Question about Unsupervised LiDAR Densification

[sky-fly97]

Hello, I have two questions to ask for advice.

1. In simple terms, is the task of this article to upsample a given point cloud? From one input can be sampled to get different styles of virtaual point clouds, thus expanding the dataset?
2. How to understand Unsupervised LiDAR Densification, with a 4-beam point cloud as input, and supervision is 16-beam, so where is the unsupervised representation?

[vzyrianov]

Hello Xiangchao, thank you for checking out our paper!

1. The task of the article is to learn the distribution of LiDAR data with a diffusion model. Once the distribution is learned, it is possible to generate unconditional samples or use guided diffusion for conditional sampling (e.g., conditioning on 4 beams to upsample to 64 beam).

2. There is no supervision for the densification task. Only the sampling process is modified. In the results, we upsample 4 -> 64 and 16 -> 64 by using a form of classifier guidance.