Ray tracing based simulation of stray light effect for geostationary ocean color imager

Correction of Stray-Light-Driven Interslot Radiometric Discrepancy (ISRD) Present in Radiometric Products of Geostationary Ocean Color Imager (GOCI)

“…One of the strongest artificial sources of the ISRD is the stray light generated inside the sensor instrument [11], [14]. A simulation experiment performed by the Monte Carlo raytracing technique (interactive ray tracing) revealed that the paths of the incoming light entering the sensor instrument may not be fully controlled inside the instrument, as supposed in the original sensor design.…”

“…A simulation experiment performed by the Monte Carlo raytracing technique (interactive ray tracing) revealed that the paths of the incoming light entering the sensor instrument may not be fully controlled inside the instrument, as supposed in the original sensor design. As a result, stray light occurs by undesirable reflections from sensor elements, such as the filters, the support beam, and the thermal heater [11]. The stray light induces radiometric inflation to each slot, in which the intensity of the inflation is largest in the bottom of each slot and decreases as it proceeds northward.…”

“…Slot k 2 is selected as the slot that is less affected by the SLRI, which is the bottom slot in the case of the horizontal overlaps because the SLRI is negligible in the upper part of the slots [11]. Table II shows R ISRD for the vertical and horizontal overlaps for all the eight bands.…”

“…2 shows how the ISRD deteriorates the continuity in the marginal parts of the slots in the L1B product, which is demonstrated by the band difference and band ratio images between Bands 6 and 7. One of the factors that cause the ISRD is currently believed to be the stray light generated from the misalignment of sensor elements, such as filters, the support beam, and the thermal heater, the intensity of which is strengthened by bright targets in distant areas possibly located outside the slot [10], [11]. In this paper, the radiometric surge caused by the stray light is referred to as the stray-light-driven radiometric inflation (SLRI).…”

“…Only relative and partial quantification is possible in the slot boundary regions where the adjacent slots overlap, and multiple values are available for the same location for comparison. However, the spatial extent of the SLRI often goes beyond the overlapped region, and the quantification in the interior of individual slots is still difficult without independent references [11].…”