Estimating rice flower intensity using flower spectral information from unmanned aerial vehicle (UAV) hyperspectral images

•Acquiring and analysis of the spectral information of rice flowering.•Innovative flower spectra of rice and different types of indices derived from them.•Good estimation effect of flower intensity using stepwise multiple linear regression and random forest with vegetation indices and flower indices.•Great potential of spectral information of vegetation during the flowering stage in estimating flower intensity and yield.