基于Shape-from-Shading的月球表面三维形状恢复算法研究

提出了一种基于Shape-from-Shading的月球表面三维形状恢复算法。首先分析了在太阳光照射下月球表面成像模型,建立了使用Lommel-Seeliger反射模型描述的反射图方程。然后用有限差分近似微分运算,将反射图方程所示的一阶变系数线性偏微分方程进行离散化处理,得到关于表面高度函数的代数方程。进而采用超松弛迭代法进行求解,获得月球表面三维高度函数值。最后使用合成图像和实际月球图像进行三维形状恢复仿真实验。实验结果表明提出的算法可以有效地恢复月球表面三维形状。

一种基于混合反射模型的Shape-From-Shading直接算法

提出了一种基于混合反射模型的Shape-From-Shading直接算法。使用接近实际的混合反射模型描述的反射图方程作为求解对象,用有限差分近似微分运算,将反射图方程离散化,得到所求高度函数满足的代数方程,进而用迭代算法计算出表面高度。最后,用以合成图像和实际图像的三维形状恢复实验说明提出算法的有效性。

Quantifying foliar trait variation and covariation in sun and shade leaves using leaf spectroscopy in eastern North America

Characterizing foliar trait variation in sun and shade leaves can provide insights into inter-and intra-species resource use strategies and plant response to environmental change.However,datasets with records of multiple foliar traits from the same individual and including shade leaves are sparse,which limits our ability to investigate trait-trait,trait-environment relationships and trait coordination in both sun and shade leaves.We presented a comprehensive dataset of 15 foliar traits from sun and shade leaves sampled with leaf spectroscopy,including 424 individuals of 110 plant species from 19 sites across eastern North America.We investigated trait variation,covariation,scaling relationships with leaf mass,and the effects of environment,canopy position,and taxonomy on trait expression.Generally,sun leaves had higher leaf mass per area,nonstructural carbohydrates and total phenolics,lower mass-based chlorophyll a+b,carotenoids,phosphorus,and potassium,but exhibited species-specific characteristics.Covariation between sun and shade leaf traits,and trait-environment relationships were overall consistent across species.The main dimensions of foliar trait variation in seed plants were revealed including leaf economics traits,photosynthetic pigments,defense,and structural traits.Taxonomy and canopy position collectively explained most of the foliar trait variation.This study highlights the importance of including intra-individual and intra-specific trait variation to improve our understanding of ecosystem functions.Our findings have implications for efficient field sampling,and trait mapping with remote sensing.

Degree of shade tolerance shapes seasonality of chlorophyll, nitrogen and phosphorus levels of trees and herbs in a temperate deciduous forest

Forest productivity is closely linked to seasonal variations and vertical differentiation in leaf traits.However,leaf structural and chemical traits variation among co-existing species,and plant functional types within the canopy are poorly quantified.In this study,the seasonality of leaf chlorophyll,nitrogen(N),and phosphorus(P)were quantified vertically along the canopy of four major tree species and two types of herbs in a temperate deciduous forest.The role of shade tolerance in shaping the seasonal variation and vertical differentiation was examined.During the entire season,chlorophyll content showed a distinct asymmetric unimodal pattern for all species,with greater chlorophyll levels in autumn than in spring,and the timing of peak chlorophyll per leaf area gradually decreased as shade tolerance increased.Chlorophyll a:b ratios gradually decreased with increasing shade tolerance.Leaf N and P contents sharply declined during leaf expansion,remained steady in the mature stage and decreased again during leaf senescence.Over the seasons,the lower canopy layer had significantly higher chlorophyll per leaf mass but not chlorophyll per leaf area than the upper canopy layer regardless of degree of shade tolerance.However,N and P per leaf area of intermediate shade-tolerant and fully shade-tolerant tree species were significantly higher in the upper canopy than in the lower.Seasonal variations in N:P ratios suggest changes in N or P limitation.These findings indicate that shade tolerance is a key feature shaping inter-specific differences in leaf chlorophyll,N,and P contents as well as their seasonality in temperate deciduous forests,which have significant implications for modeling leaf photosynthesis and ecosystem production.

Evaluation of the Effect of Four Levels of Shade on the Growth and Development of Desmodium adscendens with a View to Its Domestication as a Cover Crop in Côte d’Ivoire

Desmodium adscendens is a plant in the Fabaceae family that is very important to man, both agronomically and medicinally. It is an important cover crop that contributes to improving soil fertility, reducing the risks associated with crop pests and weeds. However, very little research has been carried out into its domestication for use as a cover crop in banana plantations in Côte d’Ivoire. The general objective of this study was to evaluate, under semi-controlled conditions, the effect of different levels of shade on the growth and development of Desmodium adscendens. The studies were carried out on the experimental site of the UP-Plant Physiology Laboratory. Four shading levels were evaluated: 0 (NO), 20% (N1), 40% (N2) and 60% (N3) light levels. The Desmodium adscendens cuttings used were collected from a 3-month nursery. For each treatment, 10 tubs containing sterilized soil were used, and 50 cuttings were planted. After planting, growth and development parameters were assessed weekly on 10 plants. In addition, yield and fresh and dry mass were measured. Finally, the reproductive cycle of Desmodium adscendens was determined. The results showed that plant growth and development were greatest in plants grown under the 40% shade level, followed by the 20% and 60% shade levels. In contrast, plants in full light showed poor growth and development. The 40% shade level was the most favorable for growing Desmodium adscendens cuttings, with a cycle length of 67 days. Growing Desmodium adscendens under shade with 20% and 40% light levels could be recommended to farmers.

Probabilistic Global Maximum Power Point Tracking Algorithm for Continuously Varying Partial Shading Conditions on Autonomous PV Systems

A photovoltaic (PV) string with multiple modules with bypass diodes frequently deployed on a variety of autonomous PV systems may present multiple power peaks under uneven shading. For optimal solar harvesting, there is a need for a control schema to force the PV string to operate at global maximum power point (GMPP). While a lot of tracking methods have been proposed in the literature, they are usually complex and do not fully take advantage of the available characteristics of the PV array. This work highlights how the voltage at operating point and the forward voltage of the bypass diode are considered to design a global maximum power point tracking (GMPPT) algorithm with a very limited global search phase called Fast GMPPT. This algorithm successfully tracks GMPP between 94% and 98% of the time under a theoretical evaluation. It is then compared against Perturb and Observe, Deterministic Particle Swarm Optimization, and Grey Wolf Optimization under a sequence of irradiance steps as well as a power-over-voltage characteristics profile that mimics the electrical characteristics of a PV string under varying partial shading conditions. Overall, the simulation with the sequence of irradiance steps shows that while Fast GMPPT does not have the best convergence time, it has an excellent convergence rate as well as causes the least amount of power loss during the global search phase. Experimental test under varying partial shading conditions shows that while the GMPPT proposal is simple and lightweight, it is very performant under a wide range of dynamically varying partial shading conditions and boasts the best energy efficiency (94.74%) out of the 4 tested algorithms.

Photoinhibition in Shaded Cotton Leaves After Exposing to High Light and the Time Course of Its Restoration

Chlorophyll fluorescence emission, pigment composition and photosynthetic rate of shade-grown cotton ( Gossypium hirsutum L.) plants were measured immediately after suddenly exposing to full sunlight and at regular intervals there after within 15 d. Photoinhibition occurred in shade-grown cotton leaves immediately after exposed to full sunlight. The chlorophyll fluorescence parameter F-v/F-m and PhiPS II, which reflect the efficiency of PS II,obviously decreased in shade-grown leaves, much lower than that of the full sunlight-grown leaves. On the contrary, F-o value was sharply increased. Neither of these parameters could completely recover till next morning. The photoinhibition was chronic and continued for about 4 d, while the F-v/F-m and the net photosynthetic rate ( P-n) continued to decline, then began to increase gradually 6 d later and turned stable after 10 - 12 d, appearing as an acclimation phenomenon. However, the final value of F-v/F-m and P-n did not reach the level as in those leaves grown in the full sunlight ever before. The final P-n was higher by 60% than that before exposure, but lower for more than 40% than that of the full sunlight-grown leaves. The most notable response of chloroplast pigment composition was a pronounced increase in the pool size of carotenoids in xanthophyll cycle over a period of 3 d. The results indicated that when shade-grown cotton seedlings were suddenly transferred to the full sunlight, the decline of F-v/F-m and P-n might associate with the damage of the PS II reaction center. During the light acclimation, photoprotective mechanisms such as the xanthophyll cycle-dependent energy dissipation were increased, so that photodamage in leaves transferred from low to high light might be reduced.

Physiological Basis of Photosynthetic Tolerance to Photooxidation and Shading in Rice

Thirty genotypes from rice germplasm were identified under photooxidation and shading condition and divided into four basic types : (1) cultivars tolerant to both photooxidation and shading, (2) cultivars tolerant to photooxidation but sensitive to shading, (3) cultivars tolerant to shading but sensitive to photooxidation, and (4) cultivars sensitive to photooxidation and shading. A comparative study of photosynthetic characteristics of a cultivar (cv. Wuyujing 3) that is tolerant and a cultivar (cv. Xiangxian) that is sensitive to both photoinhibition and shading showed that the photochemical efficiency of PSⅡ ( F v/F m ) and the content of PSⅡ_D1 protein in the tolerant cultivar “Wuyujing 3” decreased less under photoinhibition conditions as compared with “Xiangxian”. Under photooxidation conditions, superoxide dismutase was induced rapidly to a higher level and the active oxygen O - built up to a lower level in “Wuyujing 3” than in “Xiangxian”. At the same time, the photosynthetic rate decreased by 23% in “Wuyujing 3” vs. 64% in “Xiangxian”. Shading (20% natural light) during the booting stage caused only small decreases (7%-13%) in RuBisCO activity and the photosynthetic rate in “Wuyujing 3” but showed marked decreases (57%-64%) in “Xiangxian” which corresponded to the decreases in grain yield in the two cultivars (38% and 73%, respectively). The correlation analysis showed that the tolerance to photooxidation is mainly related to PSⅡ_D1 and that to shading is mainly related to RuBisCO activity. This study provided a simple and effective screening method and physiological basis for crop breeding in enhancing tolerance to both high and low radiation.

X-Rite’s ShadeVision System与Vitapan Classical比色板的匹配性分析

目的X-Rite’sShadeVision System和Vitapan Classical比色板的匹配性。方法采用X-Rite’sShadeVision System对Vitapan Classical比色板进行测色。结果X-Rite’s ShadeVision System测量结果排序与原排序一致,排列差异最大有6个色片的差距。相邻比色板的色差ΔEab参差不齐,最大的色差6.92,而最小的色差只有1.21。结论X-Rite’s ShadeVision System与Vitapan Classical比色板不完全匹配。

Effects of Shading Treatment on the Growth of Bischofia javanica Seedlings

With annual Bischofia javanica seedlings as experimental material, the plasticity and comprehensive evaluation methods were employed to investigate the effects of different shading degrees （100% NS （natural sunshine）, 41.3% NS, 14.6% NS and 3.6% NS） on B. javanica seedlings growth, so as to obtain the shade toler- ance in B. javanica. The results showed that with the shading degree increasing, the seedling height increment, diameter increment, leaf area, fresh weights （above- ground part, underground part and whole plant） and dry weights （aboveground part, underground part and whole plant） of B. javanica seedlings all increased first and then decreased, and reached peak values under 41.3% NS, while the total root length, average root diameter, total surface area, total root volume and total root number all presented a decreasing trend. Also the comprehensive evaluation by subordinate function value method and plasticity analysis were carried out on these growth indexes. It was concluded that B. javanica seedlings have medium shade tol- erance from the comDrehensive analysis of growth indexes.

Shadepilot全牙比色仪测定牙龈色对比色板色标颜色的影响

目的:通过体外模拟实验评价牙龈比色板在临床比色中的意义。方法:使用分光光度计型全牙比色仪Shadepilot测量42个比色板色标在4种牙龈比色板(Gumy1,2,3,4)衬托下颈、中、切3部分色彩参数(CIE1976L*a*b*),使用比色仪内置软件计算有无牙龈比色板衬托的色标相同位置的色差值(△E),分析牙龈色对色标颜色的影响。结果:42个色标在4种牙龈色衬托下与无牙龈色衬托的色差值为:颈部(2.93±0.79)NBS,中部(0.51±0.27)NBS,切端(0.61±0.29)NBS;Gumy-1、2、3、4组牙龈色对色标颈、中、切三部分的影响组间差异无显著性(P>0.05)。结论:在模拟测量条件下,牙龈色对比色板色标颈部有影响,肉眼可识别,对色标中部及切端无影响;4种模拟牙龈颜色对比色板色标颜色的影响无统计学差异。

Effects of Shading Degree on Storage Rate and Growth of Phoebe bournei Seedlings in Fields

In the research, four shading treatments were set, including the treatments with shading degrees at 0, 40%, 60% and 70%, in order to explore storage rate and seedling growth of annual Phoebe bournei. The results showed that the storage rate is growing upon shading degree. In the research, for example, storage rate reached the peak with the shading degree at 70%, and only 42.2% with shading degree at 0. In addition, seedling height and ground diameter showed extremely significant differences among treatments, and the treatment with shading degree at 60% was the best.

基于Shape from Shading的医学图像三维重建

通过对由医疗成像设备获取的二维灰度图像进行形状重建,得到的三维立体原型能帮助医学诊断人员确诊病情。介绍了Shape from Shading的实现原理和扫描电镜成像系统的简单构成,提出了一种基于线性逼近的用于解决SEM反射映射函数的实现方法,并将之应用于红血细胞的三维图像重构,得到的细胞图形非常接近其真实形状。

不同遮阴条件对北美冬青幼苗叶片光合特性与超微结构的影响

研究不同遮阴条件下北美冬青(Ilex verticillata)幼苗叶片的光合生理特性与超微结构,揭示其对光的适应规律、光合与超微结构关系,为北美冬青引种栽培、苗木培育和经营提供依据。以3 a生北美冬青实生苗为研究对象,采用Li-6800光合仪测定全光(L_(0))、35%遮阴(L_(35))、55%遮阴(L_(55))和75%遮阴(L_(75))4种遮阴条件下北美冬青幼苗叶片的光合指标、叶绿素荧光,利用扫描电镜观察北美冬青叶片超微结构。结果表明:7月4种处理净光合速率日变化曲线呈单峰;北美冬青幼苗叶片35%遮阴处理光响应表现最佳。随着遮阴度的提高,光适应下的初始荧光(F_o)、最大荧光(F′_(m))、最大可变荧光(F′_(v))、PSⅡ光能转换效率(F′_(v)/F′_(m))、稳态荧光(F_(S))和光化学淬灭系数(q_(P))呈逐渐变大趋势;北美冬青幼苗叶片的非光化学淬灭系数(Q_(NP))随遮阴度提高而降低,叶片在受到强光胁迫时通过耗散热能来缓解光合损伤,具有较高的光保护能力。北美冬青幼苗叶片气孔张开度随光强的提高而变大,但过强的光照会抑制气孔张开。净光合速率随气孔的大小及张开度而变化,气孔张开度最大时,净光合速率最大。

不同角度对X-Rite’s Shade Vision系统测量结果的影响

目的观察不同角度对X-Rite’s ShadeVision系统测量比色板结果的影响。方法将一副新的Vita16色比色板固定在粉红色的蜡中。X-Rite’s ShadeVision系统分别在平行于比色板唇面,5°、10°、15°向左右侧和切向、龈向倾斜时测量颜色,以L*,a*,b*及Vita16色比色板色片颜色表示测量结果。计算ΔL,Δa,Δb和ΔE*ab,数据用单因素方差分析。结果向右倾斜5°、10°、15°时L*值分别减少0.22,0.97和0.93,而向左倾斜L*增加;垂直向角度改变时,L*值增加;最大的ΔL值在向龈向倾斜15°(2.84)和向切向倾斜15°(2.37),这导致相应位置出现最大的ΔE*ab(3.22±0.37)和(2.50±0.63),15°向左和右倾斜时,ΔE*ab分别为1.87±0.59和1.20±0.25。与其他位置比较,向龈向和切向15°时,ΔE*ab明显高(P<0.05)。结论X-Rite’sShadeVision测量时,正确的测量位置对获得准确的测量结果非常重要,角度的偏移,尤其是垂直向的倾斜会影响测量结果。

基于图象空间分布的Shading算法

本文首先介绍了基于局部光照模型的串行Shading算法，然后对设计分布式Shading算法所用到的动态任务分配、数据适应性任务分配、任务粒度等因素作了较为详细的论述，并给出了所设计的新的数据适应性任务划分算法，最后给出了所设计的分布式Shading算法的描述和实验结果.

共享数据工程(SHADE)体系结构及实现描述

文章在深入研究DIICOE的基础上,描述了DIICOE中共享数据工程(SHADE)的体系结构及实现方式。

Shade-eye-EX测量颜色时稳定性研究

目的 :研究用松风 Shade- eye- EX电脑比色仪测量比色板颜色时的稳定性。方法 :用松风 Shade- eye- EX电脑比色仪测量 Vintage Halo(松风 )、VITA及 Vita 3D- master比色板的每个比色片 ,每片测量 9次 ,分别用松风 Shade- eye- EX自然牙及瓷牙测量模式测量 ,3人次每人重复完成一次。结果 :(1)瓷牙测量模式测量时 ,Shade- eye- EX对 Vita 3D- master、VITA及 Vintage Halo(松风 )比色板测量结果绝大多数表现为同一数字结果。(2 )测量比色板时 Shade- eye- EX应用瓷牙测量模式较自然牙测量模式准确率高。(3)在两种模式测量比色板下 ,同一次测量的三次按键时 ,测量头位置保持不动 ,结果显示数字的同一性较高 ;测量头位置每次都动时 ,结果显示数字变动性较大 ;(4)无论采取任何方式 ,三种比色板的结果总会有一些结果显示不同。结论 :松风 Shade- eye- EX电脑比色仪测量颜色时 ,测量模式与需测量对象相符 ,否则 ,结果会有很大的差异 。

A study on the shade tolerance of Muehlewbeckia complera

Muehlewbeckia complera was introduced to China in 2002 as indoor-hanging ornamental foliage plant. The experiment of the shade tolerance for this species was carried out in different light intensities (0.14–946.00 μmol·m?2·s?1). After 40 days in experimental areas, leaf photosynthentic characteristics indexes ofM. complera in different photosynthesis active radiation (PAR) were measured with LI-COR6400 apparatus, such as the light compensation point, light saturation point, and maximum net photosynthesis rate, at the same time, the increments of total leaf area and leaf amount were measured. The results showed that the optimum light intensity range forM. complera was from 9.26 μmol·m?2·s?1 to 569.00 μmol·m?2·s?1 (463–28150 lx, relative humidity (RH) for 46–60%, temperature at 16–22°C). Under this condition, leaf photosynthetic efficiency was tiptop. AlthoughM. complera belonged to the moderate sun-adaptation plant species, the plant growth was inhibited when PAR increased to the level of 569.000 μmol·m?2·s?1 or above.M. complera could sprout new leaves in photosynthesis active radiation of 0.16–19.22 μmol·m?2·s?1 (8–961 lx), or 10 μmol·m?2·s?1 for above 6 h. Keywords Muehlewbeckia complera - Shade tolerance - Cultivation - Photosynthesis CLC number S602.1 Document code A Foundation item: This study was supported by the Research Foundation of Northeast Forestry University.Biography: YUE Hua (1962-), female, Associate professor in Northeast Forestry University, Harbin 150040, P. R. China.Responsible editor: Zhu Hong

Effects of Shading Treatments on Growth of Asimina triloba(L.) Dunal Seedlings

[Objective]The study was conducted to investigate the effects of shading treatments on growth of Asimina triloba （L） Dunal seedlings and provided the theoretical basis for seedling production. [Method]70 day-old A. triloba seedlings had similar stem diameter and plant height and good growth vigour were taken as tested materials in 2005. 4 light gradient treatments which were the natural light with 100% light intensity, one-layer, two-layer and three-layer black shading network with the light transmittance rate of 50%, 25% and 12.5% were set up to study the effects of different shading treatments on growth of A. triloba. [ Result] With the shading treatments of one-layer and two-layer net, the plants of A. triloba seedlings grew rapidly. As the intensity of illumination decreased, the cetents of chlorophyll a （ Chl. a）, chlorophyll b （ Chl. b） and total chlorophyll increased at first and then reduced. At the same time the chlorophyll a/b value became smaller. Under natural light, the plants tended to consume more water and the soil temperature at 15：00 p. m was higher. There was a smaller difference among various treatments. [ Conclusion]The suitable shading treatment to the growth of A. triloba seedlings was under the light transmittance rate of 50% and height and stem diameter of trees increased fast. Chlorophyll a （ Chl. a）, chlorophyll b （ Chl. b） content in leaves of A. triloba seedlings were highest comparing with those in other conditions.