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Journal of the Optical Society of America A

Journal of the Optical Society of America A



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Early Posting

Accepted papers to appear in an upcoming issue

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Articles 1 to 20 of 31 Next Page >>


Creation of a 50,000λ long needle-like field with 0.36λ width – reply to comment

  • Qing Cao, Minning Zhu, and Hua Gao
  • received 01/21/2015; accepted 04/24/2015; posted 04/24/2015; Doc. ID 232884
  • [full text: PDF (438) KB)]
  • Abstract: This is the reply to the comment by Chavez-Cerda and Pu [J. Opt. Soc. Am. A ××× (2015)] on our recent work about the 50,000λ long needle-like field [J. Opt. Soc. Am. A 31, 500 (2014)]. First, they employed an incorrect boundary condition as the fundament of their argument. In fact, it is not the electric field but its tangential component that must be zero at the surface of the perfect metal. Our result is completely consistent with the correct boundary condition. Second,an arbitrary constant phase factor in the incident radially polarized beam, exp(jπ/4) for instance, has no influence on the result. Accordingly, our initial condition is proper. Third, for the suggested applications of electron acceleration and of optical trapping of thin and long objects, there is no need of the longitudinal component of the energy flow density.

Keywords (OCIS):

  • (030.1670) Coherence and statistical optics : Coherent optical effects
  • (050.1970) Diffraction and gratings : Diffractive optics
  • (080.2740) Geometric optics : Geometric optical design
  • (220.1770) Optical design and fabrication : Concentrators
  • (230.4040) Optical devices : Mirrors

Derivation of various transfer functions of ideal or aberrated imaging systems from the three-dimensional transfer function

  • Joseph J. M. Braat and A.J.E.M. Janssen
  • received 03/02/2015; accepted 04/24/2015; posted 04/24/2015; Doc. ID 235505
  • [full text: PDF (1807) KB)]
  • Abstract: The three-dimensional frequency transfer function for optical imaging systems has been introduced by Frieden in the 1960's. The analysis of this function and its partly back-transformed functions (two-dimensional and one-dimensional optical transfer functions) in the case of an ideal or aberrated imaging system has received relatively little attention in the literature. Regarding ideal imaging systems with an incoherently illuminated object volume, we present analytic expressions for the classical two-dimensional x-y transfer function in a defocussed plane, for the axial z-transfer function in the presence of defocussing and for the x-z-transfer function in the presence of a lateral shift y of the incoherent line illumination pattern in object space. For an aberrated imaging system we use the common expansion of the aberrated pupil function with the aid of Zernike polynomials. It is shown that the line integral appearing in Frieden's three-dimensional transfer function can be evaluated for aberrated systems using a relationship established first by Cormack between the line integral of a Zernike polynomial over a full chord of the unit disk and a Chebyshev polynomial of the second kind. Some new developments in the theory of Zernike polynomials from the last decade allow us to present explicit expressions for the line integral in the case of a weakly aberrated imaging system. We outline a similar, but more complicated, analytic scheme for the case of severely aberrated systems.

Keywords (OCIS):

  • (080.1010) Geometric optics : Aberrations (global)
  • (110.0110) Imaging systems : Imaging systems
  • (110.4850) Imaging systems : Optical transfer functions
  • (180.6900) Microscopy : Three-dimensional microscopy

Phases of Talbot patterns in angular self-imaging

  • Hugues Guillet de Chatellus, Eric Lacot, Olivier Jacquin, olivier HUGON, Naima Khebbache, and Jose Azana
  • received 02/04/2015; accepted 04/21/2015; posted 04/21/2015; Doc. ID 233989
  • [full text: PDF (1081) KB)]
  • Abstract: The original Talbot (self-imaging) effect is observed in the vicinity of a grating of slits shined with a plane wave, and results in periodic images of the initial diffraction pattern (integer Talbot effect) and the appearance of images with a periodicity reduced by an integer factor (fractional Talbot effect). Most of the studies on Talbot effect so far have focused on the distribution of the intensity of the diffracted light. However the phases of the Talbot images can be calculated in a closed form and display interesting auto-correlation properties. Here we provide what we believe to be the first experimental investigation of the phases of Talbot images. We address the problem of the experimental measurement of the phases of the Talbot images in the equivalent frame of the angular Talbot effect, a recently reported manifestation of the Talbot effect in the far field. The phases of the Talbot images are measured by far field holography and the obtained results suggest the possibility of using the scheme for a precise “fractional ruler” aimed at distances’ measurements. Our results are in excellent agreement with the theoretical calculations.

Keywords (OCIS):

  • (050.1950) Diffraction and gratings : Diffraction gratings
  • (070.6760) Fourier optics and signal processing : Talbot and self-imaging effects

Free space optical communication using beam parameters with translational and transverse rotational invariance

  • Jebathilagar Ivan and Kaumudibikash Goswami
  • received 02/11/2015; accepted 04/15/2015; posted 04/16/2015; Doc. ID 234485
  • [full text: PDF (1358) KB)]
  • Abstract: Two natural requirements on a measurable quantity possessed by a paraxially propagating light- field to be suitable for free space optical communication are : invariance under free space prop- agation, and invariance under transverse plane rotation. While the former invariance ensures that the measurable quantity is robust while signalling through free space, the latter invariance ensures that a detector measuring the quantity can be oriented at any angle in the transverse plane, and a measurement by the detector yields the same value for the quantity irrespective of the transverse angle, thus avoiding alignment issues. The variance matrix of a paraxially prop- agating light-field is analyzed from the perspective of the aforementioned invariances. That the ‘charge’ of a paraxial light-field, which is contained in the variance matrix, and which has been previously well studied for its suitability towards free space optical communication, possesses these two invariance properties, emerges naturally in the analysis. Seven functionally indepen- dent quantities other than charge, which are derived from the variance matrix, and which share these invariances are presented and studied for their suitability towards signalling through tur- bulent atmosphere using the lower order Hermite-Gaussian modes. It is found that the spot size of a Gaussian light-field can be effectively used as a switch, to communicate through short distances in a turbulent atmosphere.

Keywords (OCIS):

  • (030.6600) Coherence and statistical optics : Statistical optics
  • (030.7060) Coherence and statistical optics : Turbulence
  • (070.0070) Fourier optics and signal processing : Fourier optics and signal processing
  • (070.2580) Fourier optics and signal processing : Paraxial wave optics
  • (070.2590) Fourier optics and signal processing : ABCD transforms
  • (070.7345) Fourier optics and signal processing : Wave propagation

Superpositions of asymmetrical Bessel beams

  • Alexey Kovalev, Victor Soifer, and Victor Kotlyar
  • received 01/28/2015; accepted 04/14/2015; posted 04/14/2015; Doc. ID 233336
  • [full text: PDF (2564) KB)]
  • Abstract: We considered nonparaxial asymmetrical Bessel modes of the first and second types, which differ from a conventional symmetrical Bessel mode by a real-valued shift along one Cartesian coordinate and an imaginary shift along another (both shifts are equal in modulus). The first- and second-type Bessel modes differ only in signs of the shift, and therefore have different orbital angular momentum (OAM) (integer or fractional). Addition and subtraction of complex amplitudes of two identical asymmetrical Bessel modes of the first and second type leads to light beams with the same integer OAM equal to the topological charge n of the original mode, but with different transverse intensity distributions, which depend on the shift magnitude. It allows controlling the OAM of the beam with simultaneous changing its shape, i.e. for matching with the object being trapped.

Keywords (OCIS):

  • (050.1960) Diffraction and gratings : Diffraction theory
  • (350.5500) Other areas of optics : Propagation
  • (050.4865) Diffraction and gratings : Optical vortices

Evaluation criterion of thermal light ghost imaging based on the receiver operating characteristic analysis

  • Wen-Kai Yu, Xu-Ri Yao, Xue-Feng Liu, Long-Zhen Li, and Guang-Jie Zhai
  • received 12/24/2014; accepted 04/13/2015; posted 04/14/2015; Doc. ID 231405
  • [full text: PDF (3135) KB)]
  • Abstract: We compare the performances of different thermal ghost imaging (GI) algorithms in an experiment of computational GI using a digital micromirror device. Instead of applying traditional image quality evaluation methods like the peak signal-to-noise ratio, the mean square error or the contrast-to-noise ratio, here we present a rather different evaluation criterion named receiver operating characteristic (ROC) analysis served as the performance of merit for the quantitative comparison. A ROC curve is created by plotting the true positive rate against the false positive rate at various threshold settings. Both theoretical analysis and experimental results demonstrate that the ROC curve and the area under the curve are better and more intuitive indicators of the performance of the GI, compared with conventional evaluation methods. Our scheme should attract general interest and open exciting prospects for ROC analysis in thermal GI.

Keywords (OCIS):

  • (000.5490) General : Probability theory, stochastic processes, and statistics
  • (110.1650) Imaging systems : Coherence imaging
  • (110.3000) Imaging systems : Image quality assessment
  • (120.4800) Instrumentation, measurement, and metrology : Optical standards and testing
  • (110.3010) Imaging systems : Image reconstruction techniques

Estimation of Bispectral Donaldson Matrices of Fluorescent Objects by Using Two Illuminant Projections

  • Shoji Tominaga, Keita Hirai, and Takahiko Horiuchi
  • received 12/26/2014; accepted 04/13/2015; posted 04/14/2015; Doc. ID 231492
  • [full text: PDF (1348) KB)]
  • Abstract: This paper proposes a method for estimating the bispectral Donaldson matrices of fluorescent objects by using only two illuminant projections with continuous spectral-power distributions. The Donaldson matrix represents the spectral radiance factor consisting of the sum of two components: a reflected radiance factor and a luminescent radiance factor. First, we describe the spectral characteristics of the observed matrix and model the matrix so that the luminescent radiance factor is separable into the emission and excitation wavelength components. We make no assumption to the spectral shapes of any components, but derive a physical model that is useful for predicting the excitation spectral component from the diffuse reflection component. An algorithm is developed to estimate the entire elements of the Donaldson matrix based on only two sets of spectral sensor outputs under two different illuminants. We suggest that the difference between the observed reflectances under the two different illuminants is not caused by the reflected radiance component, but only the luminescent radiance component. The algorithm is a sequential estimation of three radiance components of luminescent excitation, luminescent emission, and reflection. The feasibility of the proposed method is confirmed in experiments using a variety of fluorescent samples. The estimation accuracy is evaluated numerically in RMSE and the CIELAB color difference under the assumption of a viewing illuminant. An optimal selection of the illuminant pair is shown based on a simulation experiment using blackbody radiators with different color temperatures.

Keywords (OCIS):

  • (110.0110) Imaging systems : Imaging systems
  • (330.1710) Vision, color, and visual optics : Color, measurement
  • (110.4234) Imaging systems : Multispectral and hyperspectral imaging

Angular scattering of light by a homogeneous spherical particle in a zeroth-order Bessel beam and its relationship to plane wave scattering

  • Thomas Preston and Jonathan Reid
  • received 01/26/2015; accepted 04/12/2015; posted 04/14/2015; Doc. ID 233243
  • [full text: PDF (1930) KB)]
  • Abstract: The angular scattering of light from a homogeneous spherical particle in a zeroth-order Bessel beam is calculated using generalized Lorenz-Mie theory. We investigate the dependence of the angular scattering on the semi-apex angle of the Bessel beam and discuss the major features of the resulting scattering plots. We also compare Bessel beam scattering to plane wave scattering and provide criterion for when the difference between the two cases can be considered negligible. Finally, we discuss a method for characterizing spherical particles using angular light scattering. This work is useful to researchers who are interested in characterizing particles trapped in optical beams using angular dependent light scattering measurements.

Keywords (OCIS):

  • (010.1110) Atmospheric and oceanic optics : Aerosols
  • (290.3030) Scattering : Index measurements
  • (290.4020) Scattering : Mie theory
  • (290.5820) Scattering : Scattering measurements
  • (290.5850) Scattering : Scattering, particles

Electromagnetic scattering and absorption by randomly oriented Fibers

  • sharhabeel alyones and Charles Bruce
  • received 03/02/2015; accepted 04/12/2015; posted 04/15/2015; Doc. ID 235346
  • [full text: PDF (537) KB)]
  • Abstract: In this article, we numerically calculate the extinction, scattering, absorption and radar cross sections for a randomly oriented finite conducting fiber. Calculations in the long (centimeter wavelengths) and short (infrared wavelengths) are presented and compared with the fixed orientation value when the incident electric field is aligned along the fiber length. The calculations presented in this article are necessary for the parametrization of fibers to play the role of an efficient obscurants and anti-radio frequency interference.

Keywords (OCIS):

  • (290.5850) Scattering : Scattering, particles
  • (290.5825) Scattering : Scattering theory

Performance analysis of compressive ghost imaging based on different signal reconstruction techniques

  • Yan Kang, Yinping Yao, Zhihua Kang, Lin Ma, and Zhang Tong-Yi
  • received 02/04/2015; accepted 04/10/2015; posted 04/14/2015; Doc. ID 233927
  • [full text: PDF (350) KB)]
  • Abstract: We present different signal reconstruction techniques for implementation of compressive ghost imaging (CGI). The different techniques are validated on the data collected from ghost imaging(GI) with pseudothermal light experimental system. Experiment results show that, technique based on total variance (TV) minimization gives high-quality reconstruction of the imaging object with less time consumption. The different performance among these reconstruction techniques and their parameter setting are also analyzed. The conclusion thus offers valuable information to promote the implementation of CGI in real applications.

Keywords (OCIS):

  • (030.0030) Coherence and statistical optics : Coherence and statistical optics
  • (100.3010) Image processing : Image reconstruction techniques
  • (110.2990) Imaging systems : Image formation theory

Spectra restoration of a transmissive periodic structure in near-field diffraction

  • Pin Han
  • received 11/13/2014; accepted 04/10/2015; posted 04/14/2015; Doc. ID 226810
  • [full text: PDF (431) KB)]
  • Abstract: The free space near-field diffraction of a transmissive periodic structure is studied with Fresnel-Kirchhoff diffraction formula. A new effect is proposed theoretically from the results, showing that under some conditions the spectra of an incident coherent polychromatic light can be completely restored after the diffraction. It can be contrasted with its monochromatic counterpart, Talbot images, which rebuild the images of a periodic structure at specific places in the near-field. Taking a sinusoidal amplitude grating as an example for illustrating the idea, the general conditions and specific locations to find the restored spectra are obtained. The spectral switches involved are also presented.

Keywords (OCIS):

  • (050.0050) Diffraction and gratings : Diffraction and gratings
  • (050.1940) Diffraction and gratings : Diffraction
  • (050.1970) Diffraction and gratings : Diffractive optics

Mimicking photon propagation through 2-D waveguide array by a 1-D waveguide array

  • Surajit Paul and Krishna Thyagarajan
  • received 02/04/2015; accepted 04/08/2015; posted 04/10/2015; Doc. ID 233868
  • [full text: PDF (860) KB)]
  • Abstract: Photon propagation through 1-D and 2-D waveguide arrays has been explored for various applications in the field of quantum optics and quantum information. In this paper we show that an appropriately designed one dimensional waveguide array can mimic the photon propagation through a two dimensional array. This alternative design is enticing since fabrication of one dimensional array is relatively less burdensome than two dimensional arrays.

Keywords (OCIS):

  • (130.2790) Integrated optics : Guided waves
  • (130.3120) Integrated optics : Integrated optics devices
  • (270.0270) Quantum optics : Quantum optics
  • (270.5585) Quantum optics : Quantum information and processing

Transformation of vector beams with radial and azimuthal polarizations in biaxial crystals

  • Alex Turpin, Asticio Vargas, Angel Lizana, F. A. Torres-Ruiz, Irene Estévez, Ignacio Moreno, Juan Campos, and Jordi Mompart
  • received 03/04/2015; accepted 04/08/2015; posted 04/10/2015; Doc. ID 235588
  • [full text: PDF (1948) KB)]
  • Abstract: We present both experimentally and theoretically the transformation of radially and azimuthally polarized vector beams when they propagate through a biaxial crystal and are transformed by the conical refraction phenomenon. We show that, at the focal plane, the transverse pattern is formed by a ring-like light structure with an azimuthal node, being this node found at diametrically opposite points of the ring for radial/azimuthal polarizations. We also prove that the state of polarization of the transformed beams is conical refraction-like, i.e. that every two diametrically opposite points of the light ring are linearly orthogonally polarized.

Keywords (OCIS):

  • (260.1180) Physical optics : Crystal optics
  • (260.1440) Physical optics : Birefringence
  • (260.5430) Physical optics : Polarization

Compositional prior information in computed infrared spectroscopic imaging

  • P. Scott Carney, Bradley Deutsch, Rohit Bhargava, David Mayerich, and Rohith Reddy
  • received 02/04/2015; accepted 04/07/2015; posted 04/21/2015; Doc. ID 231676
  • [full text: PDF (1208) KB)]
  • Abstract: Compositional prior information is used to bridge a gap in the theory between optical coherence tomography (OCT), which provides high-resolution structural images by neglecting spectral variation, and imaging spectroscopy, which provides only spectral information without significant regard to structure. A constraint is proposed in which it is assumed that a sample is composed of N distinct materials with known spectra, allowing both the structural and spectral composition of the sample to be determined with a number of measurements on the order of N. We present a forward model for a sample with heterogeneities along the optical axis, and show through simulation that the N-species constraint allows unambiguous inversion of FT interferometric data within the spatial frequency passband of the optical system. We then explore the stability and limitations of this model and extend it to a general 3-d heterogeneous sample.

Keywords (OCIS):

  • (100.0100) Image processing : Image processing
  • (110.0180) Imaging systems : Microscopy
  • (170.3880) Medical optics and biotechnology : Medical and biological imaging
  • (300.0300) Spectroscopy : Spectroscopy

Polarization Properties of A Broadband Multi-Moded Concentrator

  • Alan Kogut, Dale Fixsen, and Robert Hill
  • received 09/15/2014; accepted 04/07/2015; posted 04/10/2015; Doc. ID 223091
  • [full text: PDF (1584) KB)]
  • Abstract: We present the design and performance of a non-imaging concentrator for use in broad-band polarimetry at millimeter through submillimeter wavelengths. A rectangular geometry preserves the input polarization state as the concentrator couples f/2 incident optics to a 2 pi sr detector. Measurements of the co-polar and cross-polar beams in both the few-mode and highly over-moded limits agree with a simple model based on mode truncation. The measured co-polar beam pattern is nearly independent of frequency in both linear polarizations. The cross-polar beam pattern is dominated by a uniform term corresponding to polarization efficiency 94%. After correcting for efficiency, the remaining cross-polar response is -18 dB.

Keywords (OCIS):

  • (030.4070) Coherence and statistical optics : Modes
  • (220.1770) Optical design and fabrication : Concentrators
  • (260.5430) Physical optics : Polarization
  • (350.1260) Other areas of optics : Astronomical optics
  • (040.2235) Detectors : Far infrared or terahertz
  • (080.4298) Geometric optics : Nonimaging optics

Optical sharper focusing in an anisotropic crystal

  • Xiangsheng Xie, SICONG WANG, Min Gu, and Jianying Zhou
  • received 01/21/2015; accepted 04/06/2015; posted 04/10/2015; Doc. ID 233060
  • [full text: PDF (3218) KB)]
  • Abstract: Optical super-resolution technique through tight focusing is a widely used technique to image the material samples with anisotropic optical properties. The knowledge of the field distribution of a tightly focused beam in anisotropic media is both scientifically interesting and technologically important. In this paper, optical properties of a uniaxial crystal with the optic axis perpendicular to the interface under the tight focusing configuration are studied with rigorous theoretical and numerical analysis. The significant effect of the Poynting vector on the focal position introduces an obvious displacement of the focal spot formed by the extraordinary waves (e-ray). Moreover, a sharper focus with a lateral size of 0.22λ is obtained as a result of the effective separation of the ordinary waves (o-ray) and the e-ray. It provides a new tool to fabricate optical structures with a higher resolution than that in an isotropic medium through the far-field method.

Keywords (OCIS):

  • (260.1440) Physical optics : Birefringence
  • (260.1960) Physical optics : Diffraction theory
  • (260.5430) Physical optics : Polarization

General scale-dependent anisotropic turbulence and its impact on free space optical communication system performance

  • Italo Toselli and Olga Korotkova
  • received 11/26/2014; accepted 04/04/2015; posted 04/10/2015; Doc. ID 228589
  • [full text: PDF (648) KB)]
  • Abstract: We generalize a recently introduced model for non-classic turbulent spatial power spectrum involving anisotropy along two mutually orthogonal axes transverse to the direction of beam propagation, by including two scale-dependent weighting factors for these directions. Such turbulent model may be pertinent to atmospheric fluctuations in the refractive index in stratified regions well above the boundary layer and employed for air-air communication channels. On restricting ourselves to unpolarized, coherent Gaussian beam and weak turbulent regime we examine the effects of such turbulence type on the OOK FSO link performance by including the results on scintillation flux, probability of fade, SNR and BERs.

Keywords (OCIS):

  • (010.1290) Atmospheric and oceanic optics : Atmospheric optics
  • (010.1300) Atmospheric and oceanic optics : Atmospheric propagation
  • (010.1330) Atmospheric and oceanic optics : Atmospheric turbulence

A Plenoptic Sensor can determine the Phase and Amplitude Distortion of a Wavefront

  • Chensheng Wu, Christopher Davis, and Jonathan Ko
  • received 12/10/2014; accepted 04/02/2015; posted 04/02/2015; Doc. ID 228962
  • [full text: PDF (2487) KB)]
  • Abstract: We have designed a plenoptic sensor to retrieve phase and amplitude changes resulting from a laser beam’s propagation through atmospheric turbulence. Compared with the commonly restricted domain of (–π, π) in phase reconstruction by interferometers, the reconstructed phase obtained by the plenoptic sensors can be continuous up to a multiple of 2π. When compared with conventional Shack-Hartmann sensors, ambiguities caused by interference or low intensity, such as branch points and branch cuts, are less likely to happen and can be adaptively avoided by our reconstruction algorithm. In the design of our plenoptic sensor, we modified the fundamental structure of a light field camera into a mini Keplerian telescope array by accurately cascading the back focal plane of its object lens with a microlens array’s front focal plane and matching the numerical aperture of both components. Unlike light field cameras designed for incoherent imaging purposes, our plenoptic sensor operates on the complex amplitude of the incident beam and distributes it into a matrix of images that are simpler and less subject to interference than a global image of the beam. Then, with the proposed reconstruction algorithms, the plenoptic sensor is able to reconstruct the wavefront and a phase screen at an appropriate depth in the field that causes the equivalent distortion on the beam. The reconstructed results can be used to guide adaptive optics systems in directing beam propagation through atmospheric turbulence. In this paper we will show the theoretical analysis and experimental results obtained with the plenoptic sensor and its reconstruction algorithms.

Keywords (OCIS):

  • (010.1080) Atmospheric and oceanic optics : Active or adaptive optics
  • (010.1300) Atmospheric and oceanic optics : Atmospheric propagation
  • (010.1330) Atmospheric and oceanic optics : Atmospheric turbulence
  • (010.7350) Atmospheric and oceanic optics : Wave-front sensing
  • (100.3010) Image processing : Image reconstruction techniques


Isotropic inverse-problem approach for two-dimensional phase unwrapping

  • Ulugbek Kamilov, Ioannis Papadopoulos, Morteza H. Shoreh, Demetri Psaltis, and Michael Unser
  • received 01/16/2015; accepted 03/31/2015; posted 04/10/2015; Doc. ID 232692
  • [full text: PDF (3352) KB)]
  • Abstract: In this paper, we propose a new technique for two-dimensional phase unwrapping. The unwrapped phase is found as the solution of an inverse problem that consists in the minimization of an energy functional. The latter includes a weighted data-fidelity term that favors sparsity in the error between the true and wrapped phase differences, as well as a regularizer based on higher-order total-variation. One desirable feature of our method is its rotation invariance, which allows it to unwrap a much larger class of images compared to the state of the art. We demonstrate the effectiveness of our method through several experiments on simulated and real data obtained through the tomographic phase microscope. The proposed method can enhance the applicability and outreach of techniques that rely on quantitative phase evaluation.

Keywords (OCIS):

  • (100.3010) Image processing : Image reconstruction techniques
  • (100.3190) Image processing : Inverse problems
  • (100.3175) Image processing : Interferometric imaging
  • (100.5088) Image processing : Phase unwrapping

Hemispherical Reflectance Model For Passive Images In Outdoor Environment

  • Charles Kim, Bea Thai, Neil Yamaoka, and Omar Aboutalib
  • received 02/06/2015; accepted 03/30/2015; posted 03/31/2015; Doc. ID 234158
  • [full text: PDF (590) KB)]
  • Abstract: We present a hemispherical reflectance model for simulating passive images in outdoor environment where illumination is provided by natural sources such as the sun and the clouds. While bi-directional reflectance distribution function (BRDF) accurately produces radiance from any objects after the illumination, using the BRDF in calculating radiance requires double integration. Approximating the BRDF by hemispherical reflectance under the natural sources transforms the double integration into a multiplication. This reduces both storage space and computation time. We present the formalism for the radiance of the scene using hemispherical reflectance instead of BRDF. It enables us to generate passive images in outdoor environment taking advantage of the computational and storage efficiencies. We show some examples for illustration

Keywords (OCIS):

  • (110.0110) Imaging systems : Imaging systems
  • (290.5880) Scattering : Scattering, rough surfaces
  • (290.1483) Scattering : BSDF, BRDF, and BTDF
  • (110.1758) Imaging systems : Computational imaging
  • (280.4991) Remote sensing and sensors : Passive remote sensing
  • (290.6815) Scattering : Thermal emission

Articles 1 to 20 of 31 Next Page >>

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