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1.
Mosaicing is connecting two or more images and making a new wide area image with no visible seam-lines. Several algorithms
have been proposed to construct mosaics from image sequence where the camera motion is more or less complex. Most of these
methods are based either on the interest points matching or on theoretical corner models. This paper describes a fully automated
image-mosaicing method based on the regions and the Harris points primitives. Indeed, in order to limit the search window
of potential homologous points, for each point of interest, regions segmentation and matching steps are being performed. This
enables us to improve the reliability and the robustness of the Harris points matching process by estimating the camera motion.
The main originality of the proposed system resides in the preliminary manipulation of regions matching, thus making it possible
to estimate the rotation, the translation and the scale factor between two successive images of the input sequence. This estimation
allows an initial alignment of the images along with the framing of the interest points search window, and therefore reducing
considerably the complexity of the interest points matching algorithm. Then, the resolution of a minimization problem, altogether
considering the couples of matched-points, permits us to perform the homography. In order to improve the mosaic continuity
around junctions, radiometric corrections are applied. The validity of the herewith described method is illustrated by being
tested on several sequences of complex and challenging images captured from real-world indoor and outdoor scenes. These simulations
proved the validity of the proposed method against camera motions, illumination variations, acquirement conditions, moving
objects and image noise. To determine the importance of the regions matching stage in motion estimation, as well as for the
framing of the search window associated to a point of interest, we compared the matching points results of this described
method with those produced using the zero-mean normalized cross correlation score (without regions matching). We made this
comparison in the case of a simple motion (without the presence of a rotation around optical axis and/or a scale factor),
in the case of a rotation and in the general case of an homothety. For justifying the effectiveness of this method, we proposed
an objective assessment by defining a reconstruction error.
相似文献
Slim AmriEmail: |
2.
Chovin A Garrigue P Pecastaings G Saadaoui H Manek-Hönninger I Sojic N 《Ultramicroscopy》2006,106(2):57-65
We present the fabrication and the characterization of high-density microarrays comprising thousands of near-field optical probes. Two types of microarrays have been prepared by adapting the SNOM methodology: arrays of uncoated fiber nanotips (i.e. apertureless probes) and arrays of apertures with adjustable subwavelength dimensions. Such arrays were fabricated by retaining the coherent structure of monomode optical fiber bundles and therefore keeping their imaging properties. The size of the apertures in a microarray was tuned at the nanometer scale by modifying the fabrication parameters. Far-field characterization of these near-field probe arrays shows completely different behavior depending both on their architecture and on their characteristic size. The angular distribution of the far-field intensity transmitted through the aperture arrays is used to determine the optical size of such diffracting apertures. Aperture radii ranging from 95 to 250 nm were found in good agreement with SEM data. Furthermore, each nanoaperture of the array is optically independent in the far-field regime. Eventually, this study demonstrates potential applications of these imaging arrays as parallel near-field optical probes in both configurations (apertureless and with apertures). 相似文献
3.
Romain Cauchois Mohamed Saadaoui Abdelwahhab Yakoub Karim Inal Beatrice Dubois-Bonvalot Jean-Christophe Fidalgo 《Journal of Materials Science》2012,47(20):7110-7116
The effect of thermal profile on microstructure is studied in the frame of thin films deposited by inkjet-printing technology. The role of sintering temperature and thermal ramp is particularly investigated. Fast heating ramps exhibit coarse grains and pores, especially when a hybrid microwave curing is performed. This enhanced growth is attributed to the quick activation of densifying sintering regimes without undergoing thermal energy loss at low temperature. Microstructural evolution of various sintered inkjet-printed films is correlated with electrical resistivity and with the Young’s modulus determined by nanoindentation. A strong link between those three parameters is highlighted during experiments giving credit to either a surface or a fully volumetric sintering, according to the process. Sintering is then mainly triggered by surface mass transfer or by grain boundary diffusion. Silver thin films with an electrical resistivity 4–5 times higher than the bulk, has been reached in a few minutes with a Young’s modulus of 38?GPa. 相似文献
4.
Effects of Bismuth Doping on the Physical Properties of La0.6−x
Bi
x
Sr0.4CoO3 (0≤x≤0.15) Cobaltites
F. Saadaoui M. Koubaa W. Cheikhrouhou-Koubaa A. Cheikhrouhou 《Journal of Superconductivity and Novel Magnetism》2013,26(10):3043-3047
The structural and magnetic properties of cobaltites with the nominal composition La0.6?x Bi x Sr0.4CoO3 (0≤x≤0.15) have been investigated. X-ray diffraction analysis using Rietveld refinement show that all our samples crystallize in the rhombohedral structure. The zero field cooled (ZFC) and field cooled (FC) magnetization curves at 50 mT exhibits thermomagnetic irreversibility signature of short range ferromagnetic interactions in our samples. The ferromagnetic–paramagnetic transition temperature decreases with increasing Bi amount. In the paramagnetic phase, all our synthesized samples obey to the Curie–Weiss law. The Curie–Weiss analysis suggests that the spin state of Co3+ is IS while Co4+ ions are in IS for x=0 and LS for x≥0.05. The Bi doping also leads to a weakening in the magnetic moment. The magnetic entropy change exhibits a maximum value which decreases from 2.28 J/kg?K for x=0 to 1.24 J/kg?K for x=0.15 upon a magnetic field change of 5 T. 相似文献
5.
A technique developed to self assemble solid colloidal particles under a sinusoidal electric field (AC field) is adapted to soft W/O/W double‐emulsion globules, and is exploited for surface patterning. Double‐emulsions containing cupric ions are prepared, placed between two planar ITO electrodes and submitted to a transversal AC field which induced their ordering into hexagonal 2D‐arrays. The characteristic spacing is monitored by varying the globule volume fraction. Such self‐assembly is used to fabricate copper‐depleted arrays, using globules as both a metal precursor reservoir/provider and as a mask. The ordered globule monolayer is then submitted to a DC field to induce metal precursor leakage and its reduction onto the electrode. The organized, oily and dielectric globules generate arrays of holes (c.a. 7 μm) into a thin copper deposit (thickness of 12 nm). Holes are shown to be formed below the globules, and their separation (from 10 to 30 μm) can be tuned as deduced from direct observations using optical and atomic force microscopy. 相似文献
6.
M. Gassoumi M.M. Ben SalemS. Saadaoui B. GrimbertJ. Fontaine C. gaquiereH. Maaref 《Microelectronic Engineering》2011,88(4):370-372
In AlGaN/GaN heterostructure field-effect transistors, the surface defects and dislocations may serve as trapping centers and affect the device performance via leakage current. In this paper we report results of our investigation of the trapping characteristics of Al0.25Ga0.75N/GaN HEMT using the Conductance Deep Level Transient Spectroscopy (CDLTS). Two deep level electronic defects were observed labeled E1 and HL1, with activation energies Ea1 = 1.36 eV and Ea2 = 0.63 eV. The hole-trap HL1 is characterized for the first time in our studies. We identified the characteristics of the traps at the AlGaN/GaN interface adjoining the channel and the surface along the ungated region between the gate and the drain, as well as the effects of the surface traps. 相似文献
7.
Naceur Etteyeb Leila Dhouibi Mercedes Sanchez Cruz Alonso Carmen Andrade Ezzeddine Triki 《Journal of Materials Science》2007,42(13):4721-4730
The aim of this study is to investigate the viability of use of sodium phosphate (Na3PO4: SP), tetrasodium pyrophosphate (Na4P2O7: TSPP) and hydroxyethylidene-diphosphonic acid (C2H8O7P2: HEDP) as a non-toxic corrosion inhibitors of steel bars in alkaline media which simulate the electrolyte in the concrete
pores. The effectiveness of these phosphate compounds as corrosion inhibitors was investigated by measuring the corrosion
potentials, the polarization curves, the corrosion current densities, and the electrochemical impedance spectroscopy of steel
bars immersed for 30 days in saturated Ca(OH)2 solutions with and without chlorides. At the completion of the tests, the mass losses were determined in order to verify
the reliability of the electrochemical results. The results showed that phosphate compounds form a protective layer on the
steel surface when immersed in alkaline solution without chlorides. In the presence of chloride ions, the SP acts as an anodic
inhibitor and reduces the corrosion activity on steel. The HEDP shows lower efficiency, probably due to the decrease of the
pH and to the high [Cl−]/[inh] ratio used. Results obtained by electrochemical and gravimetric methods are in quite reasonable agreement. 相似文献
8.
This article presents a design methodology for linearizing GaN HEMT amplifiers based on splitting a large FET into multiple parallel FETs with same total gate periphery and by biasing them individually. By varying the biases, the magnitude and the phase of the IMD3 components at the output of FET changes. A detailed simulation methodology using commercial microwave CAD software is presented. Simulation results show that by biasing one device in Class AB and other(s) in deep Class AB mode, IMD3 components of parallel FETs can be made out of phase to each other leading to cancellation and improvement in linearity. Three prototype circuits were simulated using (a) a single 5 mm FET (1 × 5 mm), (b) two parallel 2.5 mm FETs (2 × 2.5 mm), and (c) four parallel 1.25 mm FETs (4 × 1.25 mm), for a total gate periphery of 5 mm, over the frequency range of 0.8 to 1.0 GHz. IMD3 improvement up to 20 dBc was achieved with the 4 × 1.25 mm circuit when the FET biases were optimized. Measurement results show improvement in linearity up to 20 dBc for 4 × 1.25 mm circuit. The proposed method improves linearity without a substantial penalty on the power consumption and is straightforward to implement. 相似文献
9.
10.
Kerbiche Asma Jabra Saoussen Ben Zagrouba Ezzeddine Charvillat Vincent 《Multimedia Tools and Applications》2018,77(20):26769-26791
Multimedia Tools and Applications - Video watermarking technique aims at resolving insecurity problems. Recently, many approaches have been proposed in order to satisfy the new constraints of video... 相似文献