Showing papers on "VNIR published in 2010"

A Novel Method to Estimate Subpixel Temperature by Fusing Solar-Reflective and Thermal-Infrared Remote-Sensing Data With an Artificial Neural Network

Abstract: Among the multisource data fusing methods, the potential advantages of remote sensing of solar-reflective visible and near-Infrared [(VNIR); 400-900 nm] data and thermal-infrared (TIR) data have not been fully mined. Usually, a linear unmixed method is used for the purpose, which results in low estimation accuracy of subpixel land-surface temperature (LST). In this paper, we propose a novel method to estimate subpixel LST. This approach uses the characteristics of high spatial-resolution advanced spaceborne thermal emission and reflection radiometer (ASTER) VNIR data and the low spatial-resolution TIR data simulated from ASTER temperature product to generate the high spatial-resolution temperature data at a subpixel scale. First, the land-surface parameters (e.g., leaf area index, normalized difference vegetation index (NDVI), soil water content index, and reflectance) were extracted from VNIR data and field measurements. Then, the extracted high resolution of land-surface parameters and the LST were simulated into coarse resolutions. Second, the genetic algorithm and self-organizing feature map artificial neural network (ANN) was utilized to create relationships between land-surface parameters and the corresponding LSTs separately for different land-cover types at coarse spatial-resolution scales. Finally, the ANN-trained relationships were applied in the estimation of subpixel temperatures (at high spatial resolution) from high spatial-resolution land-surface parameters. The two sets of data with different spatial resolutions were simulated using an aggregate resampling algorithm. Experimental results indicate that the accuracy with our method to estimate land-surface subpixel temperature is significantly higher than that with a traditional method that uses the NDVI as an input parameter, and the average error of subpixel temperature is decreased by 2-3 K with our method. This method is a simple and convenient approach to estimate subpixel LST from high spatial-temporal resolution data quickly and effectively.

Optimized identification of worldwide radiometric pseudo-invariant calibration sites

Abstract: Long-term radiometric stability monitoring of visible and near-infrared Earth observing sensors has been enhanced over the past decade through the use of pseudo-invariant calibration sites on the Earth's surface. Significant work has been done to characterize sites primarily in the Sahara and Middle East desert regions, with some additional work at other locations throughout the world. The work described in this paper attempts to locate those sites that can be considered optimal from a temporal stability measure. To accomplish this, an invariant site identification algorithm was developed that can locate a statistically optimal region in an automated fashion. Results generated from studying virtually all previously identified pseudo-invariant sites indicate that there are six sites in the Sahara and Middle East that can achieve variabilities as low as 2% in the visible and near infrared (VNIR) and 2%–3% in the shortwave infrared (SWIR). The Sonoran Desert site was identified in North America and produces ...

Japanese hyper-multi spectral mission

Abstract: The hyperspectral and the multispectral (hyper-multi spectral) mission is the Japanese next generation space-borne radiometer development project. This project is a heritage from ASTER launched in December 1999. The performance of the hyperspectral radiometer is 30m ground sampling distance, 30km swath width, 10nm and 12.5nm wavelength distance for VNIR and SWIR respectively, over 450@620nm and 300@2,100nm of the signal to noise (S/N) ratio. The performance of the multispectral radiometer is 5m ground sampling distance, 90km swath width, over 200 for all bands of S/N ratio. This project will be launched on ALOS-3 of JAXA in FY2014. The panchromatic sensor with stereo viewing will also be installed on ALOS-3.

Aerosol Optical Retrieval and Surface Reflectance from Airborne Remote Sensing Data over Land

Abstract: Quantitative analysis of atmospheric optical properties and surface reflectance can be performed by applying radiative transfer theory in the Atmosphere-Earth coupled system, for the atmospheric correction of hyperspectral remote sensing data. This paper describes a new physically-based algorithm to retrieve the aerosol optical thickness at 550nm (τ550) and the surface reflectance (ρ) from airborne acquired data in the atmospheric window of the Visible and Near-Infrared (VNIR) range. The algorithm is realized in two modules. Module A retrieves τ550 with a minimization algorithm, then Module B retrieves the surface reflectance ρ for each pixel of the image. The method was tested on five remote sensing images acquired by an airborne sensor under different geometric conditions to evaluate the reliability of the method. The results, τ550 and ρ, retrieved from each image were validated with field data contemporaneously acquired by a sun-sky radiometer and a spectroradiometer, respectively. Good correlation index, r, and low root mean square deviations, RMSD, were obtained for the τ550 retrieved by Module A (r2 = 0.75, RMSD = 0.08) and the ρ retrieved by Module B (r2 ≤ 0.9, RMSD ≤ 0.003). Overall, the results are encouraging, indicating that the method is reliable for optical atmospheric studies and the atmospheric correction of airborne hyperspectral images. The method does not require additional at-ground measurements about at-ground reflectance of the reference pixel and aerosol optical thickness.

Biometric study using hyperspectral imaging during stress

Abstract: To the casual observer, transient stress results in a variety of physiological changes that can be seen in the face. Although the conditions can be seen visibly, the conditions affect the emissivity and absorption properties of the skin, which imaging spectrometers, commonly referred to as Hyperspectral (HS) cameras, can quantify at every image pixel. The study reported on in this paper, using Hyperspectral cameras, provides a basis for continued study of HS imaging to eventually quantify biometric stress. This study was limited to the visible to near infrared (VNIR) spectral range. Signal processing tools and algorithms have been developed and are described for using HS face data from human subjects. The subjects were placed in psychologically stressful situations and the camera data were analyzed to detect stress through changes in dermal reflectance and emissivity. Results indicate that hyperspectral imaging may potentially serve as a non-invasive tool to measure changes in skin emissivity indicative of a stressful incident. Particular narrow spectral bands in the near-infrared region of the electromagnetic spectrum seem especially important. Further studies need to be performed to determine the optimal spectral bands and to generalize the conclusions. The enormous information available in hyperspectral imaging needs further analysis and more spectral regions need to be exploited. Non-invasive stress detection is a prominent area of research with countless applications for both military and commercial use including border patrol, stand-off interrogation, access control, surveillance, and non-invasive and un-attended patient monitoring.

Integrating visible, near-infrared and short-wave infrared hyperspectral and multispectral thermal imagery for geological mapping at Cuprite, Nevada: a rule-based system

Abstract: Previous research has shown that integrating hyperspectral visible and near-infrared (VNIR) / short-wave infrared (SWIR) with multispectral thermal infrared (TIR) data can lead to improved mineral and rock identification. However, inconsistent results were found regarding the relative accuracies of different classification methods for dealing with the integrated data set. In this study, a rule-based system was developed for integration of VNIR/SWIR hyperspectral data with TIR multispectral data and evaluated using a case study of Cuprite, Nevada. Previous geological mapping, supplemented by field work and sample spectral measurements, was used to develop a generalized knowledge base for analysis of both spectral reflectance and spectral emissivity. The characteristic absorption features, albedo and the location of the spectral emissivity minimum were used to construct the decision rules. A continuum removal algorithm was used to identify absorption features from VNIR/SWIR hyperspectral data only; spectral angle mapper (SAM) and spectral feature fitting (SFF) algorithms were used to estimate the most likely rock type. The rule-based system was found to achieve a notably higher performance than the SAM, SFF, minimum distance and maximum likelihood classification methods on their own.

Atmospheric compensation of thermal infrared hyperspectral imagery with the emissive empirical line method and the in-scene atmospheric compensation algorithms: a comparison

Abstract: The in-scene atmospheric compensation (ISAC) algorithm of Young et al. (2002) [14] (and as implemented in the ENVI® software system [16] as 'Thermal Atm Correction') is commonly applied to thermal infrared multi- and hyperspectral imagery (MSI and HSI, respectively). ISAC estimates atmospheric transmissivity and upwelling radiance using only the scene data. The ISAC-derived transmissivity and upwelling radiance are compared to those derived from the emissive empirical line method (EELM), another in-scene atmospheric compensation algorithm for thermal infrared MSI and HSI data. EELM is based on the presence of calibration targets (e.g., panels, water pools) captured in the spectral image data for which the emissivity and temperature are well known at the moment of MSI/HSI data acquisition. EELM is similar in concept to the empirical line method (ELM) algorithm commonly applied to visible/near-infrared to shortwave infrared (VNIR/SWIR) spectral imagery and is implemented as a custom ENVI® plugin application. Both ISAC and EELM are in-scene methods and do not require radiative transfer modeling. ISAC and EELM have been applied to airborne longwave infrared (LWIR; ~7.5 μm to ~13.5 μm) HSI data. Captured in the imagery are calibration panels and/or water pools maintained at different temperatures facilitating the application of EELM. Overall, the atmospheric compensation parameters derived from the two methods are in close agreement: the EELM-derived ground-leaving radiance spectra generally contain fewer residual atmospheric spectral features, although ISAC sometimes produces smoother ground-leaving radiance spectra. Nonetheless, the agreement is viewed as validation of ISAC. ISAC is an effective atmospheric compensation algorithm that is readily available to the remote sensing community in the ENVI® software system. Thus studies such as the present testing and comparing ISAC to other methods are important. The ISAC and EELM algorithms are discussed as are the airborne LWIR and simulated HSI data to which they are applied. Also presented are analyses and comparisons of the retrieved transmissivity and upwelling radiance terms.

Rainwater path in warm clouds derived from combined visible/near‐infrared and microwave satellite observations

Abstract: [1] The effects of warm rain on optical properties of clouds in the visible/near‐infrared (VNIR) and passive microwave (PMW) are studied using a simple conceptual cloud model. It is shown that the combined use of PMW and VNIR observations allows for the detection of precipitation and the derivation of rainwater path utilizing the different physical information content of the two observation types. Various potential error sources are studied and one month of combined geostationary visible/near infrared and Advanced Microwave Scanning Radiometer‐EOS (AMSR‐E) passive microwave observations off the coast of South Africa are evaluated using the proposed approach. Comparisons with CloudSat radar reflectivities are used for an independent assessment. A gradual increase in retrieved rainwater path with column maximum radar reflectivity is found for reflectivity values larger than −10 dBz. For monthly mean values at 1 × 1 degree resolution, rainwater path is correlated with in‐cloud liquid water path (R 2 = 0.50). The strongest correlation (R 2 = 0.69) exists between rainwater path and the inverse of cloud droplet number concentration (N). This finding is consistent with other studies supporting a 1/N dependency of precipitation intensity on cloud droplet number concentration in warm clouds.

VNIR Spectroscopy Estimates of Within-Field Variability in Soil Properties

Abstract: Over the last three decades or more, researchers have estimated soil properties using visible and near-infrared (VNIR) diffuse reflectance spectroscopy (DRS), with varying results. Using VNIR DRS for estimating soil property variation within fields is particularly challenging, because in many cases the variation in the property of interest may be relatively small and because of the need to deal with spatially correlated data. In this study, we used VNIR DRS to estimate the variability in soil physical and chemical properties within a typical production field in north-east Missouri, USA. Soil samples were obtained to 15 cm depth on a 30 m grid spacing, plus at a number of random sampling locations. Laboratory analyses were conducted for sand, silt, and clay fractions, organic matter, pH, P, K, Ca, Mg, and cation exchange capacity (CEC). VNIR reflectance of dried and sieved samples was obtained in the laboratory using a spectrometer with a wavelength range from 350 to 2,500 nm. Partial least squares (PLS) regression was used to estimate soil properties from spectra, both for the full range and for subset wavelength ranges above and below 1,000 nm. A regression kriging approach was used to account for spatial dependence. We found that for these soils, an NIR-only instrument (1,000–2,500 nm) would be able to quantify CEC, organic matter, and texture with accuracy similar to that from a VNIR (350–2,500 nm) instrument. Some soil properties, including CEC and pH, were well estimated with PLS regression, while others, including organic matter, were not. Coupling regression kriging with PLS regression improved estimates in some cases, but was not as effective as has been reported in some other studies. More advanced calibration methods should be investigated for their ability to improve within-field VNIR DRS results on these soils.

Multisensor airborne imagery collection and processing onboard small unmanned systems

Abstract: FEATHAR (Fusion, Exploitation, Algorithms, and Targeting for High-Altitude Reconnaissance) is an ONR funded effort to develop and test new tactical sensor systems specifically designed for small manned and unmanned platforms (payload weight < 50 lbs). This program is being directed and executed by the Naval Research Laboratory (NRL) in conjunction with the Space Dynamics Laboratory (SDL). FEATHAR has developed and integrated EyePod, a combined long-wave infrared (LWIR) and visible to near infrared (VNIR) optical survey & inspection system, with NuSAR, a combined dual band synthetic aperture radar (SAR) system. These sensors are being tested in conjunction with other ground and airborne sensor systems to demonstrate intelligent real-time cross-sensor cueing and in-air data fusion. Results from test flights of the EyePod and NuSAR sensors will be presented.

[Study on the prediction of soil heavy metal elements content based on mid-infrared diffuse reflectance spectra].

Abstract: The present paper analyzed the possibility of mid-infrared diffuse reflectance spectra for quick assessment of heavy metal element content in soil quickly Soil samples were collected from Jiangning District and Baguazhou Island, and the numbers of sample were 103 and 58 separately Jiangning District samples were used as calibration set while Baguazhou Island samples as validation set To assess the utility of different pre-treatment process of MIR spectroscopy for soil heavy metal element content analysis, we used PLSR method to develop the calibration between spectral data and soil elements content Three spectral pretreating techniques such as smooth, log(1/N), baseline correction, multiplicative scatter correction were used for promotion of predicting performance The result showed that the progress of (log-BC-MSC) in turn achieved optimal calibration of MIR spectra and better prediction for ex-situ soils Though the calibration data were treated by different pre-treating schema, the R2 of the 8 elements followed the same law: Ni > 08 > Cr, Cu, Zn, Pb, Hg > 06 > As, Cd When we applied these calibrations to Baguazhou Island soils, (log-BC-MSC) treated data results in the smallest RMSEp-BGZ We used the same calibration method to compare the predictive ability of MIR spectra to VNIR spectra The R2 of 8 elements developed by VNIR spectral calibration are sometime larger than MIR's, but after we applied these calibrations to validation set, the RSME of MIR data for prediction of BGZ soil samples is 21% to 73% of VNIR's This result showed us that for predicting ex-situ soils, MIR analysis substantially outperformed VNIR These results indicated that MIR spectra can be used to predict soil heavy metal content quickly and non-destructively

True-Color Night Vision (TCNV) Fusion System using a VNIR EMCCD and a LWIR Microbolometer Camera *

Abstract: A fully functional, prototype night vision camera system is described which produces true-color imagery, using a visible/near-infrared (VNIR) color EMCCD camera, fused with the output from a thermal long-wave infrared (LWIR) microbolometer camera. The fusion is performed in a manner that displays the complimentary information from both sources without destroying the true-color information. The system can run in true-color mode in day-light down to about 1/4-moon conditions, below this light level the system can function in a monochrome VNIR/LWIR fusion mode. An embedded processor is used to perform the fusion in real-time at 30 frames/second and produces both digital and analog color video outputs. The system can accommodate a variety of modifications to meet specific user needs, and various additional fusion algorithms can be incorporated making the system a test-bed for real time fusion technology under a variety of conditions.

ASTER VNIR and SWIR Radiometric Calibration and Atmospheric Correction

Abstract: As described in the previous chapter, ASTER relies on three separate subsystems to cover the full spectral range from the visible and near infrared (VNIR), short-wave infrared (SWIR), to the thermal infrared (TIR). Establishing the accuracy of data from all three subsystems requires both sensor-related calibration and atmospheric correction. The dominance of reflected solar energy in the VNIR and SWIR, and emitted terrestrial radiation in the TIR allows separate treatment of the two spectral regions. TIR calibration and correction are covered in a separate chapter. This chapter has two main goals: (1) to allow the user to understand ASTER’s radiometric calibration and atmospheric correction processes that enable conversion of VNIR and SWIR digital numbers (DN) to at-sensor reflectance and spectral radiance, and (2) to provide a succinct analysis of the SWIR crosstalk problem and its solutions.

Issues Affecting Geological Mapping with ASTER Data: A Case Study of the Mt Fitton Area, South Australia

Abstract: The minerals industry uses multispectral Advanced Spaceborne Thermal Emission Reflectance Radiometer (ASTER) data for geological mapping with enthusiasm around the world. ASTER represents an advance beyond the capabilities of the 7-band Landsat Thematic Mapper, measuring radiant energy from 14 bands, within the visible-near infrared (VNIR), the shortwave infrared (SWIR), and thermal infrared (TIR) wavelength regions, at spatial resolutions ranging from 15 to 90 m (Yamaguchi et al. 1998). Geologists used ASTER data for its multispectral coverage in the mineralogically significant SWIR wavelength region (Yamaguchi et al. 1998), where OH-bearing and carbonate minerals have diagnostic spectral features (Clark et al. 1990; Grove et al.1992). ASTER also provides multispectral coverage within TIR wavelengths (Yamaguchi et al. 1998), where many other silicates (and carbonates) have diagnostic features (Salisbury and D’Aria 1992).

Hyperspectral reflectance of boreo-nemoral forests in a dry and normal summer

Abstract: The visible-near infrared (VNIR) reflectance of several mature boreo-nemoral stands in Estonia was measured in two concurrent years which differed significantly in precipitation. Custom-designed VNIR spectrometer systems, UAVSpec and UAVSpec2, mounted onboard a helicopter, were used for the measurements. We show that broadleaved and coniferous forests react to changes in water supply differently: the relative change of the NIR reflectance was equally about 10-15% in all stands, while the change of visible reflectance of coniferous stands exceeded that of broadleaved stands. The smallest change was observed for broadleaved stands in the red reflectance, i.e. chlorophyll absorption bands. Based on our results, we conclude that the change of stand reflectance caused by weather conditions, such as drought, should be taken into account in the estimation of the optical properties of the atmosphere, needed in the atmospheric correction of optical satellite images. A widely used correction method directly benefiting from our results for boreo-nemoral forests is the dark object method.

Onboard spectral calibration for the Japanese hyper-spectral sensor

Abstract: The Japanese hyper-spectral sensor provides data products covering continuous spectral bands in the wavelength range from 400 nm to 2500 nm. It is characterized by a SNR of > 450 in the VNIR and>300 in the SWIR range at a ground resolution of 30 m x30 m. This report is concerned with the onboard wavelength calibration methods for the Japanese hyper-spectral sensor. As a result of trade study, the combination of a transmission type glass filter containing rare earth oxides, a Mylar polyester film and a quartz tungsten-halogen-lamp was selected. This method covers the wavelength range from 400 nm to 2450 nm. For the purpose of wavelength shift estimation, the method employing the mean square deviation as merit-function was found to be stable and precise. The accuracy of the absorption peak wavelength determination will be expected less than 2% (=0.2 nm) for the VNIR spectral resolution and 5% (=0.625 nm) for the SWIR spectral resolution.

The functional evaluation model for the on-board hyperspectral radiometer

Abstract: The hyper-multi spectral mission named HISUI (Hyper-spectral Imager SUIte) is the next Japanese earth observation project that will be on board ALOS-3 satellite. This project is the follow up mission of the Advanced Spaceborne Thermal Emission and reflection Radiometer (ASTER). HISUI is composed of hyperspectral radiometer with higher spectral resolution and multi-spectral radiometer with higher spatial resolution. The functional evaluation model is under development to confirm the spectral and radiometric performance prior to the flight model manufacture phase. This model contains the VNIR and SWIR spectrograph, the VNIR and SWIR detector assemblies with a mechanical cooler for SWIR, signal processing circuit and on-board calibration source.

Tuz Gölü: New CEOS reference standard test site for infrared visible optical sensors

Abstract: Tuz Golu, a dry salt lake located in the central plateau of Anatolia (38.50°N, 33.20°E, center latitude longitude) in Turkey, was established as a standard reference test site for the vicarious calibration of land surface imagers. The site was first selected on the basis of the spatial uniformity results from the analysis of Moderate Resolution Imaging Spectroradiometer (MODIS) images from July–August 2004 and July–August 2006. This proved its suitability for the calibration of high- and medium-resolution optical sensors. During the 2008 and 2009 measurement campaigns, the site was characterized in terms of its solar spectral surface reflectance factor (RF) and surface bidirectional reflectance factor (BRF) characteristics and atmospheric conditions. The average surface reflectance factor is between 0.4 and 0.6 in the visible and near infrared (VNIR) and about 0.2 in the short-wave infrared (SWIR), which makes this site suitable mainly for the VNIR spectral region. The site is spatially uniform to within ...

Early Mars Environments Revealed Through Near-Infrared Spectroscopy of Alteration Minerals

Abstract: While unstable on present-day Mars, liquid water was an important geologic agent in Mars' past. This work investigates the nature and timing of aqueous processes on ancient Mars, focusing on the earliest epoch of Mars history, the Noachian (>3.7 Gyr), and strata bearing alteration minerals. This work seeks: (1) a refined understanding of what is knowable about past aqueous conditions based on remote visible/near-infrared (VNIR) analyses of altered surfaces; (2) a greater understanding of the changing habitability potential of Mars through time and, more broadly, (3) an increased understanding of aqueous environments during the first billion years of the evolution of a terrestrial planet. Orbital data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) VNIR imaging spectrometer were used to identify key minerals and characteristic mineral assemblages, including hydrated silicates and carbonates. Coupling mineral identifications with high resolution morphology to assess stratigraphic relationships allows constraining past environmental conditions. The findings herein point to temporally and spatially variable settings of aqueous alteration on ancient Mars, including lacustrine, near-surface leaching, and subsurface hydrothermal environments. This diversity indicates multiple potentially habitable environments early in Mars history. Terrestrial field and laboratory investigations of mineralogic determinations derived from VNIR spectroscopy versus other techniques show that (1) infrared spectroscopy correctly characterizes the mineralogy of rocks from Mars-analogue weathering and hydrothermal systems in Iceland and (2) quantitative abundances for simple mixtures of smectite clays with mafic minerals can be successfully estimated with Hapke and Shkuratov radiative transfer models in well-controlled laboratory settings. Presently employed VNIR quantitative analyses techniques are, however, challenged by multi-component mixtures with complex textures or multiple grain sizes. Qualitative remote VNIR mineralogic analyses can be used synergistically with ground-based analytical techniques such as microscopic imaging, x-ray diffraction and geochemical analyses to elucidate further details of alteration mineral formation conditions. The multiple environments of aqueous alteration revealed through VNIR study of Mars' ancient rocks represent key targets for future exploration.

Research on nitrogen content of leaf of Jincheng orange cultivar using visible near infrared spectroscopy model

Abstract: Visible/near-infrared spectroscopy (Vis/NIRS) appears as a prominent technique for non-destructive evaluation In this research,the potential of using the Vis/NIRS was investigated for measuring the nitrogen content in Peng'an 100 Jincheng orange leaves,and the relationship was established between non-destructive VNIRS measurement and the nitrogen content in Peng'an 100 Jincheng orange leaves Intact Peng'an 100 Jincheng orange leaves were measured by reflectance VNIR in 350 to 1000 nm range The data set as the reflectance VNIR was analyzed in order to build the best prediction model for these characteristic,using several spectral pretreatments such as First Derivatives Spectrum (FDS),Second Derivatives Spectrum (SDS) and Reciprocal Logarithm Spectrum [Log (1/R)] with Standardization of Variables (SNV) techniques The results showed the reflectance spectrums of leaves presented downward trend within 350 to 700 nm and upward trend within 750 to 1000 nm with the increasing of the nitrogen fertilizer in potted plant of Peng'an 100 Jincheng orange (Citrus sinensis Osbeck) on trifoliate (Poncirous trifoliata) rootstock The model for the nitrogen content in Peng'an 100 Jincheng orange leaves prediction using FDS with SNV spectral pretreatments showed an excellent prediction performance This non-destruc-tive,fast and accurate technology can be used in citrus industry that would be beneficial to predict the plant nutrition

VNIR image simulation based on low-level flight image data

Abstract: A simulation method for visible and near infrared (VNIR) image is mentioned. The VNIR image obtained by low-level flight is adopted as data resource. After atmospheric correction, the ground reflectivity can be deducted. The simulation method consists of four steps: radiative transfer, spatial resolution, modulation transfer function, and noise simulation. The image of satellite-borne or high-level air-borne sensor could be generated by the simulation method from VNIR image. Experiment is carried out to test the method using an airship as platform. The resulting simulated image is compared to the image with quickbird panchromatic band. The result shows that simulation images enables one to effectively reproduce the entire process of remote sensing of the Earth. The method can be used to simulate VNIR image at satellite level at the same area and the same wavelength.

Compact survey and inspection day/night image sensor suite for small unmanned aircraft systems (EyePod)

Abstract: EyePod is a compact survey and inspection day/night imaging sensor suite for small unmanned aircraft systems (UAS). EyePod generates georeferenced image products in real-time from visible near infrared (VNIR) and long wave infrared (LWIR) imaging sensors and was developed under the ONR funded FEATHAR (Fusion, Exploitation, Algorithms, and Targeting for High-Altitude Reconnaissance) program. FEATHAR is being directed and executed by the Naval Research Laboratory (NRL) in conjunction with the Space Dynamics Laboratory (SDL) and FEATHAR's goal is to develop and test new tactical sensor systems specifically designed for small manned and unmanned platforms (payload weight < 50 lbs). The EyePod suite consists of two VNIR/LWIR (day/night) gimbaled sensors that, combined, provide broad area survey and focused inspection capabilities. Each EyePod sensor pairs an HD visible EO sensor with a LWIR bolometric imager providing precision geo-referenced and fully digital EO/IR NITFS output imagery. The LWIR sensor is mounted to a patent-pending jitter-reduction stage to correct for the high-frequency motion typically found on small aircraft and unmanned systems. Details will be presented on both the wide-area and inspection EyePod sensor systems, their modes of operation, and results from recent flight demonstrations.

Characterization of ASTER data for mineral exploration

Abstract: Rapid advances in remote sensing technology and digital image processing techniques created the best opportunities for detailed mapping and understanding of the earth's surface with perspective of mineral exploration. The advanced spaceborne thermal emission and reflection radiometer (ASTER) is one of the recent generations of medium resolution multispectral satellite remote system that are designed and have been reported substantial applications in geologic mapping especially in arid and semi-arid zones. The ASTER sensor has 14 bands and measures reflected radiation in VNIR (3bands between 0.52 0.86μm with spatial resolution 15m), SWIR (6 bands between 1.6 to 2.43μm with spatial resolution 30m) and TIR (5 bands8.125 to 11.65μm with spatial resolution 90m) electromagnetic energies. ASTER swath width is 60km (each scene is 60x60km). These characteristics make it an excellent choice as a space-borne sensor for applications in geology and mineral exploration, where the data are digitally processed for extraction of biophysical and biochemical parameters of the features for inferring scientific information of mineral in the area of interest. In term of digital image processing, extraction of information pertaining to mineral exploration can be categorized in 3 main groups; namely: (i) selection of effective information with reduction of spectral dimension using principal component analysis (PCA) in parametric and discriminant analysis for non-parametric approaches; and (ii) spectral transforms where enhancement of feature of interest are established from the known sites to larger area extend, and (iii) minimizing noise fractions (MNF) in the data for enhancing the feature of interest. This paper will review the digital image processing for mineral exploration for arid and semi-arid zones, taking into account also the opportunities and shortcomings of the current and state of the art of the existing techniques. Emphasis is placed on deriving mineral indicators such as identification of areas of altered rocks, which usually associated with ore deposition such as gold and cooper.

Non-optically combined multispectral source for IR, visible, and laser testing

Abstract: Electro Optical technology continues to advance, incorporating developments in infrared and laser technology into smaller, more tightly-integrated systems that can see and discriminate military targets at ever-increasing distances. New systems incorporate laser illumination and ranging with gated sensors that allow unparalleled vision at a distance. These new capabilities augment existing all-weather performance in the mid-wave infrared (MWIR) and long-wave infrared (LWIR), as well as low light level visible and near infrared (VNIR), giving the user multiple means of looking at targets of interest. There is a need in the test industry to generate imagery in the relevant spectral bands, and to provide temporal stimulus for testing range-gated systems. Santa Barbara Infrared (SBIR) has developed a new means of combining a uniform infrared source with uniform laser and visible sources for electro-optics (EO) testing. The source has been designed to allow laboratory testing of surveillance systems incorporating an infrared imager and a range-gated camera; and for field testing of emerging multi-spectral/fused sensor systems. A description of the source will be presented along with performance data relating to EO testing, including output in pertinent spectral bands, stability and resolution.

Time-Sequential multi-spectrum imaging device

Abstract: The present invention discloses a time-sequential multi-spectrum image acquiring device structure which uses a single camera module to achieve multi-spectrum image acquiring in a time-sequential architecture, thereby providing a simple, lightweight telemetry system and reducing the development and operation costs thereof. For example, a visible and near infrared (VNIR) imaging system reduces the use of four camera modules (each including an optical lens, filter, sensor, and image signal processing unit) to single camera module, the VNIR imaging system acquires multi-spectrum images having the same image geometric parameters for image calibration and can simplify the calibration process. The present invention is implemented by introducing a multi-spectrum filter wheel capable of rotating in high speed in the camera module and controlling the image acquiring frequency of the sensor and the synchronicity of the wheel rotating speed for multi-spectrum image acquiring. The present invention is suitable for use in multi-spectrum images acquiring of airborne telemetry requiring lightweight system, such as multi-spectrum images acquiring of unmanned aerial vehicle (UAV).

Design of compact Offner hyperspectral imaging system with Féry prism

Abstract: In order to decrease the volume and quality of an imaging system and to correct the smile of a spectral image,a novel Offner hyperspectral imaging system with Fery prisms is presented.In this system,a pairs of Fery curved surface prisms are located at two arms of the Offner relay configuration and the light beam passes through the prisms twice to be dispersed.Therefore,the system shows a lighter and smaller structure as compared with conventional one when it gains a given dispersion value.To decrease the nonlinear dispersion of spectral channel in Visible-Near Infrared(VNIR),a couple of anti-dispersion flint Fery prisms are introducted into this system again.Then,two kinds of hyperspectral imaging systems applied to VNIR and Short-Wave Infrared(SWIR)channels are designed,respectively.The analytical results indicate the smiles and keystones of the two spectral imaging systems are less than 0.1 pixel and 0.045 pixel,respectively,and the nonlinearity is less than 0.1,which satisfies the requirements of airborne or spaceborne hyperspectral imagers.

Hydrothermal alteration mapping using aster data in East Kunlun Mountains, China

Abstract: ASTER has higher spatial resolution in the VNIR region and higher spectral resolution in the shortwave infrared (SWIR) region in comparison with ETM+, which provide us an opportunity to distinguish various clay-alteration minerals accurately. In this paper, the 14 bands of ASTER were adopted to identify the lithologic and hydrothermal alteration minerals, such as the calcite, kaolinite and OH bearing minerals and so on, in the East Kunlun region of China. The effect of different mapping methods presented in the past, including band ratio, relative band-depth (RBD) images, False Color Composite (FCC) and SFF et al, were compared and analyzed. Results indicate that the mineral index method is suit to the high and cold mountainous area and could get the ideal result relative to the others. This work study once more again shows that the multi-spectral remote sensing techniques have excellent potentials for metallic mineral prognostication.