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21.
Multispectral Image Compression for Improvement of Colorimetric and Spectral Reproducibility by Nonlinear Spectral Transform 总被引:1,自引:0,他引:1
Shanshan Yu Yuri Murakami Takashi Obi Masahiro Yamaguchi Nagaaki Ohyama 《Optical Review》2006,13(5):346-356
The article proposes a multispectral image compression scheme using nonlinear spectral transform for better colorimetric and
spectral reproducibility. In the method, we show the reduction of colorimetric error under a defined viewing illuminant and
also that spectral accuracy can be improved simultaneously using a nonlinear spectral transform called Labplus, which takes
into account the nonlinearity of human color vision. Moreover, we show that the addition of diagonal matrices to Labplus can
further preserve the spectral accuracy and has a generalized effect of improving the colorimetric accuracy under other viewing
illuminants than the defined one. Finally, we discuss the usage of the first-order Markov model to form the analysis vectors
for the higher order channels in Labplus to reduce the computational complexity. We implement a multispectral image compression
system that integrates Labplus with JPEG2000 for high colorimetric and spectral reproducibility. Experimental results for
a 16-band multispectral image show the effectiveness of the proposed scheme. 相似文献
22.
Using scattered radiation as useful information to improve radioisotope image quality is a topic attracting many researchers. Some reports showed that incorporating scattered components offers a possibility to improve image quality. The general method is modeling scatter in multiple energy windows and incorporating that information into the reconstruction process. However, what the performance will be and how noise will behave when using scattered radiation in reconstruction are not yet well answered. In this paper, we investigate a method of modeling scatter in multiple energy windows in cases of a few projection views. The system performance is analyzed using singular value decomposition and resolution kernels. For noise behavior investigation, reconstructions are accomplished by estimating the variance of reconstructed voxel values and the effectiveness of using scatter is evaluated by resolution kernel analysis. The results show there are improvements in normalized mean-square error of the images and the resolution kernels. When photon counts fall below about one million, it is still effective to use scatter for some cases of a few projections 相似文献
23.
We have generated thep-cyanobenzyl radical in supersonic free expansion, and measured the vibrationally and rotationally resolved laser induced fluorescence (LIF) excitation spectra and the LIF dispersed spectra from the single vibronic levels (SVL) in the green-blue region. The lowest energy band at 20 738 cm−1with the strongest intensity in the excitation spectrum has been assigned to the 000band of the visible spectrum, on the basis of the vibronic structures in the SVL dispersed spectra. Based on the band type of the 000band,a-type, determined from the rotationally resolved LIF excitation spectrum, we have definitely assigned the visible band to theD122B1–D012B1electronic transition. We have found, on the grounds of the vibrational analysis of the dispersed spectra, that the vibronic structure of the 22B1–12B1electronic transition of the benzyl type is characterized by totally symmetric fundamental modes, 1, 8a, and 9a. 相似文献
24.
C. Uma Maheswari K. Obi Reddy E. Muzenda M. Shukla A. Varada Rajulu 《International Journal of Polymer Analysis and Characterization》2013,18(6):439-450
In this work, composite samples were prepared using Borassus fibers and a high-density polyethylene matrix. Alternatively, a chemically modified matrix (maleic anhydride grafted HDPE) was also used to improve fiber-matrix compatibility. The effect of fiber loading on the mechanical properties was investigated. Borassus fiber/modified HDPE composites exhibited improved mechanical performance as compared to pure HDPE composites. SEM studies on the fractured specimens of unmodified HDPE fiber composites reveal the poor fiber-matrix interaction, whereas the interaction is strong with enhanced mechanical properties for modified HDPE fiber composites. This is due to an improvement of the chemical bonding between the modified HDPE matrix and the Borassus fiber as also supported by Fourier transform infrared spectroscopy results. Thermal stability was also found to be enhanced slightly for modified HDPE composites. 相似文献
25.
The SRVL fluorescenee lifetimes and fluorescence excitation spectra of the HNO ã1A″ -X1AA′ transition were measured in a supersonic free jet. The cooling of a rotational temperature in the jet made it possible to clear up the parity-selected perturbations in the asymmetric rotor under higher resolution condition. The fluorescence lifetimes of strongly perturbed levels, i.e. HNO ã1A″ 011 rovibronic levels were observed with dual exponential decay profiles, while non-perturbed levels exhibited single ones. The SRVL fluorescence lifetimes and fluorescence excitation spectra of DNO ã1″ -X1A′ were measured under the same condition as HNO. The rotationll analysis of the DNO ã1A″ 011 rovibronic levels was first carried out in the jet. 相似文献
26.
An organocatalyst-mediated, asymmetric Mannich reaction in the presence of water without using organic solvents has been developed. A highly reactive siloxytetrazole hybrid catalyst has been developed for the reaction of dimethoxyacetaldehyde, while the sodium salt of siloxyproline is an effective catalyst of alpha-imino glyoxylate. Excellent enantioselectivity can be realized, and the usage of organic solvents can be reduced compared to the conventional reactions in organic solvents. 相似文献
27.
Takuya Kawata Yoshitsugu Naka Koji Fukagata Shinnosuke Obi 《Flow, Turbulence and Combustion》2011,86(3-4):419-437
We have developed a probe-system for simultaneous measurement of three velocity components and pressure in turbulent flows. A miniature total pressure probe is placed adjacent to the sensors of a triple hot-film probe in order to achieve the spatial resolution which is equivalent to that of the triple hot-film probe itself. The instantaneous static pressure is calculated from measured velocity and total pressure by means of a newly developed processing method based on the Bernoulli equation for unsteady flows. The measurements were undertaken in a turbulent wing-tip vortex flow. The look-up table method is employed for the calibration of the hot-film probe so accurate velocity data could be obtained over a wide range of the flow-attack angles. It is also demonstrated that the present probe-system is capable of measuring fluctuations in both velocity and pressure in the 20?C650 Hz frequency range. The distribution of the fluctuating pressure obtained by this indirect method is in good agreement with the results from direct measurements of static pressure, demonstrating the promising performance of the present method. Furthermore, an improvement in the ability to make measurements of the velocity?Cpressure correlation across the wing-tip vortex is achieved. This improvement is possible because the effects of lateral velocity components are properly taken into account in the present formulation. The investigation regarding the transport equation budget for turbulent kinetic energy shows an anomalous structure of turbulence in this flow, mainly due to the meandering of the vortex, and the measurement of pressure diffusion is found to play an important role in the characterization of this kind of flow. 相似文献
28.
Taniguchi T Obi S Kamata Y Kashiwakura T Kasuya M Ogawa T Kohri M Nakahira T 《Journal of colloid and interface science》2012,368(1):107-114
The organic/inorganic hybrid particles PSt/P(St-CPEM)(θ)-g-PDMAEMA/SiO(2) were prepared by catalytic hydrolysis and subsequent polycondensation of tetraethoxysilane in the poly[2-(N,N-dimethylamino)ethyl methacrylate] (PDMAEMA) layers grafted on the PSt/P(St-CPEM)(θ) core/shell heterocoagulates. The micron-sized PSt core and the submicron-sized P(St-CPEM) shell particles bearing ATRP initiating groups were synthesized by dispersion polymerization of styrene (St) and emulsifier-free emulsion polymerization of St with 2-chloropropionyloxyethyl methacrylate (CPEM), respectively. The raspberry-shaped PSt/P(St-CPEM)(θ) heterocoagulates with a controlled surface coverage (θ=0.51, 0.81) were prepared by hydrophobic coagulation between the core and the shell particles in an aqueous NaCl solution near the T(g) of P(St-CPEM). Surface modification of heterocoagulates was carried out by ATRP of DMAEMA from the shell particles adsorbed on the core particles. Silica deposition was performed by simply adding tetraethoxysilane to a water/methanol dispersion of PSt/P(St-CPEM)(θ)-g-PDMAEMA. The SEM and TGA revealed that the resulting PSt/P(St-CPEM)(θ)-g-PDMAEMA/SiO(2) composites maintain a raspberry-like morphology after deposition of silica onto the PDMAEMA layer grafted on heterocoagulates. The micron-sized, raspberry-shaped or the submicron-sized, hole-structured silica hollow particles were obtained selectively by thermal decomposition of the PSt/P(St-CPEM)(θ)-g-PDMAEMA/SiO(2). The oriented particle array was fabricated by dropping anisotropically perforated silica particles onto a glass substrate settled at the bottom of a bottle filled with chloroform. 相似文献
29.
Large eddy simulations of turbulent flow between shrouded co-rotating disks, representing a simplified model of a hard disk drive, are performed. The computation domain surrounds a complete disk and is bounded at top and bottom by half a disk. Therefore, it is possible to compute the fluctuating pressure field surrounding the middle disk. Also, the influence of the shroud geometry is taken into account by comparing a flat shroud wall and a wall with rib chambers. In the flat shroud case, the fluctuating pressure on the upper- and lower-surface of a disk indicates a strong correlation with fluid motion travelling across the disk-tip clearance region. However, in the ribbed shroud case the organized flow structure that is observed in the flat shroud case disappears and the fluctuating pressure acting on the surface of the disk is remarkably diminished. 相似文献
30.
Qualitative and quantitative flow visualizations were performed on a flapping rigid plate to establish a quantitative method
for flow observation and evaluation of the force in the near field of a flapping wing. Flow visualization was performed qualitatively
with dye visualization and quantitatively with velocity measurements using stereo particle image velocimetry (PIV) on three
planes near the tip of the plate along its chord and oriented normally. By ensemble averaging the velocity fields of the same
phase angles, they represent a portion of the volume near the tip. Measurements were conducted with two flapping frequencies
to compare the flow structure. The second invariant of the deformation tensor visualized the leading edge and mid-chord vortices
around the plate appearing due to flow separation behind the plate while other vortical structures were visualized by streamlines.
These structures appear to be related to the dynamics of the leading edge vortex. Force analysis by integrating the phase-averaged
velocity field within a chosen control volume showed increases in the maxima of the magnitudes of the non-dimensional unsteady
force terms on the edge of the plate at the angles after the end of each stroke. The non-dimensional phase-averaged momentum
flux was similar for both flapping frequencies. 相似文献