Airborne Multispectral Scanner Research Articles

The interactive effect of spatial resolution and degree of internal variability within land-cover types on classification accuracies

Abstract A study is made to assess the effect of spatial resolution on the degree of internal variability within land-cover classes and then to examine how this within-class variance affects classification accuracy. Airborne Multispectral Scanner data flown at 5 m resolution are degraded to simulate 10 and 20 m data. Classification accuracies within internally homogeneous classes are found to be high at all spatial resolutions. In contrast, classification accuracies of land-cover types characterized by a high degree of internal variability or scene noise improve by up to 20 per cent as spatial resolution is coarsened because the proportion of scene noise is reduced. A further improvement in classification can be achieved by smoothing the imagery prior to classification using various spatial filters. The extent of this improvement was found to be as much as 25 per cent depending on the type of spatial filter used, the window size of the filter, the spatial resolution of the data and the land-cover type bei...

1B. Developmental Study on New Airborne Multispectral Scanner System Specifically Oriented to Thermal Observation of Volcanoes

1B. Developmental Study on New Airborne Multispectral Scanner System Specifically Oriented to Thermal Observation of Volcanoes

Airborne MSS data to estimate GLAI

Abstract Airborne multispectral scanner ( MSS) data, collected in June 1984, were used to estimate the green leaf area index ( GLAI) for 60 km2 of grassland. The methodology involved (i) radiometric and atmospheric correction, (ii) production of a vegetation index image, (iii) calculation of a calibration relationship between a vegetation index and GLAI, (iv) production of an image of estimated GLAI by inversion of the calibration relationship in (iii), and (v) accuracy assessment. The initial accuracy of GLAI estimation was ± 0-75 GLAI for an area and 17-40 per cent at the 95 per cent confidence level, for a six-class classification. Refinements to the methodology were evaluated by their effect upon the accuracy of GLAI estimation. In order of increasing importance these refinements were: suppression of environmental effects on the remotely sensed data, processing on a per-field rather than a per-pixel basis, calculation of the calibration relationship between a vegetation index and GLAI, using ground-ba...

The application of airborne remote sensing to the detection of solution features in limestone

Abstract Airborne remote sensing techniques have been developed for the detection of collapse and subsidence features in chalk and other limestone rocks. The detection of such features in the early stages of an engineering project is of crucial importance if serious geotechnical problems to building construction and public safety are to be avoided. Particular attention is paid to the potential of airborne multispectral scanner (MSS) and thermal infrared (IR) data as a means of detection. Background information is also provided concerning a project to obtain multitemporal thermal IR data over two test sites on the Cretaceous Chalk outcrop of southern England.

Multispectral remote sensing of nearshore suspended sediments: a pilot study

The till that comprises the coastal cliffs at Holderness is being eroded and transported southwards by waves and currents within the nearshore zone. As a first step towards estimating the magnitude of this movement, airborne multispectral scanner data were collected. The spectral radiance ( Lλ ) recorded by this sensor was positively correlated with the suspended sediment concentration ( SSC) at the 95 percent confidence level. However, when the relationships between SSC and Lλ were inverted for the estimation of SSC, errors of the order of 343-494 percent were observed. It is recommended that for future studies there is a need to reduce the errors consequent upon the areal, vertical and temporal variability in SSC, the problems of inversion and the presence of white-caps.

Remote sensing - a new tool in exploration geology

Remote sensing techniques have been applied to mineral exploration in areas of South and East Greenland. The data consist of airborne and satellite-borne (Landsat) multispectral scanner images and geochemical and geophysical measurements interpolated into grid format and registered on the Landsat images. The main image processing methods applied include ratioing, principal component transformation/factor analysis and classification. In addition, visual and subsequent statistical analyses of lineaments were carried out on images from South Greenland. The results of the work include mapping of several hundred spectral anomalies which represent oxidation zones on the ground. The lineament analysis resulted in definition of major linear zones with increased lineament intensities; some of these zones may have geological significance. Supervised classification was carried out on an integrated data set consisting of images and geochemical/geophysical data. The training areas mainly included uranium showings, and the classified image depicts both previously known occurrences and a new area which is statistically similar to the training areas.

Sample size for ground and remotely sensed data

Sampled data are used to calibrate and determine the accuracy of both remotely sensed data and the products of remotely sensed data. This paper discusses the problems of achieving a balance between the size and the error of these samples, not at the level of the scene but at the level of the sites within that scene. Using an area of limestone grassland as an illustrative example, the sample size required to characterize a wide range of grassland fields was determined. With a maximum of 5% error at the 95% confidence level the minimum sample size per field was noted to vary between 1–58 for ground radiometric and airborne multispectral scanner measurements and 142–293 for green leaf area index measurements. The collection of such large sample sizes is unusual in remote sensing. This review concludes that there is a need for an increased awareness of the magnitude of the sampling error and an attempt should be made to use the known spatial autocorrelation in the data to reduce error for a given sample size.

Assessing impacts of off-nadir observation on remote sensing of vegetation: use of the Suits model

The use of Suits' (1972a, b) digital radiative transfer model to simulate the effect of nonLambertian canopy reflectance on off-nadir observations of vegetation is discussed. Canopy reflectances of cord grass are calculated using the radiative transfer model, field radiometric measurements, and airborne multispectral scanner data. The effects of varying view angles on canopy reflectance are analyzed and compared. The comparison reveals that the model is effective in simulating the sense and magnitude of reflectance change due to variable angles of observations; however, the model does not reproduce the observed dependence of nadir canopy reflectance on solar zenith angle. It is concluded that the radiative transfer model is applicable for predicting the variation in canopy reflectance due to changing view zenith angles.

APPLICATION OF AIRBORNE MSS DATA TO GEOMORPHOLOGICAL AND GEOLOGICAL SURVEYS FOR ROAD CONSTRUCTION IN MOUNTAINOUS AREA

The construction of a new expressway in mountainous areas requires cutting off slopes and crossing over desolated valleys throughout the areas. For the purpose of rational design and performance of such a road, a considerable amount of information has to be acquired on the nature of the terrain through which the road will be built. This paper discusses the value of using the remote sensing technique for geomorphological and geological surveys recently undertaken for a highway in Kyushu district in the southern part of Japan. Remote sensing data used for analysis were obtained with a multispectral scanner (MSS) on board an airplane. These data are analyzed both analogly and digitally in comparison with results from interpretation of aerial photographs and direct reconnaissance surveys.

Evaluation of LANDSAT and airborne multispectral data and aerial photographs for mapping forest features and phenomena in a part of the Godavari basin

Abstract The automatic interpretation of multispectral digital data obtained from LANDSAT as well as from an airborne multispectral scanner using an interactive computer system and visual interpretation of colour composites of LANDSAT imagery and aerial photographs of a dry deciduous forest tract were used for evaluating the discrimination capabilities of each technique and for comparative evaluation. While visual interpretation of LANDSAT imagery could give only general information, such as contiguity of vegetation cover, digital analysis of the same yielded more detailed information, such as teak-bearing and non-teak-bearing regions. The analysis of airborne multispectral data, in the present state of the art, for performing forest surveys and making maps is limited. Aerial photographs are very useful for mapping forest land features and stock, which can be done more reliably than could be done by ground surveys. Infrared photographs show better promise in mapping forest features. The integration of mul...

航空機マルチスペクトルスキャナー（ＭＳＳ）データによる三宅島噴火災害の解析

航空機マルチスペクトルスキャナー（ＭＳＳ）データによる三宅島噴火災害の解析

A summary of the history of the development of automated remote sensing for agricultural applications

Advancing the techniques for machine processing of satellite-acquired multispectral data has been a major thrust of an element of the U.S. civilian remote sensing research program since the 1960's. The program's primary focus has been the use of multispectral data to identify type, condition, and ontogenetic stages of cultural vegetation. The research began as a result of a National Academy of Science study on the applicability of remote monitoring. It was given impetus by the mid-1960s introduction of the first airborne multispectral scanner (MSS) by the University of Michigan. The MSS spawned research by Purdue and others that led to design simulations for the first earth resources satellite in 1969. In 1970, an airborne MSS was used in the Corn Blight Watch — the first large-scale application of remote sensing in agriculture. During 1972 and 1973, research established the feasibility of automating digital classification to process high volumes of Landsat MSS data. The Large Area Crop Inventory Experiment (LACIE) successfully demonstrated automated processing of Landsat MSS data in estimating wheat crop production on a global basis. This experience led to AgRISTARS program designed to address the technical issues defined by LACIE, to investigate other portions of the electromagnetic spectrum and expand the technology to several key commercial crops in important agricultural areas worldwide.

Relationships between the type of residential area and the aspects of surface temperature and solar reflectance (based on digital image analysis using airborne multispectral scanner data)

Relationships between the type of residential area and the aspects of surface temperature and solar reflectance (based on digital image analysis using airborne multispectral scanner data)

Spring wheat-leaf phytomass and yield estimates from airborne scanner and hand-held radiometer measurements†

An attempt has been made to relate hand-held radiometer measurements, and airborne multispectral scanner readings, with both different wheat stand densities and grain yield. Aircraft overflights were conducted during the tillering, stem extension and heading period stages of growth, while hand-held radiometer readings were taken throughout the growing season. The near-IR/red ratio was used in the analysis, which indicated that both the aircraft and the ground measurements made possible a differentiation and evaluation of wheat stand densities at an early enough growth stage to serve as the basis of management decisions. The aircraft data also corroborated the hand-held radiometer measurements with respect to yield prediction. Winterkill was readily evaluated.

Directional reflectance properties determined by analysis of airborne multispectral scanner data and atmospheric correction

Directional reflectance properties of natural surfaces are very important in the interpretation of remotely sensed data. The analysis of multispectral scanner data shows a distinct dependence on scan angle, wavelength (0.4–1.1 μm), and classes (e.g., bare soil, vegetation). This relationship can be described by polynomials determined by regression methods. Atmospheric effects are computed with a simple model by parametrization of the multiple scattered skylight. The model permits a quick and sufficient estimation of the airlight, depending on the data collection conditions. Comparisons of the scanner data with the corresponding model yield the following results: The differences between airborne and ground measurements are due to atmospheric effects. The directional variation in brightness is mainly caused by the object itself with the exception of short wavelengths and/or a very low albedo. The hue shift of vegetation is essentially produced by the object and modified by the atmosphere. Taking into account the directional reflectance properties in a direction-dependent classification procedure results in an improvement of up to 20% in comparison with algorithms used so far. Quantitative relationships between ground measurements and radiation measurements by airborne sensors including atmospheric effects can be determined with the proposed methods.

Surface material mapping in the English Fenlands using airborne multispectral scanner data

Abstract Three approaches have been adopted to assess the importance of individual spectral bands in data from an airborne multispectral scanner flown over part of the English Fenlands; these involve (i) an analysis of the interrelationships between the spectral bands, (ii) a study of the spectral response of materials and (iii) a study of the relationships between physical properties of materials and their spectral responses. Results indicate that where exposed surface materials are found, all spectral bands are strongly positively correlated (r>0.866) with one another, apart from the thermal band 11 which is negatively correlated (r < -0.73) with all other bands. Study of the spectral response of materials suggests that the two middle-infrared bands, 9 and 10, reveal the greatest spectral range and variability, providing maximum contrast in relation to changes in surface material. Additionally, the thermal band 11 is found to be the best discriminator between the sandy central-channel material and surro...

The estimation of green-leaf-area index from remotely sensed airborne multispectral scanner data

Abstract Airborne multispectral scanning system (MSS) data from the Natural Environment Research Council's MSS-82 project were used to estimate the green-leaf-area index (GLAI) of an area of semi-natural and agricultural limestone grassland. This research is the pilot study of a five phase investigation which will ultimately test the feasibility of using airborne and spaceborne MSS data to estimate GLAI over large areas. The pilot study was designed around four stages: (i) derivation of the relationship between multispectral reflectance and vegetation amount using ground radiometric data collected in the field, (ii) production of a perpendicular-vegetation index (PVI) image, (iii) production of a GLAI image using the relationship between PVI and GLAI and (iv) accuracy assessment of the resultant GLAI image. Due to a number of project- and environment-specific problems the proposed methodology was modified and GLAI was predicted to an accuracy of 50-86 per cent at the 95 per cent confidence level. For the ...

Effects of off-nadir view angles on the detected spectral response of vegetation canopies

Abstract The effect of view angle upon the detected spectral response of vegetation canopies is studied, using NERC 1982 airborne multispectral scanner campaign data. An attempt is made to distinguish between the effects of atmosphere and the anisotropic reflectance of vegetation canopies. The influence of atmospheric backscatter is found to be greatest at very short wavelengths (0.42-0.45 μm) Preliminary results confirm that the detected spectral response of vegetation canopies varies with view angle and that the nature and extent of these variations are wavelength-dependent and cover-type dependent. In general, direction-dependent reflectance is symmetric about the nadir value for the visible wavebands, but is manifestly asymmetric in the far-red to near-infrared wavebands. Off-nadir effects for vegetation canopies are found to be smallest in the middle-infrared wavebands.

Infrared Romote Sensing for Soil Moisture Measurement with Airborne Multispectral Scanner

The relation between thermal infrared data obtained by airborne MSS measurements and soil moisture content in the Kujukuri Coastal Plain has been investigated.The results are as follows.1) Not only the rising rate or variation of the surface radiant temperature but also the surface radiant temperature itself is closely correlated with soil moisture content.2) For the estimation of soil moisture content based on the thermal infrared data, application of the exponential decay curve or the linear model with the logarithmic transforming for straightness seems to be preferable rather than that of the linear model with the original data, in consideration of the statistical processing and physical properties of the soil. Though the selection of an appropriate model is difficult at a present, the problem should be resolved as a result of future analyses.3) The moisture content of sandy soil can be estimated on the basis of surface radiant temperature and its rising rate for appropriate periods in a half day. However, for the establishment of soil moisture estimation models in the remote sensing, parameters free from several soil physical properties such as soil textural class, content of certain minerals, porosity, roughness of soil surface, the time of measurement and regional differences, should be developed through normalization using some weather elements which affect the variation of the soil surface temperature physically.4) Similar experimental studies in other areas and other seasons are necessary for the establishment of the measurement system desired by this study.

Use of multispectral scanner images for assessment of hydrothermal alteration in the Marysvale, Utah, mining area

Airborne multispectral scanner. A color composite image was constructed using the following spectral band ratios: 1.6/2.2 mu m, 1.6/0.48 mu m, and 0.67/1.0 mu m. The color ratio composite successfully distinguished most types of altered rocks from unaltered rocks; further division of altered rocks into ferric oxide-rich and -poor types.--Modified journal abstract.