Using the Mapillary API, is there is a way to obtain the set of images that were optimised together (their 6-DoF poses and 3D map points) within Mapillary’s Structure-from-Motion pipeline?
From the documentation, the fields sfm_cluster and merge_cc may be what I am looking for. However, they differ in what they represent. From the docs:
- merge_cc - int, ID of the connected component of images that were aligned together.
- sfm_cluster - { id: string, url: string } - URL to the point cloud data in JSON and compressed by zlib. See the example below
Could you please confirm if my understanding of them is correct?
- regarding
merge_cc: a local SfM reconstruction corresponds to just onemerge_ccvalue. Thus, the 3D geometry (camera poses and 3D points) corresponding to images sharing the samemerge_ccvalue was optimised together and no othermerge_ccvalue exists for images participating in the same reconstruction. - regarding
sfm_cluster: a local SfM reconstruction may contain multiplesfm_clustervalues.sfm_clusterthus refers to partial local SfM reconstructions.
Any help in understanding this is really appreciated!
The following shows examples of image locations colored by merge_cc or sfm_cluster. Multiple sequences can have images with a shared merge_cc/sfm_cluster, which might indicate that a joint optimization has been done across these sequences. However, it seems that for sfm_cluster there is a stricter criterion for assigning images to the same value.
