Sky Based Light Metering for High Dynamic Range Images

Image calibration requires both linearization of pixel values and scaling so that values in the image correspond to real‐world luminances. In this paper we focus on the latter and rather than rely on camera characterization, we calibrate images by analysing their content and metadata, obviating the need for expensive measuring devices or modeling of lens and camera combinations. Our analysis correlates sky pixel values to luminances that would be expected based on geographical metadata. Combined with high dynamic range (HDR) imaging, which gives us linear pixel data, our algorithm allows us to find absolute luminance values for each pixel—effectively turning digital cameras into absolute light meters. To validate our algorithm we have collected and annotated a calibrated set of HDR images and compared our estimation with several other approaches, showing that our approach is able to more accurately recover absolute luminance. We discuss various applications and demonstrate the utility of our method in the context of calibrated color appearance reproduction and lighting design.     

Evaluating the Impact of User Characteristics and Different Layouts on an Interactive Visualization for Decision Making

There is increasing evidence that user characteristics can have a significant impact on visualization effectiveness, suggesting that visualizations could be designed to better fit each user's specific needs. Most studies to date, however, have looked at static visualizations. Studies considering interactive visualizations have only looked at a limited number of user characteristics, and consider either low‐level tasks (e.g., value retrieval), or high‐level tasks (in particular: discovery), but not both. This paper contributes to this line of work by looking at the impact of a large set of user characteristics on user performance with interactive visualizations, for both low and high‐level tasks. We focus on interactive visualizations that support decision making, exemplified by a visualization known as Value Charts. We include in the study two versions of ValueCharts that differ in terms of layout, to ascertain whether layout mediates the impact of individual differences and could be considered as a form of personalization. Our key findings are that (i) performance with low and high‐level tasks is affected by different user characteristics, and (ii) users with low visual working memory perform better with a horizontal layout. We discuss how these findings can inform the provision of personalized support to visualization processing.     

Learning Natural Colors for Image Recoloring

We present a data‐driven method for automatically recoloring a photo to enhance its appearance or change a viewer's emotional response to it. A compact representation called a RegionNet summarizes color and geometric features of image regions, and geometric relationships between them. Correlations between color property distributions and geometric features of regions are learned from a database of well‐colored photos. A probabilistic factor graph model is used to summarize distributions of color properties and generate an overall probability distribution for color suggestions. Given a new input image, we can generate multiple recolored results which unlike previous automatic results, are both natural and artistic, and compatible with their spatial arrangements.     

Illuminant Aware Gamut‐Based Color Transfer

This paper proposes a new approach for color transfer between two images. Our method is unique in its consideration of the scene illumination and the constraint that the mapped image must be within the color gamut of the target image. Specifically, our approach first performs a white‐balance step on both images to remove color casts caused by different illuminations in the source and target image. We then align each image to share the same ‘white axis’ and perform a gradient preserving histogram matching technique along this axis to match the tone distribution between the two images. We show that this illuminant‐aware strategy gives a better result than directly working with the original source and target image's luminance channel as done by many previous methods. Afterwards, our method performs a full gamut‐based mapping technique rather than processing each channel separately. This guarantees that the colors of our transferred image lie within the target gamut. Our experimental results show that this combined illuminant‐aware and gamut‐based strategy produces more compelling results than previous methods. We detail our approach and demonstrate its effectiveness on a number of examples.     

Heterogeneous asymmetric reactions. 23. Enantioselective hydrogenation of ethyl pyruvate over cinchonine- and α-isocinchonine-modified platinum catalysts

The enantioselective hydrogenation of ethyl pyruvate to (S)-ethyl lactate over cinchonine- and mg src="/content/m12vn2x82w47805w/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-isocinchonine-modified Pt/Al₂O₃ catalysts was studied as a function of modifier concentration and reaction temperature. The maximum enantioselectivities obtained under the applied mild conditions were 89% ee using cinchonine (0.014 mmolmg src="/content/m12vn2x82w47805w/xxlarge8201.gif" alt="thinsp" align="MIDDLE" BORDER="0">dm^{–3}, 1 bar H₂, 23mg src="/content/m12vn2x82w47805w/xxlarge8201.gif" alt="thinsp" align="MIDDLE" BORDER="0">°C, 6% AcOH in toluene), and 76% ee in the case of mg src="/content/m12vn2x82w47805w/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-isocinchonine (0.14 mmolmg src="/content/m12vn2x82w47805w/xxlarge8201.gif" alt="thinsp" align="MIDDLE" BORDER="0">dm^{–3}, 1 bar H₂, –10mg src="/content/m12vn2x82w47805w/xxlarge8201.gif" alt="thinsp" align="MIDDLE" BORDER="0">°C, 6% AcOH in toluene). Since mg src="/content/m12vn2x82w47805w/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-isocinchonine of rigid structure exists only in mg src="/content/m12vn2x82w47805w/xxlarge8220.gif" alt="ldquo" align="MIDDLE" BORDER="0">anti-openmg src="/content/m12vn2x82w47805w/xxlarge8221.gif" alt="rdquo" align="MIDDLE" BORDER="0"> conformation these data provide additional experimental evidence to support the former suggestion concerning the dominating role of mg src="/content/m12vn2x82w47805w/xxlarge8220.gif" alt="ldquo" align="MIDDLE" BORDER="0">anti-openmg src="/content/m12vn2x82w47805w/xxlarge8221.gif" alt="rdquo" align="MIDDLE" BORDER="0"> conformation in these cinchona-modified enantioselective hydrogenations.     

Fluorinated γ-alumina aerogels and xerogels: characterisation and catalytic behaviour

The porosity of mg src="/content/m5086085257117m2/xxlarge947.gif" alt="gamma" align="MIDDLE" BORDER="0">-alumina-based materials is an important parameter affecting the extent of fluorination (aerogels > commercial mg src="/content/m5086085257117m2/xxlarge947.gif" alt="gamma" align="MIDDLE" BORDER="0">-Al₂O₃ > xerogels) and, consequently, also the textural, acidic and catalytic properties of the final fluorinated materials. Only the highly fiuorinated aluminas having strong Lewis acidic sites catalyse the isomerisation of CHF₂CHF₂ to CF₃CH₂F.     

Oligomer-Rich Fraction from Polydisperse Sample of Poly(bis(β-phenoxyethoxy)phosphazene)

Poly[bis(mg src="/content/m3872066213858xq/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-phenoxyethoxy)phosphazene] [PBPEP] had been shown in our previous paper to be a very useful polymer for investigating the crystallization mechanism of polymers, as the crystallization rate of PBPEP is extraordinarily small when isothermally crystallized from the melt. The crystallization of the low molecular weight oligomers of PBPEP was first studied in comparison to the high molecular weight polymers. The oligomer-rich fraction was obtained by fractionation of the as-polymerized sample, which had a broad molecular weight distribution. The fractions thus obtained were characterized by solution viscometry and size exclusion chromatography. The melting temperature and the growth rate of the spherulite from the melt were investigated by differential scanning calorimetry and optical microscopy. The growth rate was one or two orders of magnitude smaller in the oligomer-rich fraction than in the other high molecular weight fractions. A collapsed spherulite appeared in the oligomer-rich fraction at high crystallization temperatures. It is speculated that in the oligomer-rich fraction there is an excess free energy due to defects in the crystal phase. This defect is considerably larger in the oligomer-rich fraction than in the other fractions because a large quantity of short length chains is present.     

13C n.m.r. study of raw materials for carbon black

¹³C n.m.r. spectroscopy has been applied to investigate a number of coal tar and petroleum-derived carbon black feedstocks. Application of the m>Jm>-modulated spin echo technique is especially rewarding, as this method renders the quaternary carbons directly detectable. Thus the quality of carbon black feedstocks can additionally be gauged on the basis of the contents of quaternary carbons, which is a direct indication of the carbon yield in the carbon black production process.     

Analysis of epoxidized natural rubber. A comparative study of d.s.c., n.m.r., elemental analysis and direct titration methods

A comparative analysis of epoxidized natural rubber samples by ¹H and ¹³C n.m.r., titrimetric, elemental and d.s.c. techniques has been made. Whereas the titrimetric method is only applicable at low epoxy contents (< 15 mol%) both n.m.r. methods give reasonable precision over the compositional range of 20–75 mol%. Elemental analysis appears less reliable. D.s.c. analysis through measurement of m>Tm>_g provides the highest precision of measurement but requires independent calibration by one or more of the primary methods. The epoxy content may also be related to the polymer density.     

The influence of an intermediate MoO3 layer on the solid state reaction of cobalt oxide withγ-Al2O3

In view of the importance for Co_xO_y,-MoO₃/mg src="/content/m608451j26813318/xxlarge947.gif" alt="gamma" align="MIDDLE" BORDER="0">-Al₂O₃ hydrodesulphurization (HDS) catalysts, the reactivity of cobalt oxide layers towards cobalt aluminate formation was investigated on both MoO₃-covered and bare mg src="/content/m608451j26813318/xxlarge947.gif" alt="gamma" align="MIDDLE" BORDER="0">-Al₂O₃ substrates. Co₃O₄/MoO₃/mg src="/content/m608451j26813318/xxlarge947.gif" alt="gamma" align="MIDDLE" BORDER="0">-Al₂O₃ and Co₃O₄/mg src="/content/m608451j26813318/xxlarge947.gif" alt="gamma" align="MIDDLE" BORDER="0">-Al₂O₃ systems were prepared by vapour-deposition of MoO₃ (12 × 10¹⁵ Mo atoms/cm²) and Co (400 × 10¹⁵ Co atoms/cm²) layers onto a mg src="/content/m608451j26813318/xxlarge947.gif" alt="gamma" align="MIDDLE" BORDER="0">-Al₂O₃ substrate, followed by oxidation of the Co layer to Co₃O₄. After annealing at 800°C for 40 h, the interfacial reaction to cobalt aluminate was assessed using Rutherford backscattering spectrometry. The presence of molybdenum oxide appeared to enhance cobalt aluminate formation. The Mo atoms, which spread out over the entire cobalt-containing layer, presumably caused a high defect density, which explains the observed higher reaction rate. The amount of MoO₃ was much too low to stabilize all cobalt atoms by cobalt molybdate formation.