Detectors used in imaging systems always generate optical reflections as the light is never completely absorbed. To estimate or measure the detector optical reflections permits to better manage the induced parasitic photonic signals (ghost and scattering) in imaging devices. We describe different methods to assess these detector reflections. Among them, a powerful test based on etalon effect in Focal Plan Array is detailed for measuring the reflection at different wavelengths even near the cut-off of the detector sensitivity. The physical effects in PV junctions that can explain the observed optical reflections are discussed.
The FLEX mission is defined to perform quantitative measurements of the solar induced vegetation fluorescence to monitor photosynthetic activity. The FLORIS payload is based on a spaceborne 3-channel grating spectrometer operating in the VNIR range.
The retrieval of the faint fluorescence signal from the acquired vegetation spectra is particularly sensitive to straylight.
As results, the straylight requirements on the FLORIS instrument are especially stringent.
For FLORIS a two-step straylight reduction process has been put in place by the Leonardo-Thales Alenia Space team to achieve this requirement. Careful instrument design and manufacturing are followed by digital processing of the raw instrument data.
In this paper we present the feasibility demonstration of the straylight digital correction process, based on simulation of the dedicated data processing and quantitative assessment of the residuals.