TY - JOUR ID - buschmann1993 AU - Buschmann, Claus TI - Fernerkundung von Pflanzen - Ausbreitung, Gesundheitszustand und Produktivitfit T2 - Naturwissenschaften PY - 1993 VL - 80 SP - 439-453 ER - TY - JOUR ID - datt1998 AU - Datt, Bisun TI - Remote Sensing of Chlorophyll a, Chlorophyll b, Chlorophyll a+b, and Total Carotenoid Content in Eucalyptus Leaves UR - http://www.sciencedirect.com/science/article/pii/S0034425798000467 DO - 10.1016/s0034-4257(98)00046-7 T2 - Remote Sensing of Environment PY - 1998 SN - 0034-4257 VL - 66 IS - 2 SP - 111-121 AB - Algorithms based on reflectance band ratios have been developed for the remote estimation of chlorophyll a, chlorophyll b, chlorophyll a+b, and total carotenoid content of Eucalyptus leaves. Reflectance spectra over the 400–2500 nm range with a spectral resolution of 2 nm and the content of chlorophylls a, b, a+b, and total carotenoids were determined for leaves from several Eucalyptus species covering a wide range of chlorophyll a content (0.0121–0.0435 mg/cm2). Maximum sensitivity of reflectance to variation in pigment content was found in the green wavelength region at 550 nm and at 708 nm in the far-red wavelengths. The reflectance in the main pigment absorption regions in the blue (400–500 nm) and red (660–690 nm) wavelengths proved to be insensitive to variation in pigment content. The ratio R672/(R550× R708) correlated best with chlorophyll a, chlorophyll a+b, and total carotenoid contents. The ratio R672/R550 correlated best with chlorophyll b content. Reflectance ratios involving near infrared bands such as R750/R550 and R750/R700 did not correlate well with pigment content. This was due to the differential scattering effects of the wide range of young and mature leaf samples. A method was developed for adjusting all spectra to the same level of scatter. The near-infrared-based reflectance ratios from the scatter adjusted spectra showed high sensitivity to pigment content. The ratio R860/(R550×R708) from the scatter adjusted spectra correlated best with chlorophyll a, chlorophyll a+b, and total carotenoid contents, while R860/R550 correlated best with chlorophyll b content. The newly developed algorithms were tested on a validation data set and allowed accurate estimates of leaf pigment content. The pigment contents estimated by the ratios from untransformed spectra, R672/(R550×R708) and R672/R550, were found to be not significantly different from the estimates obtained using the scatter-adjusted reflectance ratios, R860/(R550×R708) and R860/R550. ER - TY - JOUR ID - rondeaux1996 AU - Rondeaux, Geneviève AU - Steven, Michael AU - Baret, Frédéric TI - Optimization of soil-adjusted vegetation indices UR - http://www.sciencedirect.com/science/article/pii/0034425795001867 DO - 10.1016/0034-4257(95)00186-7 T2 - Remote Sensing of Environment PY - 1996 SN - 0034-4257 VL - 55 IS - 2 SP - 95-107 AB - The sensitivity of the normalized difference vegetation index (NDVI) to soil background and atmospheric effects has generated an increasing interest in the development of new indices, such as the soil-adjusted vegetation index (SAVI), transformed soil-adjusted vegetation index (TSAVI), atmospherically resistant vegetation index (AR VI), global environment monitoring index (GEMI), modified soil-adjusted vegetation index (MSAVI), which are less sensitive to these external influences. These indices are theoretically more reliable than NDVI, although they are not yet widely used with satellite data. This article focuses on testing and comparing the sensitivity of NDVI, SAVI, TSAVI, MSAVI and GEMI to soil background effects. Indices are simulated with the SAIL model for a large range of soil reflectances, including sand, clay, and dark peat, with additional variations induced by moisture and roughness. The general formulation of the SAVI family of indices with the form VI = (NIR - R) / (NIR + R + X) is also reexamined. The value of the parameter X is critical in the minimization of soil effects. A value of X = 0.16 is found as the optimized value. Index performances are compared by means of an analysis of variance. ER - TY - JOUR ID - tucker1979 AU - Tucker, C. J. AU - Elgin Jr, J. H. AU - McMurtrey Iii, J. E. AU - Fan, C. J. TI - Monitoring corn and soybean crop development with hand-held radiometer spectral data UR - http://www.sciencedirect.com/science/article/pii/003442577990004X DO - 10.1016/0034-4257(79)90004-x T2 - Remote Sensing of Environment PY - 1979 SN - 0034-4257 VL - 8 IS - 3 SP - 237-248 AB - Red and photographic infrared data were collected with a hand-held radiometer under a variety of conditions at 4- to 12-day intervals throughout the growing season and were used to monitor corn and soybean growth and development. The normalized difference transformation was used to effectively compensate for the variation in irradiational conditions. With these data, plotted against time, green-leaf biomass dynamics were compared between the crops. By this approach, based entirely upon spectral inputs, the crop canopies were nondestructively monitored. Five spectral stages were defined and were related to crop development for corn and soybeans. ER - TY - JOUR ID - xie2007 AU - Xie, H. AU - Tian, Y. Q. AU - Granillo, J. A. AU - Keller, G. R. TI - Suitable remote sensing method and data for mapping and measuring active crop fields UR - ://WOS:000244093200023 DO - 10.1080/01431160600702673 T2 - International Journal of Remote Sensing PY - 2007 DA - Jan SN - 0143-1161 VL - 28 IS - 1-2 SP - 395-411 N1 - ISI Document Delivery No.: 134OR Times Cited: 9 Cited Reference Count: 22 Xie, H. Tian, Y. Q. Granillo, J. A. Keller, G. R. Taylor & francis ltd Abingdon AB - The objective of the study was to examine suitable remote sensing methods and data for mapping and measuring the acreages of active crop lands in order to improve irrigation management. We compared classification results from a supervised classification method and a method using normalized difference vegetation index (NDVI) with additional pre-classification processing. IKONOS and Landsat Enhanced Thematic Mapper Plus (ETM+) images were tested to see if high spatial resolution remote sensing data would have significant advantages in distinguishing between active and fallow lands. The classification achieved an overall accuracy of 93.63%. The results showed that the supervised classification did not have a clear advantage over the simple method using NDVI at the level of distinguishing between active crops and fallow lands. The result suggests that using ETM + instead of IKONOS high spatial resolution imageries is appropriate because of the high cost of IKONOS imageries and image heterogeneity of agricultural fields. It was shown that pre-processing with a mask to exclude the non-agricultural objects blended with agricultural fields is critical. KW - soil heat-flux KW - vegetation indexes KW - net-radiation KW - satellite KW - management KW - imagery ER - TY - ELEC ID - idb AU - Henrich, V. AU - Krauss, G. AU - Götze, C. AU - Sandow, C. TI - The IndexDatabase UR - https://www.indexdatabase.de/ CY - Bonn PY - 2011 DA - 2011 ER -