SEI Field Spectroradiometer Accessories

Overview

SEI Field Spectroradiometer Accessories are engineered to extend the measurement flexibility, optical coupling efficiency, and field-deployable robustness of SEI’s portable field spectroradiometers. Designed for rigorous spectral characterization of natural and artificial surfaces—such as vegetation canopies, soils, water bodies, mineral outcrops, and man-made materials—these accessories enable precise radiometric and reflectance measurements across the UV–Vis–NIR range (typically 350–2500 nm, depending on spectrometer configuration). Each component adheres to strict optical alignment tolerances and calibrated throughput specifications, ensuring traceable, repeatable data acquisition under variable ambient conditions. The accessories integrate seamlessly with SEI’s core spectroradiometer platforms—including the PSR+, SR-3500, and SR-6500 series—supporting both laboratory-based calibration workflows and in-situ geospatial surveys compliant with NASA’s AVIRIS-NG preflight protocols and ESA’s FLEX mission validation standards.

Key Features

• Optically matched fiber optic cables: Available in standard lengths (1 m, 2 m, 5 m, 10 m) with SMA 905 connectors and solarization-resistant fused silica cores; numerical aperture (NA) optimized for minimal étendue loss and high signal-to-noise ratio (SNR) at low-light irradiance levels.
• Narrow-field-of-view (FOV) lenses: Interchangeable collimating optics with FOVs of 1°, 3°, 5°, and 8°, enabling targeted spectral sampling of discrete targets (e.g., individual leaves, rock samples, or pavement sections) while minimizing adjacency effects.
• Cosine-corrected irradiance receivers: Calibrated silicon photodiode-based sensors with angular response conforming to ISO/CIE 19476:2014 for hemispherical irradiance measurement; integrated thermal stabilization ensures <±0.5% drift over 0–40°C operating range.
• Integrating spheres: 50 mm and 100 mm diameter PTFE-coated spheres (Labsphere-certified >99% diffuse reflectance) for absolute reflectance and transmittance measurements; compatible with bidirectional reflectance distribution function (BRDF) goniometric setups.
• Contact probes and leaf clamps: Spring-loaded, pressure-controlled contact probes with built-in halogen illumination for dark-adapted leaf spectral analysis; leaf clamps feature adjustable apertures (6 mm, 12 mm, 25 mm) and spectral-grade quartz windows to minimize Fresnel losses.
• Reference calibration panels: Spectrally stable, NIST-traceable Spectralon® panels (99% reflectance, 25 cm × 25 cm) with annual recalibration certificates; optional gray-scale sets (2%, 10%, 50%, 90%) for dynamic range validation and nonlinearity correction.

Sample Compatibility & Compliance

These accessories support a broad spectrum of sample types—including live vegetation (broadleaf and coniferous), soil horizons (A, B, C), aquatic surface films, painted surfaces, and geological specimens—without requiring destructive preparation. All optical components comply with IEC 61000-4-3 (EMC immunity) and MIL-STD-810G for shock/vibration resistance during transport. Fiber assemblies meet RoHS 2011/65/EU and REACH Annex XVII requirements. Reflectance standards are certified per ISO/IEC 17025:2017 by an ILAC-MRA accredited laboratory, and irradiance receivers carry factory calibration reports traceable to NIST SRM 2252 (Spectral Irradiance Scale).

Software & Data Management

SEI accessories operate natively within the proprietary SpectraWiz® software suite (v6.3+), which supports automated accessory recognition, real-time spectral correction (fiber transmission, lens vignetting, cosine error compensation), and batch processing of BRDF, NDVI, PRI, and other vegetation indices. Raw data export is available in ENVI-compatible BIL format, CSV, and HDF5, with embedded metadata fields compliant with ISO 19115-2 for geospatial interoperability. Audit trails, user authentication, and electronic signatures satisfy FDA 21 CFR Part 11 requirements for regulated environmental monitoring applications.

Applications

• Remote sensing ground truthing for satellite and UAV-based hyperspectral missions (e.g., Landsat-9, PRISMA, EnMAP)
• Phenotyping and stress detection in agricultural research (chlorophyll content, water status, nutrient deficiency mapping)
• Mineral identification and lithological mapping in exploration geology
• Urban material classification (roof albedo, pavement aging, solar reflectance index assessment)
• Ecological monitoring of wetland health, snow albedo decay, and coastal sediment composition
• Calibration and validation of laboratory integrating sphere systems and goniospectroradiometers

FAQ

Are all SEI accessories calibrated before shipment?
Yes—each optical component undergoes factory calibration against reference standards, with documented uncertainty budgets and traceability statements included in the delivery package.
Can I mix accessories from different SEI spectroradiometer generations?
Mechanical and optical interfaces are backward-compatible across PSR+, SR-3500, and SR-6500 platforms; however, firmware updates may be required for full spectral correction integration in SpectraWiz®.
Do you provide application-specific accessory bundles?
Yes—custom configurations are available for vegetation phenotyping, soil spectroscopy, and aquatic remote sensing, including pre-validated combinations of probes, lenses, and calibration references.
Is technical support available for field deployment troubleshooting?
SEI offers remote diagnostics, on-site training, and field protocol documentation aligned with CEOS/WGCV Best Practices for In Situ Spectral Measurements.