Software reuse file

Software reuse file#

ECSS-E-ST-40C Rev.1 / ECSS-Q-ST-80C. This SRF records reused software and reused data, and states the originality of the reverse-chain Synthetic L0 reconstruction tool: it runs a Sentinel-2B L1B backwards through the exact inverse of the operational Synthetic L0->L1B radiometric chain to reconstruct L1A -> L0plus -> Synthetic L0, validated against the reference ESA L0 img.

Introduction#

The deliverable reuses only general-purpose, permissively-licensed libraries and public ESA/Copernicus calibration data. No mission-processor source code is reused or vendored. All algorithms are original implementations from public specifications.

Reused software#

Component

Role

License

numpy

numerical arrays, the entire processing core

BSD-3-Clause

zarr

EOPF L1A/L1B read + Synthetic L0 RAW write (optional read extra)

MIT

Python stdlib json + xml.etree.ElementTree

GIPP JSON parser (+ XML fixtures for tests)

PSF

pytest

test runner (dev only)

MIT

No EOPF CPM, no geometry library, and no credentialed package is required for the referenceized path.

Reused data#

All reused data is public ESA/Copernicus reference data; only the data values are used (no code):

Data

Use

Source / provenance

Spectral Response Functions

per-unit centre/bandwidth/equivalent wavelength

SRF doc COPE-GSEG-EOPG-TN-15-0007 v4.0

Operational GIPP

per-pixel dark + relative response, defects, offsets

R2EQOG / R2DEPI / BLINDP / R2PARA / R2CRCO (read as data)

Sentinel-2 L1 ATBD

forward radiometric model \(X = A\cdot G\cdot L + D\) (the algorithm we invert)

S2-PDGS-MPC-ATBD-L1 §4.1.1 (public specification)

Originality statement#

The reverse-chain inverse radiometric chain (invert offset, relative-response/PRNU, dark, un-bin, SWIR re-stage, defective, crosstalk, on-board-eq; MTF-deconvolution OFF), the GIPP reader, the calibration sub-set and the L1A/L0plus/Synthetic L0 product assembly are original implementations written from the public Sentinel-2 L1 ATBD and the GIPP data layout. No external mission-processor source code is copied, vendored, imported or referenced by name in this deliverable. This satisfies REQ-QUAL-003 (originality), verified by inspection (source review + name grep) in the V&V report. The reverse chain’s own V&V uses only this project’s code: the L0plus codec round-trip (decode(L0plus)==L1A, bit-exact) and validation of the Synthetic L0 against the reference ESA L0 img (10/20 m bands <=~4 DN).