The Level-1C processing uses the Level-1B product and applies radiometric and geometric corrections (including orthorectification and spatial registration) to generate the Level-1C (TOA reflectance) product.

Figure 1: Level-1C Processing Overview

• Level-1C Tiles Association. This module selects predefined tiles which intersect the image footprint.
• Level-1C Resampling Grid Computation. This step calculates the resampling grids, linking the image in native geometry to the target geometry (orthoimage).
• Resampling on Level-1C Geometry. This processing step resamples each spectral band in the geometry of the orthoimage using the resampling grids and an interpolation filter. In addition, it calculates the TOA reflectance.
• Masks Computation. This step generates the cloud, cirrus and snow/ice masks at Level-1C geometry.
• Level-1C Compression. This processing step compresses Level-1C imagery using the JPEG2000 algorithm. Level-1C data is generated at the end of this step.