y by R deg, scale by S. It aligns and scales the point cloud by explicitly specifying the scale and “up” vector [X,Y,Z] in the point cloud’s reference system. The rotation is computed such that the specified [X,Y,Z] vector is aligned with [0,1,0] after the transformation.

    The use-case to allow the user to derive the desired rotation by interactive manipulation of the point cloud in a 3D program (Meshlab), read off the transformation parameters and transform the point cloud. https://github.com/alicevision/AliceVision/pull/206

  • from single camera as UID or image filename

    Sets a specific camera as origin and applies correct orientation if possible Provide Camera UID or image filename

  • auto_from_landmarks as DescriberType(s)

    Compute the scale that brings all the selected landmarks type in a the unit box [-1, 1]