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Journal of the Optical Society of America A

Journal of the Optical Society of America A

| OPTICS, IMAGE SCIENCE, AND VISION

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Early Posting

Accepted papers to appear in an upcoming issue

OSA now posts prepublication articles as soon as they are accepted and cleared for production. See the FAQ for additional information.

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October


BRDF Measurements and Analysis of Retroreflective Materials

  • Laurent Belcour, Romain Pacanowski, Marion Delahaie, Aude Laville-Geay, and Laure Eupherte
  • received 08/07/2014; accepted 10/04/2014; posted 10/08/2014; Doc. ID 216686
  • [full text: PDF (1997) KB)]
  • Abstract: We compare performance of various analytical retroreflecting BRDF models to assess how they reproduce accurately measured data of retroreflecting materials. We introduce a new parametrization, the back vector parametrization, to analyze retroreflecting data and we show that this parametrization better preserves the isotropy of data. Furthermore, we update existing BRDF models to improve the representation of retroreflective data.

Keywords (OCIS):

  • (290.5820) Scattering : Scattering measurements
  • (290.1483) Scattering : BSDF, BRDF, and BTDF

Cutoff due to pointwise degradations in color images

  • Alex Golts and Yoav Schechner
  • received 05/19/2014; accepted 10/01/2014; posted 10/03/2014; Doc. ID 210086
  • [full text: PDF (1545) KB)]
  • Abstract: Many studies analyze resolution limits in single channel, pan-chromatic systems. However, color imaging is popular. Thus, there is a need for its modeling in terms of resolving capacity under noise. This work analyzes the probability of resolving details as a function of spatial frequency, in color imaging. The analysis introduces theoretical bounds for performance, using optimal linear filtering and fusion operations. The work focuses on resolution loss caused strictly by noise, without the presence of imaging blur. It applies to full-fifield color systems, which do not compromise resolution by spatial-multiplexing. The presented framework allows to assess and optimize the ability of a color imaging system to distinguish an object of given size and color, under image noise.

Keywords (OCIS):

  • (040.3780) Detectors : Low light level
  • (110.0110) Imaging systems : Imaging systems
  • (110.3000) Imaging systems : Image quality assessment
  • (110.4280) Imaging systems : Noise in imaging systems
  • (350.5730) Other areas of optics : Resolution
  • (010.1690) Atmospheric and oceanic optics : Color

September


Electromagnetic Subsurface Prospecting by a Fully Nonlinear Multi-focusing Inexact Newton Method

  • Marco Salucci, Giacomo Oliveri, Andrea Randazzo, Matteo Pastorino, and Andrea Massa
  • received 09/02/2014; accepted 09/30/2014; posted 10/14/2014; Doc. ID 222079
  • [full text: PDF (417) KB)]
  • Abstract: An electromagnetic inverse scattering procedure for the reconstruction of shallow buried objects in a homogeneous half-space is proposed. The approach is based on the numerical solution of the integral equations modelling the inverse scattering relationships and it extends to strong scatterers the imaging capabilities of previously proposed approach relying on approximated formulations. The inversion is based on the synergic application of a multi-focusing strategy based on the iterative multi-scaling approach (IMSA) along with an efficient regularization scheme based on the inexact-Newton (IN) method. Numerical results corroborate the mathematical description to assess capabilities and current limitations of the proposed fully-nonlinear technique.

Keywords (OCIS):

  • (110.0110) Imaging systems : Imaging systems
  • (280.0280) Remote sensing and sensors : Remote sensing and sensors
  • (290.3200) Scattering : Inverse scattering
  • (110.6955) Imaging systems : Tomographic imaging
  • (110.3010) Imaging systems : Image reconstruction techniques
  • (100.3200) Image processing : Inverse scattering

Effect of beam size, finite number of lines, and rotational misalignment on coupled subwavelength gratings

  • Ange Marie Fievre, Al-Aakhir Rogers, and Shekhar Bhansali
  • received 07/31/2014; accepted 09/29/2014; posted 10/14/2014; Doc. ID 220229
  • [full text: PDF (1165) KB)]
  • Abstract: The effects of beam size, number of lines and rotational misalignment on coupled subwavelength gratings (CSWGs) were investigated in this paper using optical modeling. Period and thickness of the gratings were optimized for maximum evanescent wave coupling efficiency at a wavelength of 650 nm. The size of the input light beam and the number of grating lines was established for discernible transmission of higher diffraction orders, and the half-width-at-half-maximum for minimum noise were determined. A rotation of the far-field pattern, due to milling one grating on a fiber facet, was calculated and confirmed by simulations. These parameters will be included in a method using CSWGs for electronic chips security.

Keywords (OCIS):

  • (050.1950) Diffraction and gratings : Diffraction gratings
  • (050.6624) Diffraction and gratings : Subwavelength structures
  • (070.7345) Fourier optics and signal processing : Wave propagation

(LITH2014) Illumination source optimization in optical lithography via derivative-free optimization

  • Wen Lv, Shiyuan Liu, Xiaofei Wu, and Edmund Lam
  • received 07/07/2014; accepted 09/29/2014; posted 10/03/2014; Doc. ID 216384
  • [full text: PDF (978) KB)]
  • Abstract: Illumination source optimization (SO) in optical lithography is generally performed under a simulated model which does not consider some critical effects, such as vectorial nature of light and mask topography. When the numerical aperture becomes large and the critical dimension reaches the sub-wavelength nodes, the prediction of this model generally fails, and therefore the previous works based on this model become inaccurate. In order to compute SO correctly, we first propose a new source pattern representation method which has moderate parameter variations but remains complete in solution space. Then, we develop a derivative-free optimization (DFO) method to optimize these parameters under a rigorous simulated model. Unlike gradient-based techniques, DFO methods do not require a closed-form formulation of the model and is independent of the form of the cost function.

Keywords (OCIS):

  • (110.5220) Imaging systems : Photolithography
  • (110.1758) Imaging systems : Computational imaging
  • (110.4235) Imaging systems : Nanolithography

A theoretical performance model for single image depth from defocus

  • Pauline Trouvé-Peloux, Frederic Champagnat, Guy Le Besnerais, and Jerôme Idier
  • received 07/25/2014; accepted 09/23/2014; posted 10/08/2014; Doc. ID 217597
  • [full text: PDF (718) KB)]
  • Abstract: In this paper we present a performance model for depth estimation using Single Image Depth From Defocus (SIDFD). Our model is based on an original expression of the Cramér Rao Bound (CRB) in this context. We show that this model is consistent with the expected behavior of SIDFD. We then study the influence on the performance of the optical parameters of a conventional camera such as the focal length, the aperture and the position of the in-focus plane. We derive an approximate analytical expression of the CRB away from the in-focus plane and we propose an interpretation of the SIDFD performance in this domain. Finally, we illustrate the predictive capacity of our performance model on experimental data comparing several settings of a consumer camera.

Keywords (OCIS):

  • (100.3190) Image processing : Inverse problems
  • (150.5670) Machine vision : Range finding
  • (110.1758) Imaging systems : Computational imaging

Holographic laser Doppler imaging of microvascular blood flow

  • C. Magnain, A. Castel, T. Boucneau, M. Simonutti, I. Ferezou, A. Rancillac, T. Vitalis, J. Sahel, M. Paques, and M. Atlan
  • received 09/15/2014; accepted 09/17/2014; posted 10/10/2014; Doc. ID 223162
  • [full text: PDF (1823) KB)]
  • Abstract: We report on local superficial blood flow monitoring in biological tissue from laser Doppler holographic imaging. In time-averaging recording conditions, holography acts as a narrowband bandpass filter, which, combined with a frequency-shifted reference beam, permits frequency-selective imaging in the radiofrequency range. These Doppler images are acquired with an off-axis Mach-Zehnder interferometer. Microvascular hemodynamic components mapping is performed in the cerebral cortex of the mouse and the eye fundus of the rat with near-infrared laser light without any exogenous marker. These measures are performed from basic inverse-method analysis of local first-order optical fluctuation spectra at low radiofrequencies, from 0 Hz to 100 kHz. Local quadratic velocity is derived from Doppler broadenings induced by fluid flows, with elementary diffusing wave spectroscopy formalism in backscattering configuration. We demonstrate quadratic mean velocity assessment in the 0.1-10 mm/s range in vitro, and imaging of superficial blood perfusion with a spatial resolution of about 10 microns in rodent models of cortical and retinal blood flow.

Keywords (OCIS):

  • (040.2840) Detectors : Heterodyne
  • (170.1470) Medical optics and biotechnology : Blood or tissue constituent monitoring
  • (170.3340) Medical optics and biotechnology : Laser Doppler velocimetry
  • (090.1995) Holography : Digital holography

February


(CV) Independence and interaction of luminance and chromatic contributions to spatial hyperacuity performance

  • Bonnie Cooper and Barry Lee
  • received 09/30/2013; accepted 02/02/2014; posted 02/03/2014; Doc. ID 198653
  • [full text: PDF (1336) KB)]
  • Abstract: Here we test interactions of luminance and chromatic input to spatial hyperacuity mechanisms. First, we tested alignment with matching or mismatching (contrast polarity or modality) grating pairs that were adjusted to detection threshold. Thresholds with mismatched pairs were significantly elevated. Second, we determined alignment acuity as a function of luminance or chromatic contrast alone or in the presence of contrast pedestals. For in-phase pedestal conditions, performance followed the envelope of the more sensitive mechanism. However, polarity reversals revealed an asymmetric effect for luminance and chromatic conditions. This suggests that luminance can overrule chromatic mechanisms in hyperacuity; we interpret these findings in the context of spatial mechanisms.

Keywords (OCIS):

  • (330.1720) Vision, color, and visual optics : Color vision
  • (330.5510) Vision, color, and visual optics : Psychophysics
  • (330.6100) Vision, color, and visual optics : Spatial discrimination

Scattering of an electromagnetic plane wave by a homogeneous sphere made of an orthorhombic dielectric-magnetic material: erratum

  • Akhlesh Lakhtakia and Allah Ditta Jafri
  • received 10/27/2014; accepted ; posted 10/27/2014; Doc. ID 225556
  • [full text: PDF (197) KB)]
  • Abstract: A correction is given for an equation in J. Opt. Soc. Am. A {\bf 31}, 89--100 (2014)

Keywords (OCIS):

  • (160.1190) Materials : Anisotropic optical materials
  • (260.2110) Physical optics : Electromagnetic optics
  • (290.5825) Scattering : Scattering theory

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