Voxel GC

[AndreiBarsan]

It seems that much of the noisy voxels in the reconstruction which stem from the noise in the depth estimation can be singled out by looking at their weight. In the following image, red areas correspond to voxels with weight = 1, i.e., which were only "seen" once:

The blue voxels are those with the maximum allowed weight (in our case, just 10, since the camera is moving quite quickly; the original InfiniTAM had ~100).

A quick and dirty solution would be to simply not render low-weight voxels, but that would also require modifications to the mesh generation algorithm.

A better solution would be to (efficiently) trim all voxels with age > k but weight < l, effectively regularizing the resulting reconstruction. This is what I'll be implementing in the end.

Subtasks:

• [x] Naive cleanup implementation: kernel to detect old, low-weight voxels, and clear them.
• [x] Compute empty blocks
• [x] Deallocate empty blocks
• [x] Graph to visualize empty block count; hopefully it will no longer constantly go down if we do this!
• [x] Clean up code (weird comments, TODOs, debug prints, etc.)
• [x] Apply voxel decay to reconstructed object instances as well.
• [x] Support "reap mode" which can operate on entire volumes.
• [x] Clean up after getting reap mode working.
• [x] Support deleting elements where collisions occur by looking up excess list entries correctly, and then performing a proper list deletion in the hash table, in addition to deallocating the VBA element.
• ~[ ] GUI button to "reap" currently active object.~

[AndreiBarsan]

May be worth implementing #19 first to simplify the bookkeeping.

[AndreiBarsan]

I implemented #19 and, together with it, added full support for voxel gc, complete with correct block freeing and recycling. Everything is done, except the dedicated GUI button, which is low-priority and should be a different issue anyway.