16.66. theia_sfm

The theia_sfm program is a wrapper around the Theia Structure-from-Motion (SfM) software, to adapt it to work with rig_calibrator (Section 16.55). See that page for an example.

ASP offers another wrapper around Theia, namely camera_solve (Section 16.12), whose aim is to work with ASP’s bundle_adjust program (Section 16.5).

As for rig_calibrator, the images are stored in subdirectories corresponding to sensor name, but it is not assumed that the image files (without directory name) represent a timestamp. So, an image name can be of the form: dir/sensor/string.png.

16.66.1. Usage

theia_sfm --rig_config <rig config> [images]  \
  [--theia_flags <flag file>] --out_dir <out dir>

16.66.2. Examples

The input images can be specified as:

wildcards:

theia_sfm --rig_config rig_input/rig_config.txt        \
  --images 'rig_input/cam1/*.tif rig_input/cam2/*.tif' \
  --out_dir rig_theia

in a list:

ls rig_input/cam*/*.jpg > image_list.txt
theia_sfm --rig_config rig_input/rig_config.txt        \
  --image_list image_list.txt                          \
  --out_dir rig_theia

on the command line:

theia_sfm --rig_config rig_input/rig_config.txt        \
  rig_input/cam1/image1.png rig_input/cam2/image2.png  \
  --out_dir rig_theia

16.66.3. Visualization

The created camera poses can be visualized as:

view_reconstruction --reconstruction out_dir/reconstruction-0

The .nvm file can be visualized with stereo_gui (Section 16.64.9.4).

16.66.4. Manipulating SfM solutions

This tool produces an SfM solution with a name like out_dir/cameras.nvm. Several of these can be merged into a larger reconstruction with the sfm_merge (Section 16.58) program. Portions can be extracted with sfm_submap (Section 16.59).

16.66.4.1. Command-line options for theia_sfm

--rig_config <string (default: “”)>

Rig configuration file.

--images <string (default: “”)>

Images, as individual wildcards. Example: 'dir/cam1/*tif dir/cam2/*tif'.

--image_list <string (default: “”)>

Use the images from this list, instead of setting --images. Images must be separated by a newline.

--theia_flags <string (default: “”)>

The flags to pass to Theia. By default, the file share/theia_flags.txt in the software distribution is used.

--out_dir <string (default: “”)>

The output directory (only the ‘cameras.nvm’ file in it is needed afterwards).

-h, --help

Show this help message and exit.