The Geometry of Colors in Van Gogh’s Sunflowers

“Paintings fade like flowers”: van Gogh’s prediction on the impact of age on paintings came true for most of his paintings. We have studied the consequences of this aging on the Sunflowers in a vase with a yellow background series, namely its original, F454, and two replicates, F457 and F458, at the van Gogh’s museum in Amsterdam, which van Gogh painted using the original as a model. The background and flower renditions in those paintings have faded and turned brown, making them less vibrant that van Gogh had most likely intended. We have attempted to restore van Gogh’s intent using a computational approach based on data science. After identifications of regions of interest (ROI) within the three paintings F454, F457, and F458 that capture the flowers, stems of the flowers, and background, respectively, we studied the geometry of the color space (in RGB representation) occupied by those ROIs. By comparing those color spaces with those occupied by similar ROIs in photographs of real sunflowers, we identified shifts in all three color coordinates, R, G, and B, with the positive shift in the blue coordinate being the more salient. We have proposed two algorithms, PCR-1 and PCR-2, for correcting that shift in blue and generate representations of the paintings that aim to restore their original conditions. The reduction of the blue component in the yellow hues has lead to more vibrant and less brownish digital rendition of the three Sunflowers in a vase with a yellow background.

Technique for Removing Unnecessary Superimposed Patterns from Image using Generative Network

A technique for removing unnecessary patterns from captured images by using a generative network is studied. The patterns, composed of lines and spaces, are superimposed onto a blue component image of RGB color image when the image is captured for the purpose of acquiring a depth map. The superimposed patterns become unnecessary after the depth map is acquired. We tried to remove these unnecessary patterns by using a generative adversarial network (GAN) and an auto encoder (AE). The experimental results show that the patterns can be removed by using a GAN and AE to the point of being invisible. They also show that the performance of GAN is much higher than that of AE and that its PSNR and SSIM were over 45 and about 0.99, respectively. From the results, we demonstrate the effectiveness of the technique with a GAN.

Visible Photoluminescence of Variable-Length Zinc Oxide Nanorods Embedded in Porous Anodic Alumina Template for Biosensor Applications

Zinc oxide (ZnO) and porous anodic aluminum oxide (PAAO) are technologically important materials, rich with features that are of interest in optical applications, for example, in light-emitting and sensing devices. Here, we present synthesis method of aligned ZnO nanorods (NR) with 40 nm diameter and variable length in 150 to 500 nm range obtained by atomic layer deposition (ALD) of ZnO in pores of continuously variable thickness PAAO. The relative intensity of yellow (1.99 eV), green (2.35 eV), and blue (2.82 eV) photoluminescence (PL) components originating from the different types of defects, varied with non-monotonic dependency on the composite film thickness with a Fabry–Pérot like modulation. The intensity variation of any individual PL component correlated well with anti-reflective properties of ZnO NR–PAAO composite film at the peak wavelength of the particular PL component. This provides a route for selective enhancement or suppression of color components of hybrid fluorescent emitters by tuning only geometric parameters, with potential use in imaging and other optical devices. As an application example we tested the composite film for sensing of vascular endothelial growth factor (VEGF) using a widely accessible fluorescence microscopy setup. The intensity of the yellow and green PL components reduced in response to increased VEGF concentrations, whereas blue component remained invariant.

Double-peaked Lyman α emission at z = 6.803: a reionization-era galaxy self-ionizing its local H ii bubble

ABSTRACT We report the discovery of a double-peaked Lyman α profile in a galaxy at z = 6.803, A370p_z1, in the parallel Frontier Field of Abell 370. The velocity separation between the blue and red peaks of the Lyman α profile ($\Delta v=101_{-19}^{+38} (\pm 48)\, \rm km\, \rm s^{-1}$) suggests an extremely high escape fraction of ionizing photons $\gt 59(51){{\ \rm per\ cent}} (2\sigma)$. The spectral energy distribution indicates a young (50 Myr), star-forming ($12\pm 6 \, \rm {M}_\odot \rm {yr}^{-1}$) galaxy with an IRAC excess implying strong [O iii] + H β emission. On the basis of the high escape fraction measured, we demonstrate that A370p_z1 was solely capable of creating an ionized bubble sufficiently large to account for the blue component of its Lyman α profile. We discuss whether A370p_z1 may be representative of a larger population of luminous z ≃ 7 double-peaked Lyman α emitting sources with high escape fractions that self-ionized their surroundings without contributions from associated ultraviolet-fainter sources.

The impact of isomers on a kilonova associated with neutron star mergers

ABSTRACT We investigate the significance of isomers on a kilonova associated with neutron star mergers (NSMs) for the first time. We calculate the evolution of abundances and energy generation rates ($\dot{\epsilon }_{\rm nuc}$) of ejecta from NSMs, taking into account β− decay through isomers. We find that for ejecta with electron fraction (Ye) of 0.2–0.3, $\dot{\epsilon }_{\rm nuc}$ is appreciably changed from those without isomers, due to the large change in timing of β− decay through the isomeric states (ISs) of ${}^{123,125,127} \rm Sn$ and ${}^{128} \rm Sb$. In particular, the effects of the isomers on $\dot{\epsilon }_{\rm nuc}$ are prominent for ejecta of Ye ∼ 0.25, which could emit a fraction of an early, blue component of a kilonova observed in GW170817. When the excitation from a ground state to its IS is important, the isomers of ${}^{129} \rm Sb$ and ${}^{129, 131} \rm Te$ also cause additional and appreciable change in $\dot{\epsilon }_{\rm nuc}$. Furthermore, we demonstrate that larger amounts of lanthanide-free ejecta result in a better fit of an observed light curve of the kilonova in GW170817 if the isomers are taken into account.

Hiding Data in the Blue Channel

To enable the track and trace of pages from a color printer, data must be embedded and recoverable across the entire page regardless of the content on that page. This paper describes a solution that allows low visibility and high detectability of databearing “dot signatures”. An analysis of optimum dot-color to background-color combinations uncovers the serendipitous method of “Blue Clipping,” operating only on the blue component, exploiting low visual sensitivity to the blue channel. Blue Clipping is compared to the method of yellow dots, and the problem of dot gain for shadow dots is addressed. While initially designed for enterprise printers, this new technology is also adding functionality to 3D objects. It enables visually pleasing yet robustly recoverable data markings from a small region anywhere on a printed surface, without the need for costly special inks.

Comparative Linguacultural Study of Phraseological Units With the ‘Color blue’ Component in English, Russian and Uzbek Languages as a Reflection of National Specificity

This article is concerned with the problem of national and cultural specifics of Phraseological Units, with the component of color. An object of a research is Phraseological Units with a component of color blue / синий / кўк in the English, Russian and Uzbek languages. A subject of research — national and cultural features of phraseological units with the component of color in English, Russian and Uzbek languages.

Rapid, Wide-Range, and Low-Cost Determination of Formaldehyde Based on Porous Silica Gel Plate by Digital Image Colorimetry

A porous silica gel plate impregnated with a colorimetric reagent, 4-amino-3-penten-2-one (Fluoral-P) has been fabricated for the first time to determinate formaldehyde. The reaction of formaldehyde and Fluoral-P produced a yellow product 3,5-diacetyl-1,4-dihydrolutidine (DDL), which was further photographed by a smartphone. A good linear relationship has been found between the intensity of blue component from the digital image and formaldehyde concentration in the range of 0–50 mg L−1 with low detection limit of 2.2 ± 0.1 mg L−1. A good precision in the range of 0.59–7.75%RSD and an accuracy with the relative error of +3.7% from control samples are also obtained. These results demonstrate that our developed low-cost sensor, together with digital image colorimetry, has potential for sensitively and quickly measuring formaldehyde.