“…Ground-based acquisition of spectral images may partly resolve the problem since it should simultaneously collect the spatial distribution of the widespread target. For relatively simple and cost-effective ground observations, a high spatial-and spectral-resolution imaging system using line sensors has been developed for intensive surveys (Kosaka et al, 2007), but it requires a crane for scanning above the targeted object. On the other hand, handy video cameras or digital cameras have been used for assessing crop leaf nitrogen and/or chlorophyll content (Nakatani and Kawashima, 1994;Kawashima and Nakatani, 1998;Matsuda et al, 2003;Jia et al, 2004;Ku et al, 2004;Casadesus et al, 2007;Takemine et al, 2007) and for analyzing plant cover or phenology of vegetation (Purcell, 2000;Zhou and Robson, 2001;Richardson et al, 2007;Ishihara et al, 2008).…”