Three-dimensional color particle image velocimetry based on a cross-correlation and optical flow method

Rainbow particle image velocimetry(PIV)can restore the three-dimensional velocity field of particles with a single camera;however,it requires a relatively long time to complete the reconstruction.This paper proposes a hybrid algorithm that combines the fast Fourier transform(FFT)based co-correlation algorithm and the Horn–Schunck(HS)optical flow pyramid iterative algorithm to increase the reconstruction speed.The Rankine vortex simulation experiment was performed,in which the particle velocity field was reconstructed using the proposed algorithm and the rainbow PIV method.The average endpoint error and average angular error of the proposed algorithm were roughly the same as those of the rainbow PIV algorithm;nevertheless,the reconstruction time was 20%shorter.Furthermore,the effect of velocity magnitude and particle density on the reconstruction results was analyzed.In the end,the performance of the proposed algorithm was verified using real experimental single-vortex and double-vortex datasets,from which a similar particle velocity field was obtained compared with the rainbow PIV algorithm.The results show that the reconstruction speed of the proposed hybrid algorithm is approximately 25%faster than that of the rainbow PIV algorithm.

Is the Two-Color Method Superior to Empirical Equations in Refractive Index Compensation?

The Edlén empirical equations and the two-color method are the commonly used approaches to converting a length measured in air to the corresponding length in vacuum to eliminate the influence of the refractive index of air. However, it is not well known whether the two-color method is superior to empirical equations in refractive index compensation. We investigated the uncertainties of these approaches via numerical calculations of their sensitivity coefficients of environmental parameters. On the basis of a comparison of their uncertainties, we found that in a 0% humidity environment, the two-color method had potential to provide greater measurement accuracy than the empirical equations.

Methods for translating color terms

The cultural differences are reflected not only in literature,arts,thought etc,but also in something inconspicuous,such as the usage of color terms.

Total phenolic, flavonoid content, and antioxidant activity of flour, noodles, and steamed bread made from different colored wheat grains by three milling methods

The objective of this study was to evaluate the effects of wheat variety, food processing, and milling method on antioxidant properties. Black wheat variety Heibaoshi 1 had the highest total phenolic content(659.8 μg gallic acid equivalents g-1), total flavonoid content(319.3 μg rutin equivalents g-1), and antioxidant activity, whereas light purple wheat variety Shandongzimai 1 had the lowest total flavonoid content(236.2 μg rutin equivalents g-1) and antioxidant activity. Whole wheat flour and partially debranned grain flour had significantly higher total phenolic contents, total flavonoid contents, and antioxidant activity than refined flour(P < 0.05). Compared with flour, total phenolic contents, total flavonoid contents and antioxidant activity decreased in noodles and steamed bread, whereas noodles had slightly higher total phenolic and flavonoid content than steamed bread. Antioxidant activities(by ferric reducing ability of plasma assay) of steamed bread made from whole wheat flour, partially debranned grain flour, and refined flour were 23.5%, 21.1%, and 31.6% lower, respectively, than the corresponding values of flour. These results suggested that black whole wheat flour and partially debranned grain flour are beneficial to human health.

SOLVING COLORED YANG-BAXTER EQUATION BY WU’S METHOD

In this article, we discuss nonsymmetric solutions of the colored Yang-Baxter equation dependent on spectral as well as colored parameters and give all seven-vertex solutions by Wu＇s method. It is also proved that the solutions are composed of six groups of basic solutions up to five solution transformations. Moreover, al l solutions can be classified into two categories called Baxter type and free-fermion type.

Technology of black coloring for stainless steel by electrochemical method

The technology of black coloring for stainless steel by electrochemical method was studied. The optimum bath compositions and operating conditions were obtained as follows: 4050g/L K2Cr2O7 , 1520g/L MnSO4, 1520g/L （NH4）2SO4, 2040g/L H3BO3, 2030 g/L additive A, 2 g/L （NH4）6Mo7O 24 ; time 920 min; temperature 1530℃; potential 3V and current density 12mA/cm 2 . The effects of the compositions of the bath on the quality of black colored film were discussed. The influences of passivation process on the black coloring velocity and performances of black colored film layer were investigated. The results show that the passivation process can improve the corrosion resistance and the stability to bear color-change; （NH4）2SO4 can control the black coloring velocity and prolong black coloring bath life remarkably; and additive A can improve the evenness and compactness of black colored film layer. The results of scanning electron microscopy and energy dispersive spectra show that the microstructure is of cylindrical lump, the filling process can decrease the crackles, and the main elements of black colored film are Fe, Cr, Mn and Ni.

Temperature Field Reconstruction in High-Temperature Gas by Using the Colored Background Oriented Schlieren Method

A 3D temperature field reconstruction method using the colored background oriented schlieren(CBOS)method is proposed to address image blurring due to the different refractive index of the multi-wavelength light and significant errors produced when the traditional background oriented schlieren(BOS)method is applied to high-temperature gas.First,the traditional method is employed to reconstruct the non-uniform 3D temperature field.Second,the CBOS method is applied to correct the distortion.Then,by analyzing the correlation coefficient among different color points of the colored background pattern,the non-uniform temperature field is reconstructed much more accurately.Finally,the experimental results are verified by applying the Runge-Kutta ray-tracing method and the thermocouple contact measurement method.The maximum average temperature error of the CBOS-reconstructed temperature field is 12.92°C,compared with the thermocouples.Therefore,an accurate three-dimensional reconstruction of the temperature field can be achieved by the proposed method effectively.

Real- Time Color Enhancement Method Used for Intelligent Mobile Terminals

In certain environments and under some conditions, the video images taken by the intelligent mobile video phones seem dark, and the colors are not bright or saturated enough.This paper presents an adaptive method to enhance the video image brightness visualization and the color performance depending on the certain hardware property and function parameters. The experimental results prove that this method can enhance the colors and the contrast of the video images, based on the estimated quality feature values of each frame, without using the extra Digital Signal Processor (DSP).

False Color Method for Retinal Oximetry

Oximetry is a method for measuring the oxygen saturation of haemoglobin in blood. Particularly, retinal oximetry based in the measurement of oxygen saturation in retinal vessels has acquired great interest to gather information on blood oxygenation from said vessels within inner and outer retina. Non-invasive spectrophotometric retinal oximetry has been studied for over five decades based on imaging spectroscopy. However, Optical Coherence Tomography (OCT) is an alternative to analyze the absorption difference between oxyhaemoglobin (HbO2) and deoxyhaemoglobin (Hb) in the retinal vessels and the choroidal structure. We propose in this paper an alternative process to manipulate conventional OCT images to evaluate changes in the relative haemoglobin oxygen saturation. Conventional OCT images from 570 nm and 600 nm in gray scale are converted to a corresponding color scale to be compared to the oxygenation information involved in the original gray scale OCT images.

基于分数阶全变分和低秩正则化的彩色图像去模糊方法

针对现有的彩色图像去模糊过程中存在色彩失衡、阶梯效应和伪影等现象,提出了一种基于分数阶全变分和低秩正则的图像去模糊优化方法。首先,将传统的RGB彩色图像转换到YCbCr颜色空间,利用其亮度通道特征解决色彩失衡问题;其次,利用分数阶全变分的特征消除图像恢复任务中出现的阶梯效应,并且引入加权核范数低秩正则进一步抑制伪影及噪声;最后,利用交替方向乘子法设计出高效的求解方法,通过迭代优化得到纯净图像的最优估计。对彩色图像测试的实验结果表明,所提出的方法对图像去模糊任务取得较好的视觉恢复效果,客观评价指标良好。

3种不同熟化方式对彩色马铃薯挥发性风味物质组成的影响

采用气相色谱-离子迁移谱联用仪(GC-IMS)分析在不同熟化方式下彩色马铃薯的挥发性风味物质组成。结果表明:从3种不同熟化方式的彩色马铃薯样品中定性鉴定出挥发性有机物质共有52种,其中醛类物质的种类和相对含量均最高,表明醛类物质对马铃薯香味的呈现起主要作用。不同熟化方式对彩色马铃薯挥发性物质的组成及含量存在一定的差异,且不同颜色的马铃薯在同一种熟化方式下,其挥发性物质含量也表现出差异。在蒸制的彩色马铃薯中挥发性风味物质含量较低,在烤制和油炸的彩色马铃薯中风味物质含量较高。挥发性成分的种类和含量可以作为区分彩色马铃薯不同熟化方式的重要特征指标。

不同干燥方式对柠檬片品质的影响

该研究旨在探究不同干燥方式对贮藏期柠檬片品质的影响。分别采用真空冷冻干燥(vacuum freeze drying,VFD)、热风干燥(hot air drying,HAD)、微波干燥(microwave drying,MD)3种方式加工制备柠檬片,并研究了3种干燥方式对柠檬片色泽、基础品质、营养物质和风味的影响。结果表明,柠檬片经过真空冷冻干燥、热风干燥、微波干燥不同干燥处理后品质与风味不同。冻干组柠檬片具有较小的收缩率(11.65%),较高的复水比(5.14)、亮度值(48.6)和V_(C)含量(3.13 mg/g DW),电子鼻各传感器的响应值较高,即其色泽、品质、风味都优于热风干燥与微波干燥方式。因此,使用冻干工艺可以保证品质。

典型场景彩色夜视融合图像质量主观评价实验

评价特定场景下红外和可见光(微光)彩色融合图像质量的研究对彩色夜视融合技术和嵌入式系统开发具有重要作用。由于主观评价实验能够得到与人眼感受一致的评价结果因而成为研究的热点。因此,该文针对海天、森林、城镇、乡村和特殊条件五个典型应用场景,提出基于动态参考的多刺激比较主观评价法,开展了大规模典型场景彩色融合图像主观评价实验,建立了包含1648幅彩色融合图像的质量主观评价数据库;此外,提出基于评价实验特性的模糊综合评判方法用于分析不同融合算法的场景适用性。实验数据一致性分析中,该主观评价法具有较高的皮尔逊相关系数,表明本文构建的数据集具有良好的有效性与可靠性。该文结果可为进一步开展夜视融合图像质量评价研究提供实验基础和理论依据。

基于鲜切苹果保鲜的可食性复合保鲜膜配方优化

以海藻酸钠、羧甲基纤维素钠、壳聚糖为主要原料制备可食性复合保鲜膜。由单因素实验制得复合膜,根据复合膜的性能及其对鲜切苹果的保鲜效果获得最优的单因素。在此基础上,应用响应面法优化复合膜的工艺组合并验证其保鲜效果。结果表明,经响应面法优化后的复合膜主要原料配方为:壳聚糖添加量0.98 g,海藻酸钠添加量1.55 g,羧甲基纤维素钠添加量1.31 g。应用该复合保鲜膜进行鲜切苹果保鲜,得到处理样品的色差a值5.95、DPPH自由基清除率35.27%、ABTS自由基清除率34.43%,而对照样品的a值9.10、DPPH自由基清除率21.31%、ABTS自由基清除率27.62%。该可食性复合保鲜膜具有良好的保鲜效果,为生态复合保鲜膜的研发与果蔬保鲜提供参考。

基于双参考优化的壁画图像色彩还原

褪变色壁画图像的色彩还原研究可以促进壁画的保护和展示。壁画图像色彩还原旨在将退化壁画图像的色彩褪变区域还原为原有色彩。常规的基于单幅参考壁画图像的色彩还原方法难以选取与退化壁画图像相似的参考壁画图像,进而影响色彩还原质量。为此,提出一种基于双参考优化的壁画图像色彩还原方法。采用双参考策略,即使用2幅参考壁画图像对退化壁画图像进行色彩还原,利用图像优化模块抑制褪变色壁画图像中普遍存在的噪声、划痕等多重退化,通过编码器-解码器网络编码提取壁画图像多尺度特征,并构建特征融合模块优化壁画图像的多尺度特征。采用双参考指导模块计算参考壁画图像与退化壁画图像的语义对应置信度,以实现图像区域间的相似性匹配,并实现2幅参考壁画图像的风格融合。在此基础上,利用融合特征实现退化壁画图像的色彩还原。实验结果表明,该方法可以较准确地还原退化壁画图像色彩,同时能较好保持壁画图像原有的边缘结构信息,并且使用无参考图像质量评估指标对各个方法的还原壁画图像进行客观评估,与对比方法相比,该方法在客观评估指标上最多可降低12.2%。

儿童校园建筑色彩设计综述

校园是儿童学习、生活的重要场所,其环境对儿童起着培养、引导的作用。色彩作为建筑环境的重要构成要素,其选择与设计直接关系到儿童的教育与成长。文章从儿童校园建筑色彩对儿童心理、生理产生的影响出发,对儿童校园建筑色彩设计研究的理论基础进行了梳理和分析,进而从不同角度总结概括了儿童校园建筑色彩的设计原则与设计策略。最后对儿童校园建筑色彩设计的实践过程进行了总结,并对其未来发展方向提出了展望,旨在为儿童校园建筑色彩设计方法研究提供参考。

基于语义分析法的城市街景色彩感知评价与优化研究

为探究使用者对哈尔滨市中央大街现状色彩的感知评价情况,该文运用语义分析法这一采用“语言”方式对公众进行心理测评的定量分析工具,结合街景图像、色卡软件、数理分析软件作为记录和分析色彩样本的基础工具对其开展问卷调查与研究。研究结果表明,受访者对中央大街街区的街景色彩总体持正面评价,对色彩视觉感知体验更好,空间感知体验最差,对经过系统色彩设计、风格鲜明的街道评价更高。依据以上结果,从总体色彩构成、一般街道品质提升和空间感知强化等方面提出了街景色彩优化策略。

仿生结构生色技术及其在纺织领域应用的研究进展

针对传统印染行业高能耗、高污染的问题,急需革新染色技术,开发具有更加高效、节能和环保的染色新方法。结构色因其色彩饱和度高、色彩长期稳定且对环境友好而受到了越来越多的关注,并取得了极大进展,尤其是在纺织印染领域。首先分析了结构色的形成原理,系统总结了结构色材料的制备新技术,包括刮涂法/喷涂法、垂直沉积法、重力沉降法、浸渍提拉法、层层自组装法、电泳沉积法、静电纺丝法、磁控溅射法、原子层沉积法等,并比较了各种技术的优劣。在此基础上,进一步探讨了结构色在纺织领域中的多维应用,指出了结构色所面临的挑战,并从仿生自然发展新型结构色材料、提高结构色色彩丰富度及力学稳定性、突破结构色规模化制备技术、完善结构色产品生态等4个方面展望了结构色的未来发展方向,以期推动结构色跨越式发展,助力“碳达峰,碳中和”国家战略。

颗粒图像的颜色校准与表征

【目的】减少图像法测量系统中颗粒成像的颜色失真,并对颗粒进行颜色表征。【方法】采用色卡对颗粒成像系统进行标定,使用色彩校正算法建立实际拍摄的色卡的颜色值与D65光源下的色卡理论颜色值之间的映射关系,以此对颗粒图像进行色彩校正,对比分析基于多项式回归的6种色彩校正算法,对基于校正前、后色卡的平均色差和算法的曝光适应性进行算法测试,并在白色LED灯光与偏黄的卤素灯光照射下分别验证色彩校正效果。【结果】三阶多项式色彩校正算法的回归精度最高,在白色LED光源照射下,校正前、后色卡的24个色块的平均色差由38.67下降到3.82,但测试发现,三阶多项式色彩校正算法不具备曝光适应性;三阶根多项式色彩校正算法在回归精度上接近三阶多项式色彩校正算法且具有良好的曝光适应性。【结论】基于色卡标定和色彩校正算法可以在一定程度下减少系统的颗粒成像的色偏,在6种校正算法中三阶根多项式色彩校正算法能够提高回归精度和曝光适应性;针对颗粒系,可结合颗粒的平均色品坐标和颗粒数量进行表征,针对单个颗粒,可以使用颜色矩和主要颜色进行表征。

光子晶体结构生色真丝织物的制备及应用研究

为实现真丝织物的结构生色,文章分别利用真空辅助过滤法和手绘法在白色真丝织物上构筑光子晶体结构。进一步探究真空辅助过滤法中微球组装液体积浓度对结构色的影响规律,分析微球在真丝织物上形成光子晶体运动机制,讨论真丝织物上光子晶体结构色的虹彩效应,并探究手绘法在真丝织物光子晶体结构生色中的应用效果。结果表明:真空辅助过滤法中聚(苯乙烯-甲基丙烯酸),即P(St-MAA)微球组装液的体积浓度为2.4 L/m^(2)时,真丝织物的两面能同时获得光子晶体结构色,此时正反面结构色的反射率峰值在18%左右;在真空辅助过滤法中,P(St-MAA)微球在真丝织物上形成光子晶体结构的过程遵循“先反后正”堆积原则,即织物反面先形成光子晶体,随后微球进一步透过织物堆积在正面。此外,该光子晶体结构生色真丝织物的虹彩效应不明显,与常规染料或颜料着色效果接近;手绘法可以获得图案化的光子晶体生色结构,较适合于个性化加工。该研究为光子晶体结构生色在真丝织物着色中的应用提供参考。