Construction method of spectral index for monitoring red spot disease of broad beans

The invention provides a construction method of spectral indexes for monitoring the red spot disease of broad beans, which comprises the following steps: firstly, acquiring spectral curves of different degrees of infection of the red spot disease of the broad beans based on spectral reflectivity, and acquiring sensitive wavebands of the red spot disease of the broad beans and red spot disease sensitive indexes of each spectral band; then, on the basis of a PROSAIL model, in combination with the red spot disease sensitivity index of each spectrum band, obtaining a canopy insensitive wave band; and finally, constructing the red spot disease index LSDI. According to broad bean red spot disease spectral characteristics and healthy vegetation canopy reflection characteristics, a spectral index which is sensitive to broad bean red spot disease and insensitive to canopy structures is constructed, and the purposes of enhancing disease information and inhibiting canopy structure difference information are achieved, so