42,438 research outputs found
Detection of leaf structures in close-range hyperspectral images using morphological fusion
Close-range hyperspectral images are a promising source of information in plant biology, in particular, for in vivo study of physiological changes. In this study, we investigate how data fusion can improve the detection of leaf elements by combining pixel reflectance and morphological information. The detection of image regions associated to the leaf structures is the first step toward quantitative analysis on the physical effects that genetic manipulation, disease infections, and environmental conditions have in plants. We tested our fusion approach on Musa acuminata (banana) leaf images and compared its discriminant capability to similar techniques used in remote sensing. Experimental results demonstrate the efficiency of our fusion approach, with significant improvements over some conventional methods
Recognition and reconstruction of coherent energy with application to deep seismic reflection data
Reflections in deep seismic reflection data tend to be
visible on only a limited number of traces in a common
midpoint gather. To prevent stack degeneration,
any noncoherent reflection energy has to be removed.
In this paper, a standard classification technique in
remote sensing is presented to enhance data quality. It
consists of a recognition technique to detect and extract
coherent energy in both common shot gathers and fi-
nal stacks. This technique uses the statistics of a picked
seismic phase to obtain the likelihood distribution of its
presence. Multiplication of this likelihood distribution
with the original data results in a “cleaned up” section.
Application of the technique to data from a deep seismic
reflection experiment enhanced the visibility of all
reflectors considerably.
Because the recognition technique cannot produce an
estimate of “missing” data, it is extended with a reconstruction
method. Two methods are proposed: application
of semblance weighted local slant stacks after recognition,
and direct recognition in the linear tau-p domain.
In both cases, the power of the stacking process to increase the signal-to-noise ratio is combined with the direct selection of only specific seismic phases. The joint
application of recognition and reconstruction resulted in
data images which showed reflectors more clearly than
application of a single technique
Processing of multispectral thermal IR data for geologic applications
Multispectral thermal IR data were acquired with a 24-channel scanner flown in an aircraft over the E. Tintic Utah mining district. These digital image data required extensive computer processing in order to put the information into a format useful for a geologic photointerpreter. Simple enhancement procedures were not sufficient to reveal the total information content because the data were highly correlated in all channels. The data were shown to be dominated by temperature variations across the scene, while the much more subtle spectral variations between the different rock types were of interest. The image processing techniques employed to analyze these data are described
Resonant coupling between localized plasmons and anisotropic molecular coatings in ellipsoidal metal nanoparticles
We present an analytic theory for the optical properties of ellipsoidal
plasmonic particles covered by anisotropic molecular layers. The theory is
applied to the case of a prolate spheroid covered by chromophores oriented
parallel and perpendicular to the metal surface. For the case that the
molecular layer resonance frequency is close to being degenerate with one of
the particle plasmon resonances strong hybridization between the two resonances
occur. Approximate analytic expressions for the hybridized resonance
frequencies, their extinction cross section peak heights and widths are
derived. The strength of the molecular - plasmon interaction is found to be
strongly dependent on molecular orientation and suggest that this sensitivity
could be the basis for novel nanoparticle based bio/chemo-sensing applications.Comment: 11 pages, 5 figure
Plasmonics: Localization and guiding of electromagnetic energy in metal/dielectric structures
We review the basic physics of surface-plasmon excitations occurring at metal/dielectric interfaces with special emphasis on the possibility of using such excitations for the localization of electromagnetic energy in one, two, and three dimensions, in a context of applications in sensing and waveguiding for functional photonic devices. Localized plasmon resonances occurring in metallic nanoparticles are discussed both for single particles and particle ensembles, focusing on the generation of confined light fields enabling enhancement of Raman-scattering and nonlinear processes. We then survey the basic properties of interface plasmons propagating along flat boundaries of thin metallic films, with applications for waveguiding along patterned films, stripes, and nanowires. Interactions between plasmonic structures and optically active media are also discussed
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