Aircraft Scanner Research Articles

Differential GPS Geometric Rectification of Fine-Resolution Aircraft Scanner Data

High-resolution aircraft or satellite data often require ground or im- age control for rectification of images, and this is best performed using control with a similar level of spatial resolution. To demonstrate the use of fine-resolution con- trol, advanced fine-resolution (4 m 3 4 m pixel) aircraft scanner data were geo- metrically corrected using high-order ground control points collected from a dif- ferential global positioning system (DGPS) experiment. A combination of corrections supplied by the aircraft data acquisition team, and DPGS points col- lected two years earlier allowed for a very high quality (root-mean square ' 1.000 m), fine-resolution image product.

Comparison of three calibration techniques for utilization of GER 63-channel aircraft scanner data of Makhtesh Ramon, Negev, Israel : E. Ben-Dor, F. A. Kruse, A. B. Lefkoff & A. Banin, Photogrammetric Engineering & Remote Sensing, 60(11), 1994, pp 1339–1354

Geophysical Environmental Research (GER) 63-channel aircraft scanner data were used to map the mineralogy at Makhtesh Ramon in the Negev area of southern Israel. The data were calibrated to apparent reflectance using three techniques; the flat field (FF) method, the empirical line (EL) method, and the internal average relative reflectance (IARR) method. Results of these calibrations were evaluated by extracting image spectra and comparing them to library spectra for pure minerals and to laboratory spectra of samples collected from the field area. These comparisons show that each calibration method produces apparent reflectance spectra that contain useful mineralogical information. Care must be taken, however, to avoid over interpretation, as all of these calibrations may produce spectral artifacts

Mineral mapping and vegetation removal via data-calibrated pixel unmixing, using multispectral images

Abstract In this paper an image unmixing process is described which is based on the assumption that pixel reflectance is a linear mix of component reflectances. Three stages are used initially to calibrate the multispectral data to shaded reflectance: (1) minimum value subtraction, (2) band-mean standardization and (3) reflectance-mean equalization. Using laboratory or field spectra, linear mixing equations are then solved for substance proportions. For a geological test site in North Queensland, Australia, two vegetation types (green and dry) and four mineral types (clay, haematite, goethite and quartz) were unmixed using NS001 aircraft scanner data. The six images created show the spatial abundance of individual vegetation and mineral types. The obscuring effect of both green and dry vegetation was removed from mineral maps by separately scaling up mineral proportions in each pixel. Unmixed mineral maps were used to locate potentially economic hydrothermal alteration zones. In addition, scaled mineral p...

Precipitable Water Estimation from High-Resolution Split Window Radiance Measurements

A technique that uses the spatial variance of image brightness temperature to derive total column precipitable water is applied to high-resolution multispectral aircraft scanner data for the June 19, 1986 COHMEX day. The technique has several advantages over other approaches in that it requires only relative calibration accuracy, is less susceptible to instrument error, and does not directly use a priori information. Results indicate significant horizontal variability of precipitable water at the mesoscale. Precipitable water gradients of 6 mm per 10 km are not uncommon. The results verify well against special rawinsonde measurements and the ensuing cloud field development. While only applied to this specialized aircraft data, the applicability of the technique to operational AVHRR and VAS data is discussed.

Robotic aircraft scanner for neutron radiographic inspection 38210 Orphan, V.J.; Maung, T. Proceedings of the 35th Conference on Remote Systems Technology, Los Angles, California (United States), Nov. 1987. pp. 195–199 American Nuclear Society, 1988

Robotic aircraft scanner for neutron radiographic inspection 38210 Orphan, V.J.; Maung, T. Proceedings of the 35th Conference on Remote Systems Technology, Los Angles, California (United States), Nov. 1987. pp. 195–199 American Nuclear Society, 1988

Robotic aircraft scanner for neutron radiographic inspection : Orphan, V.J.; Maung, T. Proceedings of the 35th conference on remote systems technology, Los Angeles, California (United States), Nov. 1987. pp. 195–199 American nuclear society, 1988.

Robotic aircraft scanner for neutron radiographic inspection : Orphan, V.J.; Maung, T. Proceedings of the 35th conference on remote systems technology, Los Angeles, California (United States), Nov. 1987. pp. 195–199 American nuclear society, 1988.

Tropical forest biomass and successional age class relationships to a vegetation index derived from landsat TM data

Forest stand structure and biomass data were collected using conventional forest inventory techniques in tropical, subtropical, and warm temperate forest biomes. The feasibility of detecting tropical forest successional age class and total biomass differences using Landsat-Thematic mapper (TM) data, was evaluated. The Normalized Difference Vegetation Index (NDVI) calculated from Landsat-TM data were not significantly correlated with forest regeneration age classes in the mountain terrain of the Luquillo Experimental Forest, Puerto Rico. The low sun angle and shadows cast on steep north and west facing slopes reduced spectral reflectance values recorded by TM at orbital altitude. The NDVI, calculated from low altitude aircraft scanner data, was significantly correlated with forest age classes. However, analysis of variance suggested that NDVI differences were not detectable for successional forests older than approximately 15–20 years. Also, biomass differences in young successional tropical forest were not detectable using the NDVI. The vegetation index does not appear to be a good predictor of stand structure variables (e.g., height, diameter of main stem) or total biomass in uneven age, mixed broadleaf forest. Good correlation between the vegetation index and low biomass in even age pine plantations were achieved for a warm temperate study site. The implications of the study for the use of NDVI for forest structure and biomass estimation are discussed.

Geological remote sensing of rocky coasts

AbstractFrom remotely sensed images of rock surfaces at coasts it is possible to map some characteristics of different rock types. To do this a selection must be made of those parts of the image that correspond to the rock surfaces prior to interrogation of their geological information content. A comparative study of satellite-acquired multispectral Thematic Mapper data and aircraft-acquired multispectral scanner data at four test sites on the Pembrokeshire coast was made. The spatial resolution of the Thematic Mapper data (30 m) proved to be too coarse to provide any continuity of mapping over several kilometres of rock exposures, whereas the 10 m resolution of the aircraft data was adequate to do this. Using the aircraft scanner data, neighbouring Old Red Sandstone and Carboniferous (mainly carbonate) rocks could be discriminated in both three-band and principal components images. Furthermore, it proved possible to distinguish between limestone and dolomite lithologies in the Carboniferous succession and between some of the mudstones and sandstones in the Old Red Sandstone. Airborne multispectral scanning of rocky coasts is a new potential tool for geological mapping in exploration projects in which it would be best integrated with the acquisition of airborne geophysical and field geological data.

Aircraft and satellite remote sensing of desert soils and landscapes

The remote sensing of desert soils and landscapes using Thematic Mapper (TM), Heat Capacity Mapping Mission (HCMM), Simulated SPOT, and Thermal Infrared Multispectral Scanner (TIMS) data is discussed. These studies were all conducted in arid or semiarid study sites. Landsat Thematic Mapper (TM) data for southwestern Nevada discriminated among alluvial fan deposits with different degrees of desert pavement and varnish as well as different vegetation cover. Thermal-infrared data acquired from the Heat Capacity Mapping Mission (HCMM) satellite were used to map the spatial distribution of diurnal surface temperatures and to estimate mean annual soil temperatures in semiarid east central Utah using diurnal data for five dates throughout a year. Simulated SPOT data for northwestern New Mexico identified geomorphic features, such as differences in eolian sand cover and fluvial incision, which are correlated with surface age and geomorphic stability of landscape components. The Thermal Infrared Multispectral Scanner (TIMS), which is an aircraft scanner that provides six-channel spectral capability in the thermal region of the electromagnetic spectrum, was used to depict surface geologic features of the Saline Valley in southeastern California. These research projects are presented as a summary of some of the sensors and analytical techniques that are useful in the study of desert soils and landscapes.

Review Article A review of multi-channel indices of class separability

Abstract An increasingly common question arising in processing digital multi-channel data from spacecraft and aircraft scanner systems is “which channels contain the best information to separate the classes of interest to the user?”. This may be to identify the best single channel for separating classes in a black and white photographic or line printer output product, or the best three channels for a colour photographic presentation of the data, or the best ‘n’ channels to enter into a classification (being mindful of the ‘trade off’ between improved sub-class separability and increasing usage of computer space and time resources). The only valid way to approach separability using more than one channel is to consider it in multi-channel space utilizing the inter-channel relationship terms. Having defined the classes using some form of hierarchical ordering approach, such as that proposed by Anderson et al. (1972), the user may compile the statistical profiles of the classes of interest from the sensor mul...

Land-Use Mapping Using Edge Density Texture Measures on Thematic Mapper Simulator Data

Texture analysis was performed as part of an investigation of the information content of Landsat Thematic Mapper (TM) imagery. High-altitude aircraft scanner imagery from the Airborne Thematic Mapper (ATM) instrument was acquired over central California and used to simulate TM data. Edge density texture images were constructed by computation of proportions of edge pixels in a 31×31 moving window on a near-infrared ATM band. A training technique was employed to select computational parameters to maximize the difference between edge density measurements in urban and in rural areas. The results of classification of the texture images showed that urban and rural areas could be distinguished with texture alone, indicating that inclusion of texture in automated classification procedures could significantly improve their accuracy.

Middle infrared multispectral aircraft scanner data: analysis for geological applications

Multispectral middle IR (8-13-microm) data were acquired with an aircraft scanner over Utah. Because these digital image data were dominated by temperature, all six channels were highly correlated. Extensive processing was required to allow geologic photointerpretation based on subtle variations in spectral emittance between rock types. After preliminary processing, ratio images were produced and color ratio composites created from these. Sensor calibration and an atmospheric model allowed determination of surface brightness, temperature, emittance, and color composite emittance images. The best separation of major rock types was achieved with a principal component transformation, followed by a Gaussian stretch, followed by an inverse transformation to the original axes.

Evaluation of multispectral middle infrared aircraft images for lithologic mapping in the East Tintic Mountains, Utah

Six channels of multispectral middle infrared (8 to 14 micron) aircraft scanner data were acquired over the East Tintic mining district, Utah. This area has high relief and moderate vegetation and consists mainly of Tertiary silicic igneous rocks and Paleozoic quartzite and carbonate rocks that have been locally hydrothermally altered. These digital-image data were computer processed to create a color-composite image based on principal component transformations. Color differences in this image are related to the spectral differences in the surface material and allow discrimination of several rock types, depending primarily on their silica content. When combined with a visible and near infrared color-composite image from a previous flight, with limited field checking, it is possible to discriminate quartzite, carbonate rocks, quartz latitic and quartz monzonitic rocks, latitic and monzonitic rocks, silicified altered rocks, argillized altered rocks, and vegetation.

Mapping of hydrothermal alteration in the Cuprite mining district, Nevada, using aircraft scanner images for the spectral region 0.46 to 2.36µm

Color composites of Landsat Multispectral Scanner ratio images that display variations in the intensity of ferric-iron absorption bands are highly effective for mapping limonitic altered rocks but are ineffective for mapping nonlimonitic altered rocks. Analysis of 0.45- to 2.5-µm field and laboratory spectra shows that iron-deficient opalized rocks in the Cuprite mining district, Nevada, have an intense OH-absorption band near 2.2 µm, owing to their content of clay minerals and alunite, and that this spectral feature is absent or weak in adjacent unaltered tuff and basalt. Altered rocks in the district can be discriminated from unaltered rocks with few ambiguities by use of color-ratio composite images derived from multispectral (0.46 to 2.36 µm) aircraft data. In addition, some effects of mineralogical zoning can be discriminated within the altered area. Only variations in amounts of limonite can be discerned in shorter wavelength aircraft data, Landsat Multispectral Scanner bands, and color aerial photographs.