TY - CPAPER ID - apan2003 AU - Apan, Armando AU - Held, Alex AU - Phinn, Stuart AU - Markley, John TI - Formulation and assessment of narrow-band vegetation indices from EO-1 hyperion imagery for discriminating sugarcane disease UR - http://eprints.usq.edu.au/8061/ PR - Spatial Sciences Institute T2 - 2003 Spatial Sciences Institute Conference: Spatial Knowledge Without Boundaries (SSC2003) CY - Canberra, Australia PY - 2003 SP - 1-13 N1 - No evidence of copyright restrictions. AB - The increasing commercial availability of hyperspectral image data promotes growing interests in the development of application-specific narrow-band spectral vegetation indices (SVIs). However, the selection of the optimum SVIs for a particular purpose is not straightforward, due to the wide choice of band combinations and transformations, combined with specific application purposes and conditions. Thus, the aim of this study was to develop an approach for formulating and assessing narrow-band vegetation indices, particularly those from EO-1 Hyperion imagery. The focus of SVI development was for discriminating sugarcane areas affected by 'orange rust' (Puccinia kuehnii) disease in Mackay, Queensland, Australia. After a series of pre-processing and post-atmospheric correction techniques, an empirical-statistical approach to SVI development was designed and implemented. This included the following components: a) selection of sample pixels of diseased and nondiseased areas, b) visual examination of spectral plots to identify bands of maximum spectral separability, c)generation of SVIs, d) use of multiple discriminant function analysis, and e) result interpretation and validation. From the forty existing and newly developed vegetation indices, the output discriminant function (i.e. a linear combination of three indices) attained a classification accuracy of 96.9% for the hold-out sample pixels. The statistical analyses also produced a list of function coefficients and correlation rankings that indicate the predictive potential of each SVI. The newly formulated 'Disease-Water Stress Indices' (DSWI) produced the highest correlations. The approach designed for this study provided a systematic framework in the formulation and assessment of SVIs for sugarcane disease detection. KW - hyperspectral remote sensing, spectral vegetation indices, sugarcane disease, Hyperion ER - TY - JOUR ID - aparicio2004 AU - Aparicio, N. AU - Villegas, D. AU - Royo, C. AU - Casadesus, J. AU - Araus, J. L. TI - Effect of sensor view angle on the assessment of agronomic traits by ground level hyper-spectral reflectance measurements in durum wheat under contrasting Mediterranean conditions UR - http://dx.doi.org/10.1080/0143116031000116967 DO - 10.1080/0143116031000116967 T2 - International Journal of Remote Sensing PY - 2004 DA - 2004/03/01 SN - 0143-1161 VL - 25 IS - 6 SP - 1131-1152 AB - The objective of this work is to study the effect of changing the sensor view angle on spectral reflectance indices and their relationships with yield and other agronomic traits. Canopy reflectance spectra of 25 durum wheat genotypes were measured with a field spectroradiometer at two view angles, nadir and 30°, from anthesis to maturity in two years and two water regimes. Nine spectral reflectance indices were calculated from reflectance measurements for correlation with yield and several agronomic traits. At off-nadir position more reflected radiation was collected, associated with the reflective characteristics of stems. The performance of the indices predicting the yield and the agronomic traits varied as a function of sensor view angle, and were moreover affected by leaf area index (LAI) value. At high LAI, simple ratio (SR) and normalized difference vegetation index (NDVI), calculated at off-nadir position, were better predictors of traits related to the density of stems and poorer predictors of traits related to green area. On the other hand, at low LAI the indices normalized pigment chlorophyll index (NPCI) and water index (WI) were better predictors of yield and all the other traits when the sensor view angle was at nadir, whereas no differences due to sensor angle were accounted for the other three indices. The different performance of indices at low and high LAI is discussed. ER - TY - JOUR ID - ceccato2002 AU - Ceccato, Pietro AU - Gobron, Nadine AU - Flasse, Stéphane AU - Pinty, Bernard AU - Tarantola, Stefano TI - Designing a spectral index to estimate vegetation water content from remote sensing data: Part 1: Theoretical approach UR - http://www.sciencedirect.com/science/article/pii/S0034425702000378 DO - 10.1016/s0034-4257(02)00037-8 T2 - Remote Sensing of Environment PY - 2002 SN - 0034-4257 VL - 82 IS - 2–3 SP - 188-197 AB - This paper describes the methodology used to create a spectral index to retrieve vegetation water content from remotely sensed data in the solar spectrum domain. A global sensitivity analysis (GSA) using radiative transfer models is used to understand and quantify vegetation water content effects on the signal measured at three levels: leaf, canopy, and atmosphere. An index is then created that optimises retrieval of vegetation water content (in terms of water quantity per unit area at canopy level) and minimises perturbing effects of geophysical and atmospheric effects. The new index, optimised for the new SPOT-VEGETATION sensor, is presented as an example. Limitations and robustness of the index are also discussed. ER - TY - JOUR ID - datt1999 AU - Datt, Bisun TI - Remote Sensing of Water Content in Eucalyptus Leaves DO - http://dx.doi.org/10.1071/BT98042 T2 - Australian Journal of Botany PY - 1999 VL - 47 IS - 6 SP - 909-923 AB - The spectral reflectance of leaves from several Eucalyptus species was measured over the 400–2500 nm wavelengths with a laboratory spectroradiometer. The relationship of reflectance with the gravimetric water content and equivalent water thickness (EWT) of the leaves was analysed. The results showed that EWT was strongly correlated with reflectance in several wavelength regions. No significant correlations could be obtained between reflectance and gravimetric water content. It was also possible to confirm theoretically that reflectance changes of leaves could be directly linked to changes in EWT but not to changes in gravimetric water content. Several existing reflectance indices were evaluated for estimation of leaf water content and some new indices were developed and tested. Two semi-empirical indices developed in this study, (R850 - R2218)/(R850 - R1928) and (R850 - R1788)/(R850 - R1928), were found to show significantly stronger correlations with EWT than all other indices tested. It was also shown that these new indices were least sensitive to the effects of radiation scatter. The indices (R850 - R2218)/(R850 - R1928) and (R850 - R1788)/(R850 - R1928) are therefore proposed as two new indices for the remote estimation of vegetation water content. ER - TY - JOUR ID - penuelas1993 AU - Penuelas, J. AU - Filella, I. AU - Biel, C. AU - Serrano, L. AU - Save, R. TI - The reflectance at the 950–970 nm region as an indicator of plant water status UR - http://dx.doi.org/10.1080/01431169308954010 DO - 10.1080/01431169308954010 PR - Taylor & Francis T2 - International Journal of Remote Sensing PY - 1993 SN - 0143-1161 VL - 14 IS - 10 SP - 1887-1905 AB - We present new remote sensing indices of plant water status: the ratio between the reflectance at 970 nm, one of the water absorption bands, and the reflectance at a reference wavelength, 900 nm (R970/R9000; the first derivative minimum in this near-infrared region (dNIRminimum ) and the wavelength where this minimum is found ( ?NIRminimum). In order to evaluate them, we carried out three experiments. Daily irrigated gerbera plants were allowed to dry until almost wilting and then daily irrigation was restarted; pepper and bean plants were grown for four months submitted to two different irrigation treatments; and bean detached leaves were submitted to progressive dehydration whereas pressure-volume curves were being carried out. In gerbera plants, the trough about 950?970 nm decreased as the drought was increasing. Therefore, the R970/R900 index and the dNIRminimum closely tracked the changes in relative water content (RWC), leaf water potential, stomatal conductance and the foliage-air temperature differences. The ?dNIRminimum tracked even better these changes in gerberas. However, these water status indices began to be significant when the water stress was already well developed, at RWC smaller than 85 per cent. The same happened to detached leaves of beans which did not present differences above ?1·55 MPa water potential. Beans and peppers growing at soil matric potentials larger than ?0·04 MPa presented higher R970/R900 values than those growing at soil matric potentials only larger than ?0·01 MPa. In all the cases, the maximum response of these indices was found in the varieties or the species that lost cell wall elasticity in response to drought stress. This could indicate an important structural component in these indices changes. Relative water content itself seemed to be, however, the most important factor as shown by the highest correlation coefficients with these spectral indices. These spectral signals were more evident at canopy level than at leaf level. They seem to be useful as water status indicators at ground level, especially when there are not important changes of LAI and when plants wholly cover the soil. ER - TY - JOUR ID - penuelas1997 AU - Penuelas, J. AU - Pinol, J. AU - Ogaya, R. AU - Filella, I. TI - Estimation of plant water concentration by the reflectance Water Index WI (R900/R970) UR - http://dx.doi.org/10.1080/014311697217396 DO - 10.1080/014311697217396 T2 - International Journal of Remote Sensing PY - 1997 DA - 1997/09/01 SN - 0143-1161 VL - 18 IS - 13 SP - 2869-2875 AB - Abstract Water Index WI (R900/R970) was used for the estimation of plant water concentration (PWC) by ground-based, reflectance measurements. Reflectance and PWC were measured for adult plants growing in the field throughout an annual cycle and in potted seedlings submitted to progressive desiccation. The species studied were characteristicly Mediterranean: Pinus halepensis, Quercus ilex, Quercus coccifera, Arbutus unedo, Cistus albidus, Cistus monspeliensis, Phillyrea angustifolia, Pistacia lentiscus and Brachypodium retusum . WI was significantly correlated with PWC when all the species were considered together, and with almost all the species considered individually, especially when a wider range of PWC was obtained by extreme dessication of experimental plants. The correlations increased when normalizing WI by NDVI. The wavelength of the trough corresponding to water absorption band tended to shift from 970-980 nm to lower wavelengths 930-950 nm with decreasing PWCs. Infrared measurement of plant temperature and T leaf - T air provided worse assessment of PWC. A simple radiometer measuring plant reflectance at 680, 900, and 970nm could speed up the measurement of PWC, and be useful in wildfire risk evaluation and drought assessment. ER - TY - JOUR ID - pe_uelas1998 AU - Peñuelas, J. AU - Filella, I. TI - Visible and near-infrared reflectance techniques for diagnosing plant physiological status UR - http://dx.doi.org/10.1016/S1360-1385(98)01213-8 DO - 10.1016/S1360-1385(98)01213-8 T2 - Trends in Plant Science PY - 1998 SN - 13601385 VL - 3 IS - 4 SP - 151-156 ER - TY - JOUR ID - pinter2003 AU - Pinter, P. J. AU - Hatfield, J. L. AU - Schepers, J. S. AU - Barnes, E. M. AU - Moran, M. S. AU - Daughtry, C. S. T. AU - Upchurch, D. R. TI - Remote sensing for crop management UR - ://WOS:000221193400006 T2 - Photogrammetric Engineering and Remote Sensing PY - 2003 DA - Jun SN - 0099-1112 VL - 69 IS - 6 SP - 647-664 N1 - ISI Document Delivery No.: 817RA Times Cited: 88 Cited Reference Count: 256 Pinter, PJ Hatfield, JL Schepers, JS Barnes, EM Moran, MS Daughtry, CST Upchurch, DR Amer soc photogrammetry Bethesda AB - Scientists with the Agricultural Research Service (ARS) and various government agencies and private institutions have provided a great deal of fundamental information relating spectral reflectance and thermal emittance properties of soils and crops to their agronomic and biophysical characteristics. This knowledge has facilitated the development and use of various remote sensing methods for non-destructive monitoring of plant growth and development and for the detection of many environmental stresses which limit plant productivity. Coupled with rapid advances in computing and position-locating technologies, remote sensing from ground-, air-, and space-based platforms is now capable of providing detailed spatial and temporal information on plant response to their local environment that is needed for site specific agricultural management approaches. This manuscript, which emphasizes contributions by ARS researchers, reviews the biophysical basis of remote sensing; examines approaches that have been developed, refined, and tested for management of water, nutrients, and pests in agricultural crops; and assesses the role of remote sensing in yield prediction. It concludes with a discussion of challenges facing remote sensing in the future. KW - water-stress index KW - spectral-biophysical data KW - soil heat-flux KW - infrared KW - aerial photography KW - laser-induced fluorescence KW - constant leaf KW - temperature KW - adjusted vegetation index KW - surface-energy balance KW - clover-seed production KW - gossypium-hirsutum l ER - TY - JOUR ID - pu2008 AU - Pu, Ruiliang AU - Gong, Peng AU - Yu, Qian TI - Comparative Analysis of EO-1 ALI and Hyperion, and Landsat ETM+ Data for Mapping Forest Crown Closure and Leaf Area Index UR - http://www.mdpi.com/1424-8220/8/6/3744/ T2 - Sensors PY - 2008 SN - 1424-8220 VL - 8 IS - 6 SP - 3744-3766 ER - TY - JOUR ID - royo2003 AU - Royo, C. AU - Aparicio, N. AU - Villegas, D. AU - Casadesus, J. AU - Monneveux, P. AU - Araus, J. L. TI - Usefulness of spectral reflectance indices as durum wheat yield predictors under contrasting Mediterranean conditions UR - http://dx.doi.org/10.1080/0143116031000150059 DO - 10.1080/0143116031000150059 T2 - International Journal of Remote Sensing PY - 2003 DA - 2003/01/01 SN - 0143-1161 VL - 24 IS - 22 SP - 4403-4419 ER - TY - JOUR ID - strachan2002 AU - Strachan, Ian B. AU - Pattey, Elizabeth AU - Boisvert, Johanne B. TI - Impact of nitrogen and environmental conditions on corn as detected by hyperspectral reflectance DO - 10.1016/s0034-4257(01)00299-1 T2 - Remote Sensing of Environment PY - 2002 SN - 0034-4257 VL - 80 IS - 2 SP - 213-224 AB - Indices derived from hyperspectral reflectance spectra have the potential to be used as indicators of environmental stress in crops. This study uses canopy-scale, ground-based measurements of hyperspectral reflectance to demonstrate the temporal patterns in corn development under imposed fertility (N rate) and environmental (water availability) stresses. In 1998, two large areas in a 30-ha corn (Zea mays, L.) field near Ottawa, Canada (45°18′N, 75°44′W) were supplied with 99 and 17 kg N ha−1, while the balance of the field received the recommended rate of 155 kg N ha−1. Reflectance measurements were taken nine times using a portable spectroradiometer at georeferenced locations within these areas. Individual reflectance-based indices demonstrated the relative differences between application rates and identified both nitrogen and water stresses at various times in the growing season. No single index was able to describe the status of the corn crop throughout the season. Canonical discriminant analysis provided accurate classification of samples by N rate during early, mid, and late season conditions with overall success rates of 70%, 88%, and 93%, respectively. A shift in importance from green-based derivatives to red-based derivatives was noted from mid to late season and attributed to the natural reduction in green pigments as the crop entered senescence. Canopy-scale photochemical reflectance index (PRI) was shown to be correlated with canopy radiation use efficiency (RUE). Mid-season water stress affected the relationship. Multiple years of data are required to demonstrate robust relationships between hyperspectral indices and corn ecophysiological status because of the interaction between environmental and nutrient stresses. Identifying areas of fields sensitive to weather-induced stresses will allow better management of N application. Timing the collection of hyperspectral image data at early and late vegetative phase could enhance precision agriculture by allowing supplemental nutrient application, identifying stress patterns and aid in yield forecasting. KW - Hyperspectral reflectance KW - Precision agriculture KW - Stress detection KW - Corn field KW - Radiation use efficiency KW - Chlorophyll KW - Leaf area index KW - Crop water content ER - TY - JOUR ID - underwood2003 AU - Underwood, Emma AU - Ustin, Susan AU - DiPietro, Deanne TI - Mapping nonnative plants using hyperspectral imagery UR - http://www.sciencedirect.com/science/article/pii/S0034425703000968 DO - 10.1016/s0034-4257(03)00096-8 T2 - Remote Sensing of Environment PY - 2003 SN - 0034-4257 VL - 86 IS - 2 SP - 150-161 AB - Nonnative plant species are causing enormous ecological and environmental impacts from local to global scale. Remote sensing images have had mixed success in providing spatial information on land cover characteristics to land managers that increase effective management of invasions into native habitats. However, there has been limited evaluation of the use of hyperspectral data and processing techniques for mapping specific invasive species based on their spectral characteristics. This research evaluated three different methods of processing hyperspectral imagery: minimum noise fraction (MNF), continuum removal, and band ratio indices for mapping iceplant (Carpobrotus edulis) and jubata grass (Cortaderia jubata) in California's coastal habitat. Validation with field sampling data showed high mapping accuracies for all methods for identifying presence or absence of iceplant (97%), with the MNF procedure producing the highest accuracy (55%) when the classes were divided into four different densities of iceplant. KW - AVIRIS KW - Hyperspectral KW - Invasive plants KW - Nonnative plants KW - Iceplant KW - Carpobrotus edulis KW - Jubata grass KW - Cortaderia jubata KW - Mapping ER - TY - JOUR ID - zarco-tejada_p_j_sepulcre-cant_2007 AU - Zarco-Tejada P.J. AU - Sepulcre-Cantó, G. TI - REMOTE SENSING OF VEGETATION BIOPHYSICAL PARAMETERS FOR DETECTING STRESS CONDITION AND LAND COVER CHANGES T2 - Estudios de la Zona No Saturada del Suelo PY - 2007 VL - 8 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 -