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 | 17,120 | 25,211 | x1.47 |
| training time (optimisation) | 18 min | 75 min | |
| held-out frames (within 0.3 s of a training frame) | 38 (10) | 38 (10) | |
| LPIPS on the fish (lower = closer to the photo) | 0.1626 | 0.1479 | -0.0147 |
| PSNR full crop (dB) | 26.15 | 26.42 | +0.27 |
| PSNR on the fish mask (dB) | 22.71 | 23.09 | +0.38 |
| sharpness ratio render / photo, grain-robust (1 = as sharp as the photo) | 0.208 | 0.353 | x1.70 |
| sharpness ratio, raw | 0.092 | 0.286 | x3.12 |
| sharp match (photo detail reproduced in place) | 0.132 | 0.178 | +0.047 |
| IoU with the SAM mask | 0.882 | 0.875 | -0.006 |
Verdict: better. LPIPS -0.0147, grain-robust sharpness x1.70 (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: Balistidae 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 | 40:00 – 48:00 |
| visits | 11: 42:07-42:10, 42:33-42:39, 43:15-43:22, 43:49-43:53, 44:07-44:20, 44:47-44:55, 45:02-45:18, 45:56-46:02, 46:12-46:14, 46:33-46:36, 47:41-47:58 |
| frames (10 fps) detected / kept | 742 / 708 |
| valid poses (10 fps) | 696 |
| frames with background plate | 708 |
| median size | 121.0 px |
| 30 fps frames / valid poses | 723 / 575 |
| method | 4D GS, fins + bending + tail (30 fps) |
| model shown | v2 (gs_v2, quality experiment rollout) |
| iterations | 12000 |
| gaussians | 25211 |
| training time | 75 min |
| trainer validation PSNR full / masked | 27.1 / 21.1 dB |
| trainer validation IoU vs SAM mask | 0.872 |
| near-fish band PSNR (fins) | 27.2 dB |
| production status | done |
| visual note (curation) | orange-lined triggerfish, Balistapus undulatus likely (a few tang frames) |






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