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 | 16,981 | 25,011 | x1.47 |
| training time (optimisation) | 20 min | 72 min | |
| held-out frames (within 0.3 s of a training frame) | 12 (12) | 12 (12) | |
| LPIPS on the fish (lower = closer to the photo) | 0.0923 | 0.0850 | -0.0073 |
| PSNR full crop (dB) | 28.22 | 28.27 | +0.06 |
| PSNR on the fish mask (dB) | 27.18 | 27.58 | +0.39 |
| sharpness ratio render / photo, grain-robust (1 = as sharp as the photo) | 0.588 | 0.712 | x1.21 |
| sharpness ratio, raw | 0.290 | 0.391 | x1.35 |
| sharp match (photo detail reproduced in place) | 0.622 | 0.702 | +0.079 |
| IoU with the SAM mask | 0.883 | 0.879 | -0.003 |
Verdict: better. LPIPS -0.0073, grain-robust sharpness x1.21 (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: Labridae 100%, Scaridae 0%, Serranidae 0% · agreement across crops 100% · 64 crops · bioclip-2.5 (hf-hub:imageomics/bioclip-2.5-vith14, open_clip, zero-shot)

| window | 68:00 – 72:00 |
| visits | 8: 68:03-68:06, 68:32-68:34, 68:36-68:39, 69:31-69:33, 69:36-69:38, 69:53-69:55, 71:33-71:36, 71:52-72:00 |
| frames (10 fps) detected / kept | 221 / 209 |
| valid poses (10 fps) | 209 |
| frames with background plate | 210 |
| median size | 134.0 px |
| 30 fps frames / valid poses | 668 / 588 |
| method | 4D GS, fins + bending + tail (30 fps) |
| model shown | v2 (gs_v2, quality experiment rollout) |
| iterations | 12000 |
| gaussians | 25011 |
| training time | 72 min |
| trainer validation PSNR full / masked | 29.0 / 22.5 dB |
| trainer validation IoU vs SAM mask | 0.934 |
| near-fish band PSNR (fins) | 29.2 dB |
| production status | done |
| visual note (curation) | banded wrasse (pale vertical bar) |






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