The normalized difference red edge index (NDRE) is a metric that can be used to analyse whether images obtained from multi-spectral image sensors contain healthy vegetation or not.Barnes, E. M., Clarke, T. R., Richards, S. E., Colaizzi, P. D., Haberland, J., Kostrzewski, M., ... & Lascano, R. J. (2000, July). Coincident detection of crop water stress, nitrogen status and canopy density using ground based multispectral data. In Proceedings of the Fifth International Conference on Precision Agriculture, Bloomington, MN, USA (Vol. 1619). It does this by measuring the amount of chlorophyll in a plant.
It is similar to Normalized Difference Vegetation Index (NDVI) but uses the ratio of Near-Infrared and the edge of Red as follows:
The red edge is the part of the spectrum centered around 715 nm.
The Index will give a value between -1.0 to +1.0, with a higher value showing a healthy plant environment.
See also Normalized difference water index
References
External links
IEE Explore website, Normalized Difference Red-Edge Estimation With Modified DiscoGAN Model, article by Hyeon-Beom Choi, Kwon-Hee Han and Jeongwook Seo (2006) Spectral Reflectance Changes Associated with Autumn Senescence of Aesculus hippocastanum L. and Acer platanoides L. Leaves. Spectral Features and Relation to Chlorophyll Estimation
Chlorophyll Absorption Barnes, T.R., Clarke, S.E. Richards et al. 2000. Coincident Detection of Crop Water Stress, Nitrogen Status and Canopy Density using Ground-Based Multispectral Data. Proceedings of the Fifth International Conference on Precision Agriculture