COMPOSITING METHODS FOR PROBA-V AND SENTINEL-3: CRITICAL ASSESSMENT OF CURRENT APPROACHES AND POTENTIAL EVOLUTIONS

摘要

A comparison of different compositing methodsrnfor Proba-V surface reflectance products isrnpresented in this paper. The goal is to test thernperformances of the current approach and torninvestigate on potential evolutions, in particularrnin the frame of Sentinel-3 SYN-VGT productsrnbaseline definition. Methods based on the MaxrnNDVI [1], which represent the current baseline,rnare compared to statistical methods, which makernbest use of the information coming from allrnclouds free pixels acquired during therncompositing period, as the Mean Compositingrnmethod [2]. Performances indicators for therndifferent approaches are analysed, in particularrnthe image texture and quality, the spatial noise,rnthe observation geometry distribution as well asrnthe presence of artefacts in the image. As alreadyrnobserved in the literature and confirmed withinrnthis analysis, the Max NDVI approaches havernclear limitations due to the presence ofrndirectional effects in the images, whilernstatistically based methods seem to be the bestrnalternative for implementation in Sentinel-3rnSYN-VGT processing.