Can't complete reconstruction with 10 RGB-D images.[Open3D WARNING] Write PLY failed: mesh has 0 vertices.

### Checklist

- [X] I have searched for [similar issues](https://github.com/isl-org/Open3D/issues).
- [X] For Python issues, I have tested with the [latest development wheel](http://www.open3d.org/docs/latest/getting_started.html#development-version-pip).
- [X] I have checked the [release documentation](http://www.open3d.org/docs/release/) and the [latest documentation](http://www.open3d.org/docs/latest/) (for `master` branch).

### My Question

I want to do 3D reconstruction using RGB-D images.I followed the document [Docs>Rconstruction System>System Overview](http://open3d.org/docs/release/tutorial/reconstruction_system/system_overview.html)
The RGB-D datasets that I provided contains 10 RGB-D pairs from multi-view. And the format of my dataset is the same as the example provided in the document. But when I finish my process of running run_system.py, I can't get my .ply mesh, it says **[Open3D WARNING] Write PLY failed: mesh has 0 vertices.** and **[Open3D WARNING] PoseGraph read JSON failed: empty edges.**.
What should I do to solve this problem?Should I provide more images?