cuvis-ai-dataloader

Pluggable hyperspectral DataModules for the cuvis-ai ecosystem.

Overview

cuvis-ai-dataloader ships the concrete hyperspectral DataModules for the Cuvis.AI ecosystem. A DataModule is the unit the framework uses for both training and inference: it bundles the data, the labels, the splits, and the train / val / test / predict dataloaders.

This single plugin holds every concrete loader, with per-format heavy deps gated behind optional extras. The cuvis SDK lives only here, behind [cu3s]; no other Cuvis.AI repo pins it.

Key points:

• One plugin, three DataModules, per-format heavy deps behind extras
• The cuvis SDK is isolated here, behind [cu3s]
• Composable split selectors over an attributed sample universe
• cuvis / tifffile / pycocotools import lazily, so the plugin registers with any subset of extras

Splits

Splits are defined in one of two ways:

• Selectors (splits.json) is the general mechanism, shared by every module. Composable selectors over an attributed sample universe are resolved into a committable splits.json by the resolve-splits CLI, then referenced from a DataConfig.splits.
• One universe.csv vocabulary (source, index + optional materialized_path, split, annotation, format, group) is read by both cu3s_multi and npz_multi through a shared parser; each module keeps its own reader. cu3s_multi may carry an inline split column (present → module-owned; absent → needs a splits.json), and resolve-splits --from-csv turns that column into a committable splits.json. npz_multi is selector-only (it rejects a split column) and requires materialized_path (the .npz); for cu3s_multi, materialized_path defaults to source (a raw .cu3s is its own file). source is the posix identity a splits.json selector keys on, so one split resolves against both the raw cu3s data and the converted npz.

Installation

uv pip install "cuvis-ai-dataloader[cu3s,coco]"   # cu3s + COCO
uv pip install "cuvis-ai-dataloader[tiff]"         # TIFF + paired PNG
uv pip install "cuvis-ai-dataloader[all]"          # every format

Extras:

• cu3s: .cu3s session reading via the cuvis SDK binding
• coco: COCO-JSON mask labels (pycocotools, scikit-image)
• tiff: TIFF cube reading (tifffile)
• all: All formats
• dev: Development dependencies

The cu3s extra carries the Windows cuvis-il<3.5.3 pin (the last build with a win_amd64 wheel).

Cuvis SDK (system install, required for cu3s)

The [cu3s] extra installs the cuvis binding (with the Windows cuvis-il<3.5.3 pin noted above), but that binding needs the system-wide C++ Cuvis SDK too, or any .cu3s read fails at runtime. See the Cuvis.AI installation guide for OS support (Windows / Linux; not macOS), the SDK download, and verification. Quick check once installed:

uv run python -c "import cuvis; print(cuvis.__version__)"

Usage

Inference (restore-pipeline) selects a module and its params on the CLI:

restore-pipeline \
  --pipeline-path X.yaml \
  --plugins-dir   <this-repo>/configs/plugins \
  --data-module cu3s \
  --data-arg    cu3s_file_path=X.cu3s \
  --data-arg    annotation_json_path=Y.json

Training (Train / RestoreTrainRun) selects the same module via the yaml DataConfig:

data:
  data_module: cu3s
  splits:
    train:
      - { kind: file_indices, source: X.cu3s, ids: [0, 2, 3] }
    val:
      - { kind: file_indices, source: X.cu3s, ids: [1, 5] }
  batch_size: 4
  params:
    cu3s_file_path: X.cu3s
    annotation_json_path: Y.json
    processing_mode: Reflectance

In-process / notebooks construct the DataModule directly and run it through the Predictor:

from cuvis_ai_dataloader.data import Cu3sDataModule
from cuvis_ai_core.training import Predictor
from cuvis_ai_core.utils.restore import restore_pipeline

pipeline = restore_pipeline("X.yaml", plugins_dirs=[...])
dm = Cu3sDataModule(cu3s_file_path="X.cu3s", batch_size=1)
Predictor(pipeline, dm).predict()

NPZ (npz_multi)

npz_multi loads one frame per compressed .npz, selected by a splits.json over a universe_csv (a universe.csv). It needs no extras (numpy is a core dep) and no Cuvis SDK. Each .npz carries:

• cube: [H, W, C] float32
• wavelengths: [C] (cast to int32)
• mask (optional): [H, W] int32 ground truth (zeros are emitted when absent)
• class_mask (optional): [H, W] uint8 per-pixel COCO category id (0 = background)

The universe_csv requires source, index plus materialized_path (the .npz, required for npz; optional annotation, format, group; extra columns are ignored); materialized_path is relative to the CSV and must not escape it via ... A split column is rejected here (npz is selector-only). Each sample is {cube, mask, class_mask, wavelengths, mesu_index, frame_id}. Unlike the cu3s modules, npz_multi honors pin_memory / persistent_workers / worker_multiprocessing_context (pure-CPU numpy loads benefit from them).

from cuvis_ai_dataloader.data import MultiNpzDataModule
from cuvis_ai_schemas.training.data import DataSplitConfig, Selector, SelectorKind

splits = DataSplitConfig(
    train=[Selector(kind=SelectorKind.FILE_INDICES, source="X.cu3s", ids=[0, 2, 3])],
    val=[Selector(kind=SelectorKind.FILE_INDICES, source="X.cu3s", ids=[1, 5])],
)
dm = MultiNpzDataModule(splits=splits, universe_csv="universe.csv", batch_size=4, num_workers=4)
dm.setup("fit")
batch = next(iter(dm.train_dataloader()))  # cube [B,H,W,C], mask [B,H,W], ...

In a DataConfig (training / restore-trainrun):

data:
  data_module: npz_multi
  batch_size: 4
  splits:
    train:
      - { kind: file_indices, source: X.cu3s, ids: [0, 2, 3] }
    val:
      - { kind: file_indices, source: X.cu3s, ids: [1, 5] }
  params:
    universe_csv: universe.csv

GUI-authored splits over a cu3s folder (contract)

External split authors (e.g. the CuvisNEXT split designer) write a frozen splits.json (a serialized DataSplitConfig with file_indices selectors) against a folder of cu3s files with per-measurement granularity. That contract is cu3s folder mode with frames: measurements:

data:
  data_module: cu3s
  batch_size: 1
  num_workers: 0
  splits:
    splits_path: <absolute path to the frozen splits.json>
  params:
    data_dir: <folder holding the .cu3s files>
    frames: measurements
    recursive: true          # walk per-day subfolders
    processing_mode: Reflectance

The frozen rules both sides implement:

• Universe = every *.cu3s under data_dir (recursive when recursive: true), one sample per measurement 0..N-1, ordered by (source, index).
• Source identity is canonical: the absolute path with forward slashes and filesystem-true case — Python Path(p).resolve().as_posix(), C++/Qt QFileInfo::canonicalFilePath(). Selectors in the authored splits.json must carry exactly this form; matching is string equality, so a moved or renamed member file fails loud with "matched 0 samples" rather than silently shrinking a split.
• uid = <source>#<index> (the sibling COCO image id equals the read position, so it never extends the uid). universe_hash = sha256 over the ordered uids, each followed by \n (cuvis_ai_core.data.splits_io.universe_hash). For file_indices splits the server treats the hash as informational (only positional dir_indices splits are hash-verified); staleness detection is the author's concern.
• Annotations are the sibling <stem>.json COCO next to each cu3s (attached automatically); an empty predict stage means the whole universe.
• Training stages require splits. cu3s does not own split semantics: fit / validate / test with no DataConfig.splits raise instead of silently iterating the whole universe (which would contaminate statistical initialization with anomalous frames). Split-less predict over the whole universe stays valid.

The golden fixture tests/cuvis_ai_dataloader/fixtures/gui_authored_splits.json is the byte-level reference of the authored shape (the {DATA_DIR} token stands in for the machine-specific folder); the same file is committed in the CuvisNEXT test suite and its universe_hash doubles as the shared sha256 test vector. Changing it is a cross-repo contract change.

Architecture

Concrete DataModules subclass cuvis_ai_core.data.datamodule.BaseCuvisAIDataModule and implement validate_params plus the selector hooks enumerate(required_attrs) (the module's attributed sample universe) and build_dataset_from_refs(refs); a module that owns its own splits also implements build_stage_dataset(stage). Per-format cube readers and labelers are internal helpers (data/readers/, data/labelers/), reused but not a plugin contract. Module-top imports stay free of heavy deps; cuvis / tifffile / pycocotools / scikit-image load lazily on first use (data/_extras.py).

Development

uv sync --extra dev
uv run pytest tests/ -v
uv run ruff check cuvis_ai_dataloader/ tests/
uv run ruff format cuvis_ai_dataloader/ tests/
uv run mypy cuvis_ai_dataloader/

Git hooks

Enable the repo's hooks once per clone:

git config core.hooksPath .githooks

• pre-commit: ruff format + ruff check --fix on staged Python, then re-stages.
• pre-push: ruff format --check, ruff check, docstring coverage (uvx interrogate, ≥95%, configured in [tool.interrogate]), and pytest -m "not slow and not gpu".

Skip a hook for one command with --no-verify.

Contributing

Contributions are welcome. Please:

1. Ensure tests pass
2. Run ruff format and ruff check
3. Keep type hints and update docs as needed

License

Licensed under the Apache License 2.0. See LICENSE for details.