SPAD value estimation of paddy leaves using a hyperspectral sensor mounted on a radio-controlled helicopter

Abstract

Stable supply of high quality crop is an urgent requirement for rice cropping facilities in Japan. To cope with this demand, it is absolutely essential to evaluate rice leaf's chlorophyll content by measuring the SPAD values. But it requires lots of elaboration to measure the SPAD values for wide area in paddy. Therefore, the objective of this study is to resolve this problem by estimating the rice leaves SPAD values through remote sensing. Specifically, we made use of a trial observation equipment using hyperspectral sensor mounted on a radio-controlled helicopter, and calculated new indices LVI_pure and LVI_mixture using the obtained data to estimate SPAD values. As a result, the relations between the SPAD value and the estimation index exhibits high correlation : R²=0.885 for LVI_pure and R²=0.927 for LVI_mixture, which facilitated to obtain “the estimated SPAD value image” from the obtained data.