Color removal method considering perceived lightness

Optical Review - A novel color removal method for digital color images is proposed. In this method, differences of colors in an input color image are reflected effectively, and the perceived...     

Color transfer in associated heavy-quarkonium production

We study the production of heavy quarkonium in association with an additional heavy pair. We argue that important contributions may come from phase space regions where three heavy fermions are separated by relative velocities much lower than the speed of light, and to which standard effective field theories do not apply. In this region, infrared sensitive color exchange is specific to the presence of the unpaired (anti)quark. This effect vanishes as the motion of the additional particle becomes relativistic with respect to the pair, and is completely absent for massless quarks and gluons in the final state.     

Pions: unbaring their lightness of being

This lecture describes our understanding of why pions are light and how this is related to the structure of the QCD vacuum. The other lectures, on (i) the hadron world, (ii) dynamical mass generation and (iii) the Schwinger-Dyson approach to strong physics, make up the course Building hadrons with quarks, string and glue.     

渐近保持PIC算法在等离子体粒子模拟中的应用

针对准中性Vlasov-Poisson系统中多尺度物理参数共存的问题开展研究,采用渐近保持格式推导出与Vlasov方程相耦合的Poisson方程。数值模拟了一维等离子体在真空中的膨胀,比较了渐近保持PIC算法与传统PIC算法模拟结果的异同。结果表明：两种算法在满足多尺度中小尺度量限制的前提下,其结果保持高度一致;且在克服小尺度量束缚时,渐近保持PIC算法依然可以正确地模拟等离子体的物理行为,大大节省了计算时间。     

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针对准中性Vlasov-Poisson系统中多尺度物理参数共存的问题开展研究,采用渐近保持格式推导出与Vlasov方程相耦合的Poisson方程。数值模拟了一维等离子体在真空中的膨胀,比较了渐近保持PIC算法与传统PIC算法模拟结果的异同。结果表明：两种算法在满足多尺度中小尺度量限制的前提下,其结果保持高度一致;且在克服小尺度量束缚时,渐近保持PIC算法依然可以正确地模拟等离子体的物理行为,大大节省了计算时间。     

Multi-scale retinex-based contrast enhancement method for preserving the naturalness of color image

Optical Review - For images with insufficient visibility, image processing is required. Retinex theory is often implemented for image contrast enhancement for images with this characteristic. This...     

干涉仪仪器传递函数的检测方法

为了得到干涉仪的空间频率响应特性,开展了针对干涉仪的仪器传递函数的测评方法研究。建立了干涉仪成像系统的仪器传递函数的理论计算模型,利用光学设计软件仿真了菲索型干涉仪检测光路,计算并分析了该干涉系统的仪器传递函数的理论值。对基于特定频率点下的正弦位相板的方法测评干涉仪的仪器传递函数进行仿真分析,并与干涉仪的仪器传递函数的理论值进行了比对,其最大误差不超过0.6%,验证了该方法的正确性。     

Integral transform method in radiative transfer

A method based on integral Fourier transform technique is proposed for obtaining the radiation intensity in a nonconservative, isotropically scattering, finite slab with a general internal isotropic source and with general transparent boundary conditions. The theory of the method is first presented and it is shown to provide an exact analytical solution for the problem. Numerical results for various physical situations are then reported and compared with previous other results wherever possible. The case of the universal functions Θ(τ) and Θ_g(τ) is also considered.     

Color removal method of considering distance in color space

In a color-to-gray conversion, which only considers lightness components, difference of colors are not appropriately reflected in monochrome images. Gooch et al. have proposed a color removal method that considers the differences of colors. Although the method can obtain good results in many cases, there is room for improvement. In this paper, a new color removal method that introduces a weight to Gooch’s algorithm is proposed. In the proposed method, for combinations of colors of each pixel in an input image, weights are determined by distance in color space. In the proposed method, unimportant color combinations are not considered by weight and color information in an input image is appropriately reflected in a monochrome image. The validity of the proposed method is shown by experiments using some images.     

Color representation method using RGB color binary-weighted computer-generated holograms

We propose a method for color electroholography using a simple red–green–blue(RGB) gradation representation method without controlling the respective brightness of the reference RGB-colored lights. The proposed method uses RGB multiple bit planes comprising RGB binary-weighted computer-generated holograms with various light transmittances. The object points of a given three-dimensional(3D) object are assigned to RGB multiple bit planes according to their RGB gradation levels. The RGB multiple bit planes are sequentially displayed in a time-division-multiplexed manner. Consequently, the proposed method yields a color gradation representation of a reconstructed 3D object.     

多通道光谱采集系统滤光片设计方法研究

普通彩色相机加载宽带滤光片构造的多通道光谱采集系统的光谱重建性能与滤光片的选用密切相关。针对上述问题,提出基于主成分分析法的合成滤光片设计方法,旨在获得具有较高光谱重建性能并对所有图像场景均适用的最优滤光片组合。在收集多个宽带滤光片的基础上,测得其透射率并转换成矩阵形式;采用主成分分析方法提取该矩阵的前2个主成分,标准化处理后的主成分即为所求合成滤光片的透射率。为了验证上述方法获得的滤光片的性能,利用色差和光谱均方根误差2个指标对加载了合成滤光片的仿真采集系统的光谱重建精度进行了评价。实验结果表明:采用该方法得到的滤光片组合优于常用方法得到的滤光片组合, 用其构造的成像系统具有较高的色度重建精度和光谱重建精度,此外,改变目标场景颜色特性,其重建性能保持稳定。     

Color fusion of SAR and FLIR images using a natural color transfer technique

Fusion of synthetic aperture radar (SAR) and forward looking infrared (FLIR) images is an important subject for aerospace and sensor surveillance. This paper presents a scheme to achieve a natural color image based on the contours feature of SAR and the target region feature of FLIR so that the overall scene recognition and situational awareness can be improved. The SAR and FLIR images are first decomposed into steerable pyramids, and the contour maps in the SAR image and the region maps in the FLIR image are calculated. The contour and region features are fused at each level of the steerable pyramids. A color image is then formed by transferring daytime color to the monochromic image by using the natural color transfer technique. Experimental results show that the proposed method is effective in providing a color fusion of SAR and FLIR images.     

Color adjustment algorithm adapted to the spectral reflectance estimation method

We are developing a daily health monitoring system that uses mobile phones with cameras and analyzes physiological conditions from R, G, and B intensity levels. However, since it is affected by various imaging conditions of the image input, color correction is required for accurate health monitoring. Therefore, we developed and validated a colorcorrection algorithm to derive reliable color information by correcting the spectral reflectance using the Wiener estimation and a color chart.     

Taylor-series method for two-nucleon transfer form factors

A new method is developed for transforming the infinite or finite well two-nucleon wave functions from individual coordinates to relative and c.m. coordinates by expanding two-nucleon wave functions around the c.m. of the system. Finite size corrections to the point approximation of the two-nucleon transfer form factors with harmonic oscillator and Woods-Saxon single particle functions are computed and compared with the results obtained using other methods.     

Improvement in appearance of colors for elderly persons using lightness transform

The color of an object appears to be different for elderly and young persons. This is because human visual features vary with on age. In general, the spectral transmittance of the crystalline lens of an elderly person is lower than that of a young person. The low spectral transmittance decreases the brightness of the visual field. This phenomenon affects the color appearance of an image in human visual perception. In this paper, a lightness transform method is proposed to improve the color appearance of images for elderly persons. In the proposed method, colors that are difficult for an elderly person to see are transformed into colors that are easy to see by adding lightness contrast. The performance of the proposed method is confirmed in experiments using digital images.     

Variational method for solving radiative transfer problems

The variational principle is used to solve two problems of radiative transfer. The first one is the temperature distribution and radiative heat flux for a plane layer of ceramic material. While the second is the calculation of the integral blankness degree of a sphere filled with dust of an arc steel-melting furnace. Numerical results obtained shows good agreement with the published data.     

The multiband method in radiative transfer calculations

The multiband method is developed for use in radiative transfer problems. The essence of the method is to divide the frequency range into both energy groups and cross section bands. Included in the formulation are the effects of continuously varying (in space and time) opacities, which leads to band-to-band streaming transfer terms. Several numerical examples indicate the increased accuracy possible by using a combination of groups and bands, as contrasted to groups alone.