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A new scheme focusing on modification and control of distortion in the reflection and transmission of Goos-Hanchen (GH) shifted beams, is discussed. The absorptivity, reflectivity, and transmissivity are measured for the new atomic scheme. The GH-shifted beam is modified by control fields and incident angle. The sum of absorption, transmission, and reflection coefficients is equal to one. For positive reflection GH-shift region, there is negative transmission GH shift. The distortion in the reflected and transmitted beam is controlled with incident angle and control fields. The results discussed in this article show significant applications in micro-optics and nano-optics, acoustics, and plasma physics. Nous discutons dans cet article un nouveau schema qui se focalise sur la modification et le controle de la distorsion dans la reflexion et la transmission d'un faisceau sous decalage de Goos-Hanchen. Nous mesurons l'absorptivite, la reflectivite et la transmissivite dans ce nouveau schema atomique. Le faisceau a decalage GH est modifie par des champs de controle et l'angle d'incidence. La somme des coefficients d'absorption, de transmission et de reflexion est egale a un. Pour la region GH decalee de reflexion positive, il y a une region GH decalee de transmission negative. La distorsion dans les faisceaux reflechi et transmis est controlee par l'angle d'incidence et champs de controle. Les resultats presentes ici montrent des applications interessantes en micro-optique/nano-optique, acoustique et physique du plasma. [Traduit par la Redaction] Mots-cles: optique quantique, decalage de Goos-Hanchen, distorsion des faisceaux, champ de controle., 1. Introduction The light pulse is used for data communication in the telecom industry. Distortion reduces the information contents of a stream of pulses. Noise-free communication of data is possible [...]

The need to reduce energy consumption in buildings has led to the widespread adoption of energy efficient light sources, such as LEDs. Diffused light reflectors are usually preferred to distribute LED illumination uniformly across the room. In this study, unpigmented PMMA films were studied for their diffused reflectance properties. PMMA films were cast onto a cold plate under varied humidity conditions to promote the formation of a porous microstructure via soiid/liquid/liquid phase separation. The relationship between casting conditions, nonsolvent content, microstructure, and diffused reflectance was studied. The diffused reflectance was evaluated using a UV/Vis spectrophotometer with an integration sphere, and the microstructure was evaluated with an SEM. It was found that increasing the nonsolvent concentration either through increased absorption of ambient humidity or by directly incorporating water into the recipe creates pores that efficiently refract visible light. Reflectance in the mid 80% was obtained just by exploiting the difference in refractive index between the PMMA and the air-filled pores. High diffused reflectance has been achieved in PMMA films purely by manipulating the film's microstructure without the use of other expensive polymers or pigments., INTRODUCTION The US Energy Information Administration (EIA) estimated that in 2010, lighting comprised 19% or 700 TWh of total US electricity consumption [1]. Energy savings from improved LED lighting in [...]

The reduction in size and the increase in speed of opto- and magnetoelectronic devices is making the probability of nonequilibrium electron-phonon phenomena greater, leading to increased thermal resistance in these devices. The measurement of electron-phonon coupling in materials in these devices is becoming increasingly important for accurate thermal management. Here femtosecond thermoreflectance is used to measure the electron-phonon coupling factor in thin Ni films of varying thickness grown on Si and glass substrates. The thermoreflectance response is measured at 1.3 and 1.55 eV, yielding drastically different responses due to the Fermi-level transition at 1.3 eV in Ni. The influence of this transition on the thermoreflectance response results in a measurement of the electron-phonon coupling factor that is twice as high as that recorded in previous measurements that were unaffected by the Fermi-level transition. OCIS codes: 120.5700, 160.3380, 240.0310, 260.2160, 260.3060, 310.6860.

This paper aims at demonstrating the possibility of merging data from various medium-resolution spaceborne sensors to produce a consistent time series of surface bidirectional reflectance distribution function (BRDF) and albedo products. The spectral, directional, temporal, and spatial aspects of the multisensor fusion are presented. Emphasis is then given on the spectral normalization for the fusion of Medium Resolution Imaging Spectrometer Instrument (MERIS) data with Moderate Resolution Imaging Spectroradiometer (MODIS) and VEGETATION (VGT) data. Two methods are evaluated: a simple statistical method, which relies on a linear regression using all the available spectral bands, and a more innovative method called the spectral mode method, which is based on the restitution of the surface spectral signature by a combination of universal spectral functions. Analysis with Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) hyperspectral data and satellite products reveals that the spectral mode method is more efficient. This approach is used to merge top-of-canopy bidirectional reflectances from MERIS and VGT for the restitution of BRDF and albedo over a subset of West Africa. Compared to the products obtained with MERIS alone, the fusion with VGT demonstrates an improvement of the spatial coverage and a reduction of product uncertainty by about a third. Index Terms--Albedo, bidirectional reflectance distribution function (BRDF), fusion, Medium Resolution Imaging Spectrometer (MERIS), Moderate Resolution Imaging Spectroradiometer (MODIS), spectral normalization, VEGETATION sensor.

A simple technique to suppress the reflection coefficients [S.sub.11] and [S.sub.22] of surface acoustic wave (SAW) filters is proposed. It is shown by simulation that they can be suppressed to less than -20 dB without deteriorating the transmission characteristics.

A robust statistics-based nonnegative matrix factorization (RNMF) approach is described to recover the measurement in reflectance spectroscopy and it is based on the minimization of a robust cost function and yields two equations updated alternately. The results on the spectral library of reflectance spectra are presented to show the much-improved performance of the RNMF approach.

Three-dimensional appearance models consisting of spatially varying reflectance functions defined on a known shape can be used in analysis-by-synthesis approaches to a number of visual tasks. The construction of these models requires the measurement of reflectance, and the problem of recovering spatially varying reflectance from images of known shape has drawn considerable interest. To date, existing methods rely on either: 1) low-dimensional (e.g., parametric) reflectance models, or 2) large data sets involving thousands of images (or more) per object. Appearance models based on the former have limited accuracy and generality since they require the selection of a specific reflectance model a priori, and while approaches based on the latter may be suitable for certain applications, they are generally too costly and cumbersome to be used for image analysis. We present an alternative approach that seeks to combine the benefits of existing methods by enabling the estimation of a nonparametric spatially varying reflectance function from a small number of images. We frame the problem as scattered-data interpolation in a mixed spatial and angular domain, and we present a theory demonstrating that the angular accuracy of a recovered reflectance function can be increased in exchange for a decrease in its spatial resolution. We also present a practical solution to this interpolation problem using a new representation of reflectance based on radial basis functions. This representation is evaluated experimentally by testing its ability to predict appearance under novel view and lighting conditions. Our results suggest that since reflectance typically varies slowly from point to point over much of an object's surface, we can often obtain a nonparametric reflectance function from a sparse set of images. In fact, in some cases, we can obtain reasonable results in the limiting case of only a single input image. Index Terms--Reflectance, BRDF, image synthesis, image-based rendering, radial basis functions.

We have developed a simple technique to decorrelate remote sensing color band data from depth in optically shallow water. The method linearizes color band data with respect to depth by subtracting an optically deepwater value from the entire waveband under consideration and taking the natural logarithm of the result. Next, this linearized waveband is rotated about the model 2 regression line computed against a bathymetry band. The rotated color band is decorrelated from water depth. We demonstrate the technique for a small area of Kailua Bay, Oahu, HI, using Quickbird multispectral and Scanning Hydrographic Operational Airborne Lidar Survey LIDAR data. Results indicate that color band data are effectively decorrelated from depth, while bottom reflector variability is maintained, thus providing the basis for further analysis of the depth-invariant wavebands. The primary benefit of our technique is that wavebands are rotated independently, preserving relative spectral information. Index Terms--Bathymetry, coastal remote sensing, Kailua Bay, LIDAR, Quickbird, radiative transfer, reflectance.

A method [atmospheric correction via simulated annealing (ACSA)] is proposed that enhances the atmospheric correction of hyperspectral images over dark surfaces. It is based on the minimization of a smoothness criterion to avoid the assumption of linear variations of the reflectance within gas absorption bands. We first show that this commonly used approach generally fails over dark surfaces when the signal to noise ratio strongly declines. In this case, important residual features highly correlated with the shape of gas absorption bands are observed in the estimated surface reflectance. We add a geometrical constraint to deal with this correlation. A simulated annealing approach is used to solve this constrained optimization problem. The parameters involved in the implementation of the algorithm (initial temperature, number of iterations, cooling schedule, and correlation threshold) are automatically determined by using a standard simulated annealing theory, reflectance databases, and sensor characteristics. Applied to a HyMap image with available ground truths, we verify that ACSA adequately recovers ground reflectance over clear land surfaces, and that the added spectral shape constraint does not introduce any spurious feature in the spectrum. The analysis of an AVIRIS image of Central Switzerland clearly shows the ability of the method to perform enhanced water vapor estimations over dark surfaces. Over a lake (reflectance equal to 0.02, low signal to noise ratio equal to about 6), ACSA retrieves unbiased water vapor amounts (2.86 cm [+ or -] 0.36 cm) in agreement with in situ measurements (2.97 cm [+ or -] 0.30 cm). This corresponds to a reduction of the standard deviation by a factor 3 in comparison with standard unconstrained procedures (1.95 cm [+ or -] 1.08 cm). Similar results are obtained using a Hyperion image of DoE ARM SGP test site containing a very dark area of the land surface. Index Terms--Atmospheric correction, dark surfaces, hyperspectral remote sensing, simulated annealing.

The classical Chandrasekhar's formula relating the surface reflectance to the top of the atmosphere radiance rigorously applies to a Lambertian surface. For a homogeneous non-Lambertian surface in a plane-parallel atmosphere, an extension of this formula was proposed in the 1980s and has been recently implemented in the second simulation of the satellite signal in the solar spectrum (6S) algorithm. To analyze this extension, the rigorous formula of the top of the atmosphere signal is derived in a plane-parallel atmosphere bounded by a homogeneous non-Lambertian surface. Then the 6S algorithm extension is compared with the exact formula and approximations and their validity are pointed out. The methods used for the derivation of the exact formula are classical. They are based on the separation of direct and diffuse components of the radiation fields, on the introduction of the Green's function of the problem, and on integrations of boundary values of the radiation fields with the Green's function. OCIS codes: 010.1300, 010.1310, 010.1320, 280.1310, 290.4210.

Radiative properties of thin films are derived based on the concept of optical coherence theory. Instead of the previous approach of deriving the property formulas based on the degree of coherence, a direct integration approach to obtain the averaged properties over a finite spectral resolution is developed. The analytical results are in excellent agreement with the measured spectra. The formulas are compact in form and easy to use to invert optical properties or film thicknesses with measured reflectance or transmittance. Rigorous criteria for incoherent and coherent limits can be easily reduced from the general formulas and the resulting equations corresponding to those of geometric and wave optics, respectively. These criteria are very useful in determining under what situations simpler wave optics and geometric optics formulas can be applied. OCIS codes: 030.1640, 230.4170, 260.3160, 310.0310.

For planar-integrated free-space optical (PIFSO) systems high-reflectance thin-film coatings are crucial. Evaporated metal films are preferred for their relative technological simplicity. We propose a three-layer Al-Ag-Al coating composition that combines the high reflectance of Ag with the chemical passivity of Al and its good adherence to glass. Two special measures are taken to prevent delamination: one is an anchoring of the edges of the coating in narrow ditches that are etched into the substrate and the other is the use of an adhesive Al underlayer; to reduce absorption this underlayer is implemented only in sparsely distributed discrete areas. The optical properties of such composite coatings are investigated theoretically. The fabrication complexity is only slightly increased compared to PIFSO systems with one-layer Al reflectors. In experimental tests we verified a reflectance of approximately 98% and an adherence comparable to that of simple Al coatings. OCIS codes: 310.0310, 310.6860, 050.1970, 350.3950.

Nitride-based flip-chip (FC) light-emitting diodes (LEDs) emitting at 465 nm with Ni transparent ohmic contact layers and Ag reflective mirrors were fabricated. Reliability tests of the LED lamps were also performed by injecting 30-mA dc current into the devices at room temperature.

A novel anisotropic-medium perfectly matched layer (PML) implementation is presented for boundary truncation in the three-dimensional vector finite-element time-domain (FETD) method. This approach utilizes a complex set of vector test and basis functions in the PML region, that recover the usual basis functions in the non-PML region. Numerical examples show that the proposed PML-FETD approach has small reflection errors and no observed late-time instabilities for simulations involving up to [10.sup.6] time steps. Index Terms--Basis functions, finite-element methods, numerical stability, perfectly matched layer, reflection coefficient.

The code SHARM-3D, developed for fast and accurate simulations of the monochromatic radiance at the top of the atmosphere over spatially variable surfaces with Lambertian or anisotropic reflectance, is described. The atmosphere is assumed to be laterally uniform across the image and to consist of two layers with aerosols contained in the bottom layer. The SHARM-3D code performs simultaneous calculations for all specified incidence-view geometries and multiple wavelengths in one run. The numerical efficiency of the current version of code is close to its potential limit and is achieved by means of two innovations. The first is the development of a comprehensive precomputed lookup table of the three-dimensional atmospheric optical transfer function for various atmospheric conditions. The second is the use of a linear kernel model of the land surface bidirectional reflectance factor (BRF) in our algorithm that has led to a fully parameterized solution in terms of the surface BRF parameters. The code is also able to model inland lakes and rivers. The water pixels are described with the Nakajima--Tanaka BRF model of wind-roughened water surface with a Lambertian offset, which is designed to model approximately the reflectance of suspended matter and of a shallow lake or river bottom. OCIS codes: 280.1310, 010.1300.

An inversion procedure for the recovery of absorption coefficients of a two-layered semi-infinite diffusive medium by use of time-resolved reflectance measured at two different source-detector distances is proposed. The inversion procedure is based on the property of the photon diffusion equation; i.e., the solution of the diffusion equation for the time-resolved reflectance measured at a longer source--detector distance coincides with that measured at a shorter one by a proper temporal, spatial, and intensity transformation. This inversion procedure, used together with the results of one set of Monte Carlo simulations, is validated as working well when the values of the scattering coefficients of the two layers and the thickness of the first layer are within a range of interest in tissue optics. of America OCIS codes: 170.3660, 170.5280, 170.4580, 170.7050.

The radiation from a rectangular waveguide with a perfectly conducting infinite flange is rigorously studied by using the method of the Kobayashi potential (KP). The fields in the waveguide and half-space are expanded in terms of the waveguide modes and the Weber-Schafheitlin discontinuous integrals, respectively. Continuity of the tangential aperture fields yields matrix equations for the expansion coefficients and the matrix elements consist of double infinite integrals and double infinite series of Bessel functions, which are calculated efficiently by applying the asymptotic approximation of the Bessel function. Numerical results are presented for various physical quantities, such as the aperture admittance, reflection coefficient of the incident wave, and magnitudes of higher-order mode waves, as well as the far-radiation pattern and aperture fields. To verify the validity of our method, the results are compared with other methods and excellent agreement is obtained. Index Terms--Kobayashi potential (KP), radiation, rectangular waveguide.

An overview of different techniques to characterize liquids in containers and the necessity of introducing a new technique based on the Schoch effect caused by Lamb wave stimulation in the skin of a container is given. It is shown that the Schoch effect can be used to distinguish between different liquids in containers.

A simple numerical approach for the analysis of nonuniform nonlinear distributed feedback (NLDFB) structures. The method was previously proposed for calculating the input-intensity dependence of the reflectivity and transmissivity of a nonlinear dielectric slab for both transverse-electric (TE) and transverse-magnetic (TM) obliquely incident plane elctromagnetic waves.

Operating a meteorological radar is generally a challenging task when in presence of a significant beam blockage as in complex orography. Apart from enhanced ground clutter, mountainous obstructions of the radar beam can significantly reduce the radar visibility and, thus, its monitoring capabilities. Self-consistent adaptive techniques to reconstruct vertical profiles of reflectivity (VPR) and near-surface rain-rate fields from high-elevation reflectivity bins are here proposed, compared, and tested for ranges up to 60 km. The methodology is based on statistical estimators trained by a large reflectivity volumetric datasets, classified into stratiform and convective rain regimes and resampled onto a uniform Cartesian grid by means of a modified Cressman technique. For what concerns reflectivity vertical profiles, two methods, respectively named statistical nonlinear reconstruction (NSR) and neural network reconstruction (NNR), are considered. The NSR method is based on the principal component analysis, applied to the radar dataset, in order to extract significant reflectivity-profile variance. A retrieval technique, based on a nonlinear multiple regression scheme, is then used to infer near-surface reflectivity from available high-altitude echoes at a given range. The NNR is based on a three-layer artificial neural network trained by means a feedforward backpropagation algorithm. For what concerns the near-surface rain retrieval, besides a power-law reflectivity-rain-rate (ZR) approach, a three-layer neural network technique is also set up in order to estimate surface rain rate from reconstructed VPR. The proposed reconstruction techniques are here illustrated by using volumetric data acquired by the C-band Doppler single-polarization radar, operated in L'Aquila, Italy. A case study, related to a rainfall event that occurred during fall 2000, is discussed. Using a test area within 60 km from the radar site and simulating the presence of beam obstructions, a comparison of NSR and NNR with conventional area average reconstruction techniques shows that the percentage improvement of both NSR and NNR approaches is significant, both for the error bias (by 30% to more than 50%, depending on altitude) and variance (by 10% to more than 20%). A sensitivity test indicates that the VPR reconstruction procedure is fairly robust to missing data, especially in terms of error bias. The comparison of estimated radar rainfall with rain gauge data measurement is also illustrated. The mean field bias closer to its optimal value and an error variance much smaller is obtained when neural network techniques are applied than with conventional ZR methods for both techniques of reconstruction. With respect to the latter, the obtained improvement is more than 40% in terms of root mean square error and is comparable when estimating near-surface rain rate using either NSR or NNR methods to reconstruct the reflectivity vertical profiles. Limitations, potential, and future developments of the proposed adaptive reconstruction techniques are finally discussed. Index Terms--Ground-based C-band radar, inversion techniques, radar meteorology, rain field reconstruction, rain-rate retrieval, vertical profile of reflectivity.

A model that relates the coefficients of absorption (a) and backscattering ([b.sub.b]) to diffuse attenuation ([K.sub.d]), radiance reflectance ([R.sub.L]), and the mean cosine for downward irradiance ([[micro].sub.d]) is presented. Radiance transfer simulations are used to verify the physical validity of the model for a wide range of water column conditions. Analysis of these radiance transfer simulations suggests that absorption and backscattering can be estimated with average errors of 1% and 3%, respectively, if the value of [[micro].sub.d] is known with depth. If the input data set is restricted to variables that can be derived from measurements of upward radiance ([L.sub.u]) and downward irradiance ([E.sub.d]), it is necessary to use approximate values of [[micro].sub.d]. Examination of three different approximation schemes for [[micro].sub.d] shows that the average error for estimating a and [b.sub.b] increases to ~13%. We tested the model by using measurements of [L.sub.u] and [E.sub.d] collected from case II waters off the west coast of Scotland. The resulting estimates of a and [b.sub.b] were compared with independent in situ measurements of these parameters. Average errors for the data set were of the order of 10% for both absorption and backscattering. OCIS codes: 010.4450, 290.1350, 300.1030.

A spectral-projected gradient method and an extension of the Kubelka--Munk theory are applied to obtain the relevant parameters of the theory from measured diffuse reflectance spectra of pigmented samples illuminated with visible diffuse radiation. The initial estimate of the spectral dependence of the parameters, required by a recursive spectral-projected gradient method, was obtained by use of direct measurements and up-to-date theoretical estimates. We then tested the consistency of the Kubelka--Munk theory by repeating the procedure with samples of different thicknesses. OCIS codes: 290.3200, 290.4020, 290.4210, 290.5820, 290.7050.

Measurements of the contrast value of time-averaged speckle-modulated images of cartilage tissue are used to study tissue thermal modification in the case of laser-light treatment. This modification is related to thermally induced internal stress relaxation in the matrix of the treated tissue. The specific feature of the evolution of time-averaged speckle contrast with a change in the current temperature of modified collagen tissue is the typical looplike form of the contrast-temperature dependencies associated with irreversible changes in tissue structure and correlated with changes in the tissue diffuse transmittance and the tissue internal stress mentioned by other researchers. OCIS codes: 030.6140, 170.6930.

The most recent theoretical studies have shown that three-dimensional (3-D) radiation effects play an important role in the optical remote sensing of atmospheric aerosol and land surface reflectance. These effects may contribute notably to the error budget of retrievals in a broad range of sensor resolutions, introducing systematic biases in the land surface albedo data sets that emerge from the existing global observation systems. At the same time, 3-D effects are either inadequately addressed or completely ignored in data processing algorithms. Thus there is a need for further development of the radiative transfer theory that can rigorously treat both 3-D and surface anisotropy effects and yet be flexible enough to permit the development of fast forward and inversion algorithms. We describe a new theoretical solution to the 3-D radiative transfer problem with an arbitrary nonhomogeneous non-Lambertian surface. This solution is based on an exact semianalytical solution derived in operator form by the Green's function method. The numerical implementation is based on several parameterizations that accelerate the solution dramatically while keeping its accuracy within several percent under most general conditions.

To numerically calculate bistatic scattering from a fractal rough surface with high permittivity, a comprehensive approach of the forward-backward method (FBM) with spectral accelerate algorithm (SAA) combined with the physics-based two-grid (PBTG) method is developed. Bistatic scattering from and transmitting through one-dimensional (1-D) fractal rough surface with high permittivity, under TE and TM tapered wave incidence, are numerically simulated. Angular reflectivity and transmittivity demonstrate the energy conservation and the functional dependences upon the surface parameters. Index Terms--Bistatic scattering, fractal rough surface, high permittivity, physics-based two-grid (PBTG) forward-backward method (FBM)/ spectral accelerate algorithm (SAA), transmitting.

In this work, we investigate the effects of numerical dispersion in the finite-difference time-domain (FDTD) algorithm for layered, anisotropic media. We first derive numerical dispersion relations for diagonally anisotropic media (corresponding to an FDTD reference frame coinciding with the principal axes of a biaxial media). In addition, we incorporate the discretization effects on the reflection and transmission coefficients in layered media. We then apply this analysis to minimize the numerical dispersion error of Huygens' plane-wave sources in layered, uniaxial media. For usual discretization sizes, a typical reduction of the scattered field error on the order of 30 dB is demonstrated. Index Terms--Buried object detection, finite-difference time-domain (FDTD), numerical analysis.

In this paper we present the results of an analysis of the physically measured surface reflectance spectra of 360 matte Munsell chromatic color chips plus 10 flat achromatic vectors corresponding to Munsell value levels 10 (white) to 1 (near black) for a total sample size of 370. Each of the 370 spectra was multiplied by the spectral radiant power distribution of D65 light so that the final results represent the spectra of reflected light from Munsell color chips under D65 illumination. We simultaneously model the structure of the color chips and the spectra in a common three-dimensional Euclidean space, oriented to yield the most interpretable structure with respect of the Munsell color structure. In this orientation, axis 1 roughly corresponds to the mean power of the spectral reflectance (approximate Munsell value), axis 2 goes from Munsell red to blue-green, and axis 3 goes from Munsell green-yellow to purple. Basis factors for the spectra are also plotted against wavelength and Munsell hue. These plots have implications for theories of opponent processes. By plotting the chips and spectra in the same space we obtain virtually exact correspondences between the various Munsell hues and spectral values in nanometers for comparison to those obtained by previous researchers. Mathematical derivations are provided to validate the common Euclidean model.

Nonlinear estimation method of spectral reflectance from camera responses is proposed. The proposed method minimizes the mean square error of spectral reflectance when the reflectance can be regarded as a random sequence of Gaussian mixture distribution. In computer simulations, 168 samples of spectral reflectance from a color chart are estimated from their image signals obtained by three- and six-band cameras. It is confirmed that the proposed method improves the accuracy in comparison with the conventional Wiener estimation method. OCIS codes: 100.2000, 100.3190, 300.6550, 330.1690.

The normalized difference vegetation index (NDVI) has been widely applied in optical remote sensing. However, it has been demonstrated that NDVI is still partially affected by atmospheric path scattering and bidirectional (illumination and viewing geometry) effects. In this paper we present the benefit of using a bidirectional NDVI, and we discuss the problems in using the maximum NDVI composite method. Based on the assumption that a clear day has a larger NDVI value and a cloudy day has a smaller NDVI value (smaller reflectance in the near-infrared band and larger reflectance in red band due to atmospheric path scattering), the ratio of squared observed NDVI values and calculated NDVI values is used as a weight in our inversion method. The calculated NDVI values are derived from previously inverted bidirectional reflectance distribution functions (BRDFs). The inversion process will loop until all weights converge. Our research on the early Terra/MODIS data using a semiempirical kernel-driven BRDF model (the RossThick-LiTransit model) shows that this new method can improve inversion results whenever some cloudy pixels are not filtered out. As cloud detection and subpixel cloudiness are always a problem, this technique should still be very useful in improving the quality of BRDF inversion. Index Terms--Bidirectional reflectance distribution function, inversion, terra moderate resolution imaging spectroradiometer (MODIS), normalized difference vegetation index (NDVI).

An analytical method has been developed for directly calculating the principal angle [[theta].sub.p] at which the phase difference between the reflection coefficients is equal to 90 [degrees] and at which the ratio of |[r.sub.p]| to |[r.sub.s]| is equal or close to a minimum. The equations given here can be used in many optical applications. For example, ellipsometric data measured at an incidence angle [[theta].sub.p] will have higher precision than data measured at other incidence angles. [[theta].sub.p] is the principal angle. Instead of three principal angles, there is only one principal angle, which can be found in the region of 0 [less than or equal to] [[theta].sub.p] [less than or equal to] 90 [degrees] for most metallic materials used in applications. Results show good agreement between the measured and the calculated spectra of [[DELTA].sub.p] and [[rho].sub.po]. OCIS codes: 260.2130, 260.3910.

We propose a matrix method for the description of light reflection and transmission by an anisotropic multilayer system consisting of thin and thick layers. A method based on partial-wave matrix summations is applicable in the field of reflection and transmission photometry and ellipsometry. In the case of a thin anisotropic film, the interference effects were described by use of a coherent summation of Jones matrices. Incoherent intensity summations for a thick weakly anisotropic layer were characterized by use of the coherency vector formalism. Observable quantities or Mueller matrix components were obtained from the matrix describing transformation of the coherence vectors. OCIS codes: 260.1180, 260.1440, 260.2130, 313.6860, 120.2130.

The measurement of the source reflection coefficient is fundamental for noise, as well as large-signal testing of microwave active devices. This paper describes a simple yet rigorous technique for fast and accurate determination of a source reflection coefficient when a load-source pull test set is used. The solution consists in measuring the waves at the device-under-test reference plane under two different bias conditions. We have proven that these measurements give enough information to compute the source reflection coefficient with accuracy suitable for most applications. Experimental results are presented and compared to data obtained with more conventional techniques. Index Terms--Active device characterization, error box, microwave measurements, network analyzer calibration, source impedance, source--pull, source reflection coefficient.

This article offers a family of strengthenings of Stationary Reflection (SR) as a reflection of multiple stationary sets. This is particularly applied to SR and the Strong Reflection Principle.

A description of the surface plasmon resonance optical technique, its usage, and application in imaging studies is presented. The technique is useful in characterizing lipid bilayer films, monitoring of antibody-antigen interactions occurring at surfaces, DNA hybridization absorption, and protein-DNA interactions.

A pentagon-shaped 0 degree -cut undoped BaTiO(sub 3) crystal was used to construct a high-quality self-pumped phase conjugator. The conjugator shows a steady phase-conjugate output with a high reflectivity (as high as approximately 68%), a fast rising time, and a large angular range of acceptance. It also shows a good fidelity in the phase-conjugate reconstructed image; the resolution reaches 17 (mu)m.

The conventional theory of image transfer through a scattering medium treats objects located upon reflecting surfaces. It is shown that, when an object is located inside a scattering medium and shields a part of space, ignoring the shadowing leads to incorrect results, especially for modern time-gating systems. We develop a general theory of image formation including the shadowing effect when an object is located inside a scattering medium. The example of the observation of a submerged object through a windy ocean surface is chosen to illustrate this theory. A few unexpected effects in imaging of a submerged object are found and discussed, including contrast conversion for a sinking object and higher contrast in the shadow image than in the image of the object itself. The conclusion that using the shadow image for detection of a submerged object can be more efficient than using the image of the object itself is of practical significance.

The conventional definition of emissivity requires the source of radiation to be isothermal in order to compare its thermal emission to that of a blackbody at the same temperature. This requirement is not met for most land surfaces considered in thermal infrared remote sensing. Thus, the effective or equivalent emissivity of nonisothermal surfaces has been a poorly defined but widely used concept for years. Recently, several authors have attempted to define this concept more clearly. Unfortunately, definitions such as ensemble emissivity (e-emissivity) and emissivity derived from the surface bidirectional reflectance distribution function (r-emissivity) [27] do not fully satisfy current needs for estimating true land surface temperature (LST). We suggest the use of an additional term, the 'apparent emissivity increment,' which considers the effects of geometric optics to explain the directional and spectral dependence in LST caused by the three-dimensional (3-D) structure and subpixel temperature distribution of the surface. We define this quantity based upon the emissivity derived from the bidirectional reflectance distribution function (Epsilon-BRDF) for isothermal surfaces and present a conceptual model of thermal emission from nonisothermal land surfaces. Our study also indicates that an average LST corresponding to the hemispherical wideband Epsilon-BRDF will be useful in remote sensing-based LST modeling and inversion. Index Terms: BRDF, brightness temperature, emmisivity, geometric optics, land surface temperature.

This study employs the ray tracing method to analyze and develop mathematical formulae for the internal reflectance of a free standing thick polymer film. The proposed formulae are then used to simulate the diffuse reflectance and diffuse transmittance. Analysis results indicate that internal reflectance is not a constant and varies with film thickness and absorption property. Internal reflectance of the front surface (irradiated surface) surpasses that of the back surface. In addition, all the internal reflectances decrease with the film thickness and the absorption property. In light of the measured thickness and experimentally determined diffuse transmittance of a polymer film, the extinction coefficient to diffuse IR irradiation can be obtained by interpolating in the graphs provided in this study., INTRODUCTION The reflectance (R) and transmittance (T) of a thick free standing film are expressed as follows, respectively (1): [Mathematical Expression Omitted] (1) [Mathematical Expression Omitted] (2) Where [R.sub.e] represents [...]

Light propagation in two-layered turbid media having an infinitely thick second layer is investigated in the steady-state, frequency, and time domains. A solution of the diffusion approximation to the transport equation is derived by employing the extrapolated boundary condition. We compare the reflectance calculated from this solution with that computed with Monte Carlo simulations and show good agreement. To investigate if it is possible to determine the optical coefficients of the two layers and the thickness of the first layer, the solution of the diffusion equation is fitted to reflectance data obtained from both the diffusion equation and the Monte Carlo simulations. Although it is found that it is, in principle, possible to derive the optical coefficients of the two layers and the thickness of the first layer, we concentrate on the determination of the optical coefficients, knowing the thickness of the first layer. In the frequency domain, for example, it is shown that it is sufficient to make relative measurements of the phase and the steady-state reflectance at three distances from the illumination point to obtain useful estimates of the optical coefficients. Measurements of the absolute steady-state spatially resolved reflectance performed on two-layered solid phantoms confirm the theoretical results. OCIS codes: 290.7050, 050.1960, 170.6930.

A combination of finite element formulation and wave function expansion is used to investigate the scattering of axisymmetric guided waves by an interphase region with bonding material between two laminated cylinders. The motivation of this study is to develop an effective numerical technique to characterize the material properties and the thickness of the bond region between two cylinders that are laminated and anisotropic. Numerical results of wave scattering are presented for a welded steel pipe with different weldment shapes and for two cross-ply symmetrically laminated composite cylinders that are bonded end to end. It is shown that as the frequency increases the reflection coefficients have resonance peaks while the transmission coefficients have sharp drops at the cutoff frequencies of higher guided modes in the cylinders. The resonance peaks of reflection coefficients become increasingly pronounced as the thickness of the joint increases. Another interesting feature is that the reflection coefficients have minimums at frequencies that depend on the thickness and the material properties of the joint. These features may be useful in quantitative nondestructive evaluation of joint properties.

By using the concept of transfer matrices and Bloch waves, we have derived a set of equations that provide insight into the operation of asymmetric Bragg reflectors that have been demonstrated to be useful in achieving high reflectivities in strained-material systems. These equations will be useful in the design of asymmetric mirrors and can be used to compare the trade-offs between the conventional, symmetric (quarter-wavelength), and asymmetric mirrors.