Submitted to: Proceedings of SPIE
Publication Type: Abstract Only
Publication Acceptance Date: March 29, 2010
Publication Date: August 1, 2010
Citation: Hunt, E.R., Long, D.S., Eitel, J.U., Daughtry, C.S. 2010. Remote of leaf chlorophyll content at multiple scales using red, green and blue sensing bands [abstract]. Proceedings of SPIE Optics and Photonics. 2010 CDROM. Technical Abstract: Leaf chlorophyll content is an important variable for agricultural remote sensing because of its close relationship to leaf nitrogen content. We propose a triangular greenness index (TGI), which calculates the area of a triangle with three points: ('r, Rr), ('g, Rg), and ('b, Rb), where ' is the center wavelength and R is the reflectance of the red (r), green (g), and blue (b) wavebands. Based on determinants, one formula is TGI = –0.5[('r – 'b)(Rr – Rg) – ('r – 'g)(Rr – Rb)]; other formulae can be derived using a different order of points. TGI was correlated with chlorophyll content using a variety of leaf and plot reflectance data. However, indices using the chlorophyll red-edge (710-730 nm) generally had higher correlations. With broad bands of multispectral sensors and digital cameras, TGI had higher correlations than other indices at leaf and canopy scales. Simulations using a canopy reflectance model indicate an interaction among TGI, leaf area index (LAI) and soil type at low crop LAI, whereas at high crop LAI, TGI was only affected by leaf chlorophyll content. Excess nitrogen fertilizer causes numerous environmental problems, nitrogen management using remote sensing will help balance fertilizer applications with crop nitrogen requirements.