Spectral Evolution / PSR SED

Status: Supported (scoped) · Vendor: Spectral Evolution · Extensions: .sed

.sed is the ASCII export written by Spectral Evolution field spectrometers (PSR and SR series) for reflectance and raw-DN measurements across the VNIR/SWIR range. The file is a key/value header followed by a Data: table whose first column is wavelength. nirs4all-formats parses the table, types each signal column and promotes the field-acquisition header into canonical metadata.

Instruments & software

Produced by Spectral Evolution’s DARWin software for PSR-1100/2500/3500 and SR-1900/3500/6500 handheld spectrometers. The committed corpus is drawn from the PSR-3500 family; SR-series firmware variants remain under-sampled.

File structure

  • A key/value header (e.g. Version:, Instrument:, Measurement:, Channels:, Wavelength Range:, GPS and detector lines), then a literal Data: line.

  • The line after Data: is the column header; the first column is Wvl and the remaining columns are value channels (DN reference/target, Reflect. % or Reflect. [1.0]).

  • The numeric block follows, one wavelength per row.

What nirs4all-formats extracts

  • Signals — one signal per value column after Wvl. Reflectance columns are typed reflectance; DN / reference / target columns are typed raw_counts.

  • Axis — a wavelength axis in nm.

  • Units — inferred from column labels: DN for normalized DN columns, % for Reflect. %, and 1 for Reflect. [1.0].

  • Metadata — the raw header under metadata.vendor, plus promoted canonical fields: instrument/model/serial, measurement mode, radiometric calibration, declared point count, wavelength range, source signal labels/units, detector channels, reference/target detector temperatures and integration times, battery voltages, scan averages, dark mode, foreoptic and its signal units, GPS latitude/longitude/altitude, GPS time, satellite counts and acquisition start/end date and time.

  • Warnings & quality flags — sed_missing_reflectance_signal (plus a missing_reflectance_signal quality flag) when only DN channels are present; sed_point_count_mismatch and sed_column_count_mismatch when declared counts disagree with the parsed table.

Variants & support status

Variant

Status

Notes

PSR+3500 DN + reflectance export

Supported

Raw DN reference/target plus reflectance, 2151-point axis.

PSR-3500 reflectance acquisition

Supported

Firmware/header drift, GPS/date/time and colon-style foreoptic parsing.

DN-only export (no reflectance)

Supported

Read as raw channels; flagged, not promoted to reflectance.

SR-3500 / SR-6500 firmware

Partial

Firmware-specific headers under-covered; more samples wanted.

Limitations & known gaps

  • The reader does not reconstruct reflectance from DN-only acquisitions; the sed_missing_reflectance_signal warning is left for downstream handling.

  • Signal-unit inference is limited to the column labels observed in committed fixtures.

  • SR-series firmware headers and explicit calibrated radiance/irradiance units still need redistributable samples.

Reference readers

Compared full-array against spectrolab (R subprocess) in tests/conformance/; specdal is an additional reference candidate.

Samples & validation

Three fixtures under samples/spectral_evolution/ are golden-backed in crates/nirs4all-formats/tests/goldens/: 1566060_09506_working.sed (PSR+3500 DN + reflectance), 1566060_15025_not_working.sed (broken-but-valid DN-only export carrying the missing_reflectance_signal flag) and serbinsh_cvars_grape_leaf.sed (PSR-3500 grape-leaf acquisition with canonical GPS/date/time metadata). The conformance suite (pytest -m conformance) compares the reflectance signal against spectrolab with a 1e-6 relative tolerance on axis and values. The probe reports format spectral-evolution-sed at Confidence::Definite.