gs_final, 4000 iterations) with 12000 iterations and a gaussian cap of 100,000 — the only change of the quality experiment that passed its review. Other changes (frame selection, water and motion-blur models, white balance, lossless crops) did not. The two turntables play in sync (same orbit and timing).
| metric | v1 gs_final | v2 gs_v2 | change |
|---|---|---|---|
| iterations | 4000 | 12000 | |
| gaussians | 20,805 | 30,063 | x1.44 |
| training time (optimisation) | 18 min | 71 min | |
| held-out frames (within 0.3 s of a training frame) | 12 (9) | 12 (9) | |
| LPIPS on the fish (lower = closer to the photo) | 0.1287 | 0.1207 | -0.0081 |
| PSNR full crop (dB) | 25.58 | 25.81 | +0.22 |
| PSNR on the fish mask (dB) | 23.52 | 23.82 | +0.30 |
| sharpness ratio render / photo, grain-robust (1 = as sharp as the photo) | 0.247 | 0.376 | x1.52 |
| sharpness ratio, raw | 0.158 | 0.299 | x1.89 |
| sharp match (photo detail reproduced in place) | 0.159 | 0.137 | -0.021 |
| IoU with the SAM mask | 0.878 | 0.877 | -0.002 |
Verdict: better. LPIPS -0.0081, grain-robust sharpness x1.52 (sharper). Differences below 0.0034 LPIPS or x1.12 sharpness are within the run-to-run noise of training.
Held-out frames: fixed per fish (work/quality_exp/<fish>/heldout.json), evaluated identically for both models (test-time fit of pose, colour and bending with the gaussians frozen). Both models were trained on all frames of the same data set, so held-out frames near a training frame favour both equally; this is a like-for-like comparison of the two recipes, not a generalisation test.
Family: Serranidae 84%, Labridae 9%, Lutjanidae 3% · agreement across crops 86% · 64 crops · bioclip-2.5 (hf-hub:imageomics/bioclip-2.5-vith14, open_clip, zero-shot)

| window | 68:00 – 72:00 |
| visits | 4: 69:53-69:58, 70:29-70:32, 70:45-70:47, 71:37-71:46 |
| frames (10 fps) detected / kept | 163 / 149 |
| valid poses (10 fps) | 161 |
| frames with background plate | 146 |
| median size | 124.0 px |
| 30 fps frames / valid poses | 439 / 412 |
| method | 4D GS, fins + bending + tail (30 fps) |
| model shown | v2 (gs_v2, quality experiment rollout) |
| iterations | 12000 |
| gaussians | 30063 |
| training time | 71 min |
| trainer validation PSNR full / masked | 26.4 / 24.5 dB |
| trainer validation IoU vs SAM mask | 0.902 |
| near-fish band PSNR (fins) | 26.0 dB |
| production status | done |
| visual note (curation) | dark grey grouper/snapper-like |






point_cloud.ply (canonical 3D gaussians) · poses_refined.json · model.pt (incl. per-frame 4D params) · species.json · previous version v1: gs_final point_cloud.ply