AlphaSpectra BridgeCheck

See beyond your VNIR sensor—without pretending a prediction is a measurement.

BridgeCheck is a commercially usable, open-source tool for leaf spectroscopy. It generates a physics-grounded, explicitly model_derived SWIR candidate from measured VNIR reflectance and can audit the unchanged decoder on paired customer measurements before anyone trusts it.

Try the public, browser-only app: https://harrrshall.github.io/alphaspectra-bridgecheck/

What it does

• predict: measured 400–1000 nm leaf reflectance → candidate 1052–2400 nm reflectance.
• audit: paired same-sample VNIR+SWIR → grouped comparison against two baselines, spectral-distance bins, bootstrap intervals, context controls and strict no-clipping checks.
• Runs locally on CPU or entirely in a browser. The static app uploads nothing.
• Five one-click browser examples cover a measured training-domain spectrum, lower/median/higher generated reference geometry and a deliberate support-tail warning. Their provenance is displayed in the interface; generated cases are not measurements or accuracy evidence.

What it does not do

BridgeCheck does not measure SWIR, diagnose disease, identify pathogens, infer drought or health, replace a calibrated sensor, or provide calibrated uncertainty. Generated bands must never be silently concatenated with measurements. A dataset-specific reconstruction pass still requires a separate downstream measurement-value study.

Companion tool: BandTrace

BandTrace is a separate local Linux CLI for checking whether a declared sensor-to-model spectral route agrees with an executable- reported tap, whether required bands affect one selected numeric output on adequate probes, and whether routed sensor response functions remain within supplier-declared training support. It reports executable (X), spectral-support (S) and biological-transport (T) states separately.

The verified reference release reaches X3 + S3 + T0; T0 means biological transport was not evaluated. That reference result is not evidence that a customer model/camera pair will pass. BandTrace does not run in the BridgeCheck browser app, BridgeCheck sends it no inputs, and neither product validates the other. See the product and licensing matrix and the independent BandTrace source and release record.

Quick start

python -m pip install .
bridgecheck predict examples/vnir_example.csv --output prediction.csv --report report.json
bridgecheck info

Run the local API and browser UI:

python -m pip install ".[api]"
bridgecheck serve --host 127.0.0.1 --port 8080

Then open http://127.0.0.1:8080 or call:

curl -X POST http://127.0.0.1:8080/v1/predict \
  -H 'content-type: application/json' \
  --data @examples/predict_request.json

Container:

docker build -t alphaspectra-bridgecheck:0.1.0 .
docker run --rm -p 8080:8080 alphaspectra-bridgecheck:0.1.0

Input contract

CSV prediction input has two columns:

wavelength_nm,reflectance
400,0.052
404,0.053
...
1000,0.441

Reflectance must be an absolute decimal fraction, finite, ordered and unclipped. Supported V1 input has at least 100 bands, starts by 420 nm, reaches 980 nm and has no gap larger than 10 nm. Radiance, absorbance, SNV, percentages and normalized features are rejected.

Audit input is long-form CSV with columns sample_id, group_id, band_origin, wavelength_nm, reflectance; band_origin is either measured_context or measured_target.

Evidence

The frozen decoder reduced held-SWIR MAE by 61.98% on CABO and 55.28% on a separate NASA FFT source. On 230 proximal HySpex cubes it still reduced aggregate MAE by 49.83%, but failed the strict camera/radiometric gate and neither reconstructed nor actual measured SWIR improved held-plant drought prediction. BridgeCheck exposes that boundary instead of hiding it. See MODEL_CARD.md and the machine-readable RELEASE_VERIFICATION.json.

Licensing

Code is Apache-2.0. The transformed candidate bank carries the source-data attribution and terms in DATA_ATTRIBUTION.md. EcoSIS labels the source generic cc-by without a version; this is disclosed rather than silently upgraded to CC-BY-4.0. Commercial use is permitted subject to those attribution terms. See THIRD_PARTY_NOTICES.md.

Privacy and security

The hosted static browser app processes spectra locally and has no upload backend. The optional API is self-hosted. See PRIVACY.md and SECURITY.md.