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Local Color Mapping Combined with Color Transfer for Underwater Image Enhancement(2019 IEEE Winter Conference on Applications of Computer Vision (WACV), Institute of Electrical and Electronics Engineers (IEEE), 2019-03-08) [Conference Paper]Color correction and color transfer methods have gained a lot of attention in the past few years to circumvent color degradation that may occur due to various sources. In this paper, we propose a novel simple yet powerful strategy to profoundly enhance color distorted underwater images. The proposed approach combines both local and global information through a simple yet powerful affine transform model. Local and global information are carried through local color mapping and color covariance mapping between an input and some reference source, respectively. Several experiments on degraded underwater images demonstrate that the proposed method performs favourably to all other methods including ones that are tailored to correcting underwater images by explicit noise modelling.
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Colorful seashells: Identification of haem pathway genes associated with the synthesis of porphyrin shell color in marine snails(Ecology and Evolution, Wiley, 2017-10-30) [Article]Very little is known about the evolution of molluskan shell pigments, although Mollusca is a highly diverse, species rich, and ecologically important group of animals comprised of many brightly colored taxa. The marine snail genus Clanculus was chosen as an exceptional model for studying the evolution of shell color, first, because in Clanculus margaritarius and Clanculus pharaonius both shell and foot share similar colors and patterns; and second, because recent studies have identified the pigments, trochopuniceus (pink-red), and trochoxouthos (yellow-brown), both comprised of uroporphyrin I and uroporphyrin III, in both shell and colored foot tissue of these species. These unusual characteristics provide a rare opportunity to identify the genes involved in color production because, as the same pigments occur in the shell and colored foot tissue, the same color-related genes may be simultaneously expressed in both mantle (which produces the shell) and foot tissue. In this study, the transcriptomes of these two Clanculus species along with a third species, Calliostoma zizyphinum, were sequenced to identify genes associated with the synthesis of porphyrins. Calliostoma zizyphinum was selected as a negative control as trochopuniceus and trochoxouthos were not found to occur in this species. As expected, genes necessary for the production of uroporphyrin I and III were found in all three species, but gene expression levels were consistent with synthesis of uroporphyrins in mantle and colored foot tissue only in Clanculus. These results are relevant not only to understanding the evolution of shell pigmentation in Clanculus but also to understanding the evolution of color in other species with uroporphyrin pigmentation, including (mainly marine) mollusks soft tissues and shells, annelid and platyhelminth worms, and some bird feathers.
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Plasmonic color-graded nanosystems with achromatic sub-wavelength architectures for light filtering and advanced SERS detection(ACS Applied Materials & Interfaces, American Chemical Society (ACS), 2016-03-09) [Article]Plasmonic colour-graded systems are devices featuring a spatially variable plasmonic response over their surface. They are widely used as nanoscale colour filters; their typical size is small enough to allow integration with miniaturized electronic circuits paving the way to realize novel nanophotonic devices. Currently, most plasmonic colour-graded systems are intrinsically discrete, as their chromatic response exploits the tailored plasmon resonance of micro-architectures characterized by different size and/or geometry for each target colour. Here we report the realization of multifunctional plasmon-graded devices where continuously-graded chromatic response is achieved by smoothly tuning the composition of the resonator material while simultaneously maintaining an achromatic nanoscale geometry. The result is a new class of versatile materials: we show their application as plasmonic filters with a potential pixel size smaller than half of the exciting wavelength, but also as multiplexed surface-enhanced Raman spectroscopy (SERS) substrates. Many more implementations, like photovoltaic efficiency boosters or colour routers await, and will benefit from the low fabrication cost and intrinsic plasmonic flexibility of the presented systems.
