ID:
publications-2128
Type:
Peer reviewed articles
Year:
2020
Authors:
Olivier Burggraaff
Title:
Biases from incorrect reflectance convolution
Venue/Journal:
Optics Express
DOI:
10.1364/oe.391470
Research type:
Digital twin
Water System:
Irrigation Systems
Technical Focus:
Abstract:
Reflectance, a crucial earth observation variable, is converted from hyperspectral to multispectral through convolution. This is done to combine time series, validate instruments, and apply retrieval algorithms. However, convolution is often done incorrectly, with reflectance itself convolved rather than the underlying (ir)radiances. Here, the resulting error is quantified for simulated and real multispectral instruments, using 18 radiometric data sets (Nā=ā1799 spectra). Biases up to 5% are found, the exact value depending on the spectrum and band response. This significantly affects extended time series and instrument validation, and is similar in magnitude to errors seen in previous validation studies. Post-hoc correction is impossible, but correctly convolving (ir)radiances prevents this error entirely. This requires publication of original data alongside reflectance.
Link with Projects:
776480
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