Processing of FORMOSAT-2 daily revisit imagery for site surveillance

The successful operation of FORMOSAT-2, which was launched on May 21, 2004, proved the concept that the temporal resolution of a remote sensing system can be much improved by deploying a high spatial resolution sensor in a daily revisit orbit, and each accessible scene can be systematically observed from the same angle under similar illumination conditions. These characteristics make FORMOSAT-2 an ideal satellite for site surveillance. The unique orbit and the arrangement of the charge-coupled device lines onboard FORMOSAT-2, however, also raise new challenges in image processing. This paper describes a fast and automatic system that is able to process a large amount of FORMOSAT-2 daily revisit imagery for the purpose of site surveillance. The system is comprised of several modules, including level-2 product generation, hand-to-hand coregistration, a spectral preserved pan-sharpening technique, and multitemporal imagery matching. Two examples processed by the system are given to demonstrate the applicability of FORMOSAT-2 daily revisit imagery for site surveillance. The experiences of operating FORMOSAT-2 for more than one and a half years are summarized, and the advantages and disadvantages of a daily revisit orbit are discussed. Experience obtained from this paper would benefit the system design and image processing of future satellite missions with similar specifications, such as the Pleiades HR scheduled to be launched in 2008.