Yellowfin hind · w40_fish1

Cephalopholis hemistiktos · Serranidae · 85% · high reconstructed model: fair

Reviewer: very dark, faint model; outline right

Where it comes from

Original video (longest visit, 44:06-44:26), the selected fish boxed

Tracking: real frame + crop + 3D render at the estimated pose, species overlay

3D and 4D model

loading 3D gaussians…

Interactive canonical 3D gaussians (drag to orbit, scroll to zoom). This is the rest pose shared by every frame; the 4D part is the per-frame bending / tail motion shown on the right.

4D: canonical model replaying the learned body bending and tail beat

3D turntable of the canonical model

Previous version (v1) vs v2

v2 = the same 30 fps data and trainer as v1 (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.

v1 (previous version): gs_final, 4000 iterations

v2: gs_v2, 12000 iterations

The two turntables play in sync (same orbit and timing).

metric	v1 gs_final	v2 gs_v2	change
iterations	4000	12000
gaussians	15,329	20,800	x1.36
training time (optimisation)	20 min	75 min
held-out frames (within 0.3 s of a training frame)	45 (0)	45 (0)
LPIPS on the fish (lower = closer to the photo)	0.1806	0.1758	-0.0047
PSNR full crop (dB)	22.38	22.47	+0.09
PSNR on the fish mask (dB)	18.79	18.89	+0.09
sharpness ratio render / photo, grain-robust (1 = as sharp as the photo)	0.109	0.136	x1.25
sharpness ratio, raw	0.050	0.071	x1.43
sharp match (photo detail reproduced in place)	0.013	0.017	+0.004
IoU with the SAM mask	0.893	0.895	+0.003

Verdict: better. LPIPS -0.0047, grain-robust sharpness x1.25 (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.

Poster

Species

Yellowfin hind Cephalopholis hemistiktos Serranidae

85.2%

Redmouth grouper Aethaloperca rogaa Serranidae

4.5%

Bluestreak cleaner wrasse Labroides dimidiatus Labridae

1.5%

Yellow-edged lyretail Variola louti Serranidae

1.3%

Vermilion hind Cephalopholis oligosticta Serranidae

1.2%

Family: Serranidae 93%, Labridae 4%, Scaridae 1% · agreement across crops 94% · 64 crops · bioclip-2.5 (hf-hub:imageomics/bioclip-2.5-vith14, open_clip, zero-shot)

Data and reconstruction

window	40:00 – 48:00
visits	11: 40:08-40:11, 40:42-40:51, 41:00-41:00, 41:04-41:46, 41:49-42:08, 42:50-42:54, 43:02-44:24, 44:26-44:52, 44:55-46:32, 46:46-47:12, 47:22-48:00
frames (10 fps) detected / kept	3261 / 3259
valid poses (10 fps)	3234
frames with background plate	2753
median size	134.0 px
30 fps frames / valid poses	721 / 706
method	4D GS, fins + bending + tail (30 fps)
model shown	v2 (gs_v2, quality experiment rollout)
iterations	12000
gaussians	20800
training time	75 min
trainer validation PSNR full / masked	24.4 / 22.2 dB
trainer validation IoU vs SAM mask	0.836
near-fish band PSNR (fins)	23.7 dB
production status	done
visual note (curation)	brown grouper (same species as w48 fish1

Diagnostics

Held-out frames: real crop vs 4D render (composited over the plate)

Estimated pose: fitted ellipsoid + axes on crops

Frame cleaning: identity / occlusion over time

Frames down-weighted / dropped by the robust trainer

Downloads

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

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