Voxels

The voxel grid

The first data representation we introduce is the most straightforward one: the voxel grid. Essentially, the voxel grid approach is very similar to the dense 2D grid structure we see in images. The only difference is the extension into a 3^rd spatial dimension. They are also called volumes, and PyTorch3D has its own Volumes class.

Rather than representing visual data (e.g., light) projected onto a 2D plane, voxel grids are a discrete data structure directly representing the 3D physical space. Instead of 2D pixels, which bin light within a rectangular receptive field, we have voxels, which are the 3D analog of pixels. Images can represent more than just color; images can represent depth from time-of-flight sensors or LiDARLiDAR, or Light Detection and Ranging, is a remote sensing technology that uses laser light to measure depth or distances with high precision. , radiation measurements from PET, SPECT, and CT scanning, and more. Likewise, voxels in a 3D space can represent density, probability, and color, just to name a few.