pixal3d_mrp_mlx/pixal3d_mlx/camera.py
m3ultra bf8b1a35d5 Close all four open items: MoGe camera, manifold remesh, winding, UV bake
THE DECIMATION FLOOR WAS MISDIAGNOSED. I attributed it to ~180k boundary edges. It is
non-manifold edges. Measured on the shipped 500k mesh:

  boundary edges     32,370
  NON-MANIFOLD       81,112     <- the actual blocker, 2.5x more

Quadric decimation cannot collapse an edge shared by more than two faces. Upstream's
own fix (fill_holes, via CUDA-only cumesh) targets boundaries and caps at
max_hole_perimeter=3e-2, so it was never going to help: trimesh's equivalent moved
boundaries 32,370 -> 30,990 and the floor only 214k -> 210k. That falsified it.

--manifold: voxelise -> fill -> marching cubes. Removes BOTH classes at once and so
closes three of the four items in one change:

  as shipped   499,984 faces  bnd 32,370  nonmani 81,112  watertight=F  IoU 0.969
  remeshed   1,178,142 faces  bnd      0  nonmani      0  watertight=T  IoU 0.949
  -> 20k        19,998 faces  bnd      0  winding consistent            IoU 0.956

25x smaller, fully manifold, consistent winding, for 1.3% silhouette IoU. Lossy by
design - it gives up the dual grid's open-surface representation - so it is opt-in.

UV BAKE is unblocked by the same change: its cost is driven by face count, not by
remesh. 5.0s at 20k faces against >20min at 214k. No longer offline-only when paired
with manifold.

THE SCALING TRAP, worth knowing: marching_cubes returns vertices in VOXEL INDEX space.
Translating without apply_scale(pitch) leaves the mesh ~292x too large. It still
exports and renders as a plausible object; it silhouettes at IoU 0.08. That is how it
was caught.

MoGe-2 CAMERA is now wired and is the default, matching upstream; --fixed-fov keeps
the old constant. It runs once per image in torch/MPS, ~0.4s after load.

Reporting this one straight: it did NOT improve the samples. On 1_img, fixed 49.1 deg
scored 0.893 and MoGe's 29.7 deg scored 0.883. Two caveats keep it as the default
anyway - the silhouette metric projects with the SAME FOV used to generate, so a
wrong-but-consistent camera can still score well and the metric cannot fully arbitrate
camera correctness; and the bundled samples are synthetic renders, not the photographs
MoGe reads. Real photos are the intended input here, and upstream estimates too. But
the constant is one flag away and the measurement is on record rather than assumed.

Operator gains manifold, divisions, fixed_fov. README and PROFILE.md corrected where
they repeated the boundary-edge claim.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-08-03 20:39:45 +10:00

71 lines
2.5 KiB
Python

"""Per-image camera estimation with MoGe-2.
Everything downstream assumes the object exactly fills the frame at a known FOV:
`distance_from_fov` places the camera so a unit mesh spans the image, and the proj
grid back-projects through that camera. A fixed default FOV therefore does not just
change framing — it reconstructs the subject at the WRONG DEPTH SCALE, and the failure
is quiet: you get a clean, plausible mesh that is subtly the wrong shape.
Upstream estimates FOV per image with MoGe-2 and only falls back to a constant when
`--fov` is passed explicitly. This does the same. MoGe runs once per image in torch on
MPS, like DINOv3 and NAF — outside any denoising loop, so parity beats a port.
"""
from __future__ import annotations
import math
import numpy as np
MODEL_NAME = "Ruicheng/moge-2-vitl"
_model = None
def load_moge(device: str = "mps"):
"""Load MoGe-2 once per process."""
global _model
if _model is None:
import torch
from moge.model.v2 import MoGeModel
_model = MoGeModel.from_pretrained(MODEL_NAME).eval().to(device)
_model.requires_grad_(False)
elif str(next(_model.parameters()).device).split(":")[0] != device:
_model = _model.to(device)
return _model
def estimate_fov(image_path: str, device: str = "mps") -> float:
"""Horizontal FOV in radians, from MoGe-2's predicted intrinsics.
`intrinsics[0,0]` is fx NORMALISED by image width, so it must be multiplied back
up before the arctan — the normalisation is easy to miss and yields a plausible
but wrong angle if skipped.
"""
import torch
from PIL import Image
img = Image.open(image_path).convert("RGB")
width, _ = img.size
arr = np.asarray(img, dtype=np.float32) / 255.0
tensor = torch.from_numpy(arr).permute(2, 0, 1).to(device)
model = load_moge(device)
with torch.no_grad():
out = model.infer(tensor)
fx_norm = float(np.asarray(out["intrinsics"].squeeze().cpu())[0, 0])
return 2.0 * math.atan(width / (2.0 * fx_norm * width))
def camera_for(image_path: str, fov: float | None = None, mesh_scale: float = 1.0,
image_resolution: int = 512, device: str = "mps") -> dict:
"""(camera_angle_x, distance) for an image. Estimates FOV when `fov` is None."""
from .proj import distance_from_fov
estimated = fov is None
if estimated:
fov = estimate_fov(image_path, device)
return {"camera_angle_x": float(fov),
"distance": distance_from_fov(fov, mesh_scale, image_resolution),
"estimated": estimated}