Plant treatment based on a water invariant chlorophyll index

Abstract

A method and system of treating plants is provided. The method includes measuring optical properties of a plant using a plurality of spectral bands. The method further includes calculating in a computational device at least two vegetative indexes using the optical properties, each of the at least two vegetative indexes correlating to one or more plant growth parameters. The method further includes calculating in the computational device a water invariant chlorophyll index from at least two vegetative indexes using the plurality of spectral bands. The also provides for treating one or more of the plants based on the water invariant chlorophyll index.

What is claimed is: 
     
         1 . A method for measuring a plant's reflectance, comprising the steps of:
 (a) modulating a light source comprised of one or more LEDS that emit light in the spectral range of 350 nm to 480 nm having a phosphorescent coating, and   (b) detecting light originating from the light source reflected off of the plant in the presence of ambient light in one or more spectrally sensitive photodetectors.   
     
     
         2 . The method of  claim 1 , wherein the phosphor coating comprises one or more rare earth elements selected from the group consisting of cerium, yttrium, terbium, gadolinium, and europium. 
     
     
         3 . The method of  claim 1  further comprising monitoring and stabilizing intensity of the light source. 
     
     
         4 . The method of  claim 1  further comprising calculating a vegetation index using detected light. 
     
     
         5 . The method of  claim 2  further comprising performing spectral selectivity using a narrowband optical filter. 
     
     
         6 . The method of  claim 5  wherein the narrowband optical filter is configurable. 
     
     
         7 . The method of  claim 5  further comprising reducing specular reflections using polarizing filters. 
     
     
         8 . The method of  claim 1  further comprising performing spectral selectivity using a linear variable filter. 
     
     
         9 . The method of  claim 1  further comprising performing spectral selectivity using a diffraction grating. 
     
     
         10 . The method of  claim 1  wherein the ambient light is sunlight. 
     
     
         11 . The method of  claim 1  wherein the phosphor re-emits light from an LED light source. 
     
     
         12 . The method of  claim 1  wherein the phosphor emits low color temperature white light. 
     
     
         13 . The method of  claim 1  wherein the phosophor emits green, yellow, orange, or red light. 
     
     
         14 . The method of  claim 1  further comprising mounting the light sensor on a moving vehicle.