Showing papers in "Remote Sensing of Environment in 1994"

TL;DR: In this article, a modified SAVI (MSAVI) was proposed to increase the dynamic range of the vegetation signal while further minimizing the soil background influences, resulting in greater vegetation sensitivity as defined by a vegetation signal to soil noise ratio.

TL;DR: In this article, the authors proposed the vegetation index/temperature trapezoid, which combines spectral vegetation indices with composite surface temperature measurements to allow application of the crop water stress index (CWSI) theory to partially-vegetated fields without knowledge of foliage temperature.

TL;DR: The results illustrate the promise of narrow-band spectroradiometry for assessing the physiological state of vegetation and provide better physiological information than NDVI.

TL;DR: In this article, the influence of pixel heterogeneity, background, atmospheric and bidirectional effects on the relationship between fraction of photosynthetically active radiation absorbed by the photosynthesizing tissue in a canopy (FAPAR) and normalized difference vegetation index (NDVI) was investigated using a three-dimensional model of radiation transfer.

TL;DR: In this article, a set of criteria are established to evaluate their performance with respect to the vegetation signal and atmospheric and soil sources of noise, which form the basis for the evaluation and comparison of vegetation indices (VIs) across a wide range in vegetation covers.

TL;DR: In this paper, the relationship between transpiration coefficient and vegetation indices for wheat has been analyzed using a heat balance and a radiative transfer model, and the observed variations of crop (wheat) height, leaf area index, and weather conditions for 30 days at Phoenix (Arizona), together with the reflectances of different types of soil in wet and dry states, are used in the simulation.

TL;DR: In this paper, the authors examined the extent to which differences in the rate of soil moisture generation, as a function of soil type or locality, can account for these results and concluded that they cannot.

TL;DR: In this article, a change vector is defined as the vector difference between successive time-trajectories, each represented as a vector in a multidimensional measurement space, and its length indicates the magnitude of the interannual change, while its direction indicates the nature of the change.

TL;DR: In this paper, an analytical solution of the radiosity equation is applied to compute vegetation indices, reflectance spectra, and the spectral bidirectional reflectance distribution function for simple canopy geometries.

TL;DR: In this paper, the authors show that sufficiently high spectral resolution, of order 0.01 μm, would not be sufficient to discriminate virtually any soils, vegetation types, and rocks, but this is not necessarily the case.

TL;DR: In this paper, images of soybean canopies were obtained within selected narrow wavebands (6-10 nm bandwidths) to determine their capability for early detection of plant stress.

TL;DR: In this paper, a pulsed nitrogen laser emitting photons at a wavelength of 337 nm was used as a fluorescence excitation source to measure levels of plant stress that are of agronomic importance in corn.

TL;DR: In this article, a semi-empirical model is developed to represent the seasonal profile of the normalized difference vegetation index (NDVI) over temperate agricultural regions observed by NOAA / AVHRR local area coverage measurements where, due to 1.1 km resolution, pixels are mixtures of agricultural crop fields.

TL;DR: In this paper, the authors evaluated the impact of measurement scale and spatial aggregation on the information content and classification accuracies of airborne MEIS-II data acquired over a midlatitude temperate forested environment.

TL;DR: In this article, the authors measured canopy photosynthesis and light transmission in controlled-environment chambers and then transferred seedlings to a hemispheric illumination system where they measured canopy reflectance.

TL;DR: In this article, the relationship between radiometric surface temperature and spectral vegetation indices such as the NDVI over a tallgrass prairie in northeastern Kansas was studied, and it was found that the relationship was highly date and time-specific.

TL;DR: In this paper, the authors proposed and tested a method to identify the optimal spatial resolutions for detection and discrimination of coniferous classes in a temperate forested environment, based on the paradigm that there is an intricate relationship between the definition and the measurement of geographical entities and implies the following steps: 1) a priori define the geographical entities under investigation, 2)determine an optimization criterion for the choice of a sampling system, 3) progressively aggregate data acquired from a fine spatial sampling grid, 4) apply the optimization criterion on the series of spatially aggregated data

TL;DR: In this article, the authors analyzed airborne synthetic aperture radar (AIRSAR) imagery of forest, wetland, and agricultural ecosystems in northern Belize, Central America, and developed a four-level landscape hierarchy based upon clustering analyses of the 12 index parameters (four indices each for P, L, and C band) from two test site images.

TL;DR: In this article, the authors used an invertible forest canopy reflectance model to estimate the mean tree size and cover for each forest stand from an image segmentation system, and then sorted the stands into general growth forms using per-pixel image classification.

TL;DR: In this paper, high spectral resolution data from the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) acquired over several forest stands in west-central Oregon were analyzed with respect to variations in forest canopy biochemical content (kg ha−1), foliar biochemical concentration (mg cm2 leaf area), and leaf area index (LAI).

TL;DR: In this article, a simplified model for radiometric corrections has been used to improve nonsupervised classification of vegetation cover in a hilly area near Barcelona, Spain using a digital elevation model and standard parameters for exoatmospheric solar irradiance, atmospheric optical depth, and sensor calibration.

TL;DR: An exponential omnidirectional variogram model was used to characterize the spatial continuity of the image for use in the kriging algorithm and the error was shown to be 17% with no obvious spatial bias but with some tendency to categorize nonpasture as pasture (overestimation).

TL;DR: The Kappa statistic is shown to be a more discerning statistical tool for assessing the classification accuracy of different classifiers and has the added advantage of being statistically testable against the standard normal distribution.

TL;DR: In this paper, a one-dimensional turbid medium model of a vegetation canopy that includes specular reflection and the hot spot effect is used to calculate canopy bidirectional reflectance factors.

TL;DR: In this paper, the authors applied the visible and near-infrared analysis (VNIRA) methodology to the reflectance spectra of arid and semi-arid soils in the VIS-NIR (0.4-1.1 μm) spectral region.

TL;DR: In this paper, the authors used linear mixing models to estimate seasonal changes in inundation area over a 7-year period for a 34,550 km2 area along the Amazon River near Manaus.

TL;DR: In this paper, the error sources for three in-flight sensor calibration methods used by the Remote Sensing Group of the Optical Sciences Center at the University of Arizona are described and compared to those of the on-board lamp calibration system for a SPOT HRV camera.

TL;DR: In this paper, the authors assess the magnitude of bidirectional reflectance distribution (BRD) effects in AVHRR Channels 1 and 2 over land, their dependence on land cover, and the possibility of correcting for these effects as part of the AVHRr compositing process.

TL;DR: In this article, an energy balance model which relies primarily on remotely sensed inputs was used to extrapolate evapotranspiration (ET) estimates from one location containing near-surface meteorological data to other areas in the basin.

TL;DR: In this paper, a simple modification to the standard coastal zone color scanner (CZCS) atmospheric correction algorithm for application to Sea-viewing-wide field-of-view-sensor (SeaWiFS) is presented.