16.65. sfm_submap

The sfm_submap program takes as input a Structure-from-Motion (SfM) map in .nvm format, as produced by theia_sfm (Section 16.72) or rig_calibrator (Section 16.60), and extracts from it a submap for a desired subset of the images.

It works with .nvm files in which the keypoints were shifted relative to the optical center (which is the default for both theia_sfm and rig_calibrator) or not (as can be saved by rig_calibrator, see Section 16.60.5). This property is preserved by this tool.

The produced map can be visualized in stereo_gui (Section 16.70.9.4). For now, if the features are shifted relative to the optical center, the user must produce the list of shifts, as detailed at the above link, for the features to be plotted correctly. It is suggested to always use rig_calibrator with the option --save_nvm_no_shift to create an unshifted file to start with.

See also sfm_merge (Section 16.63), a tool for merging maps.

16.65.1. Examples

Example 1 (specify the images to have in the submap on the command line):

sfm_submap -input_map in_map.nvm -output_map out_map.nvm \
  image1.jpg image2.jpg ...

Example 2 (let those images be in a file, one per line):

sfm_submap -input_map in_map.nvm -output_map out_map.nvm \
  -image_list list.txt

The images in the list not present in the input map will be ignored.

16.65.2. Command-line options for sfm_submap

--input_map The input map, in .nvm format. Type: string. Default: “”.

--output_map The output map, in .nvm format. Type: string. Default: “”.

--image_list A file having the names of the images to be included in

the submap, one per line.