Color transfer method preserving perceived lightness

Color transfer originally proposed by Reinhard et al. is a method to change the color appearance of an input image by using the color information of a reference image. The purpose of this study is to modify color transfer so that it works well even when the scenes of the input and reference images are not similar. Concretely, a color transfer method with lightness correction and color gamut adjustment is proposed. The lightness correction is applied to preserve the perceived lightness which is explained by the Helmholtz–Kohlrausch (H–K) effect. This effect is the phenomenon that vivid colors are perceived as brighter than dull colors with the same lightness. Hence, when the chroma is changed by image processing, the perceived lightness is also changed even if the physical lightness is preserved after the image processing. In the proposed method, by considering the H–K effect, color transfer that preserves the perceived lightness after processing is realized. Furthermore, color gamut adjustment is introduced to address the color gamut problem, which is caused by color space conversion. The effectiveness of the proposed method is verified by performing some experiments.     

Lagrange multiplier and singular limit of double obstacle problems for the Allen–Cahn equation with constraint

We study the properties of the Lagrange multiplier for an Allen–Cahn equation with a double obstacle potential. Here, the dynamic boundary condition, including the Laplace–Beltrami operator on the boundary, is investigated. We then establish the singular limit of our system and clarify the limit of the solution and the Lagrange multiplier of our problem. We present remarks on a trace problem as well as on the Neumann boundary condition. Moreover, we describe a numerical experiment for a problem with Neumann boundary condition using the Lagrange multiplier. Copyright © 2016 John Wiley & Sons, Ltd.     

Mitigation of Diffraction Fringe in Quasi-Far Field Pattern Using an Edge-Shaped Plate

A new concept is developed for improving the laser intensity distribution in quasi-far field using geometrical optics of a continuous phase (so-called edge-shaped plate). The diffraction fringe on a quasi-far field beam pattern of a well collimated He-Ne laser beam 5 cm in diameter is mitigated by the insertion of an edge-shaped plate with a super-Gaussian (n=40) surface profile. A diffraction code using Fresnel-Kirchhoff diffraction integration was developed to calculate diffraction patterns of aspherical optical elements. The measured beam profile is in good agreement with the calculated beam pattern.     

Simultaneous imaging of Mie scattering,PAHs laser induced fluorescence and soot laser induced incandescence to a lab-scale turbulent jet pulverized coal flame

In this study, transient soot formation processes in a small-scale jet burner (CRIEPI burner) were investigated by simultaneous measurements of coal particles, polycyclic aromatic hydrocarbons (PAHs) and soot. Pairs of simultaneous measurements of “Mie scattering measurement for coal particles with laser induced fluorescence (LIF) for PAHs” and “LIF for PAHs with laser induced incandescence (LII) for soot” were performed to understand the transitive formation processes of soot formation in pulverized coal flame, whose signals were successfully separated. Findings in the present study are as follows. Coal particles, PAHs and soot were distributed in this order in radial direction from the central axis. Existing regions of coal particles, PAHs and soot were overlapped from the time averaged viewpoint while there were few overlapping areas of coal particles, PAHs and soot from the instantaneous viewpoint. This result indicates that a long time is required for the formation of soot from 2 to 3 rings PAHs through larger PAHs.     

Periodic Solutions of Elliptic-Parabolic Variational Inequalities with Time-Dependent Constraints

We study periodic solutions of quasilinear elliptic-parabolic variational inequalities with time-dependent constraints. Assuming that the constraint changes periodically in time, we prove existence of periodic solutions. Moreover, applications of the general results are given.     

Effect of charge ordering and disordering on terahertz radiation characteristics of magnetoresistive Pr0.7Ca0.3MnO3 thin films

Terahertz (THz) radiation from voltage-biased photoswitching devices made on magnetoresistive manganite Pr0.7Ca0.3MnO3 have been investigated for thin films grown under different conditions. We find that the temperature dependence of THz radiation near the charge-ordering temperature strongly depends on the growth condition of Pr0.7Ca0.3MnO3, whereas THz radiation shows no such temperature dependence near the spin-ordering temperature.     

Blind deconvolution under band limitation

A blind deconvolution problem is newly stated with the following conditions: the point-spread function is band limited, both the object and the point-spread function are nonnegative, and the solution is to be a diffraction-limited object. A blind deconvolution method was developed that can easily be applied to problems in optics because of the conditions used. The performance of the method is investigated with computer simulations.     

The structure of tetronolide,the aglycone of antitumor antibiotic tetrocarcin

X-ray analysis has determined the structure of tetronolide, which has a unique spiro γ-lactone group.     

Population inversion by near-resonant sequential optical pulses

Population inversion by near-resonant sequential optical pulses is proposed. A complete understanding of the population inversion by the near-resonant optical pulses is provided by the vector model.