色匹配函数通过构建地物反射光的光谱分布与颜色三刺激值的关系可将任意波段的信息映射到三原色基准值上,经过色彩空间的转换后重建多光谱遥感影像。针对大多数多光谱传感器在可见光内波段数量有限、波段通道较窄且波段间隔不均匀,直接...色匹配函数通过构建地物反射光的光谱分布与颜色三刺激值的关系可将任意波段的信息映射到三原色基准值上,经过色彩空间的转换后重建多光谱遥感影像。针对大多数多光谱传感器在可见光内波段数量有限、波段通道较窄且波段间隔不均匀,直接在相邻波段间插值会使色匹配积分过程出现较大误差的问题,结合遥感数据的模拟和反向传播(Back Propagation,BP)神经网络,以可见光范围内通道设置丰富的近岸高光谱水色成像仪(Hyperspectral Imager for the Coastal Ocean,HICO)经色匹配函数和色彩空间转换后得到的R、G、B三刺激值作为网络输出值,其波段重建后得到的目标传感器的模拟波段作为输入值,训练得到适用于Landsat-8 OLI、Terra MODIS、Himawari-8 AHI传感器的真彩色影像合成模型。计算均值、标准差、平均梯度和信息熵这4类客观评价参数,并结合对真彩色影像和直方图的主观分析,结果表明该方法能丰富和扩展有限的波段信息,提高影像的清晰度、色彩饱和度以及包含的信息量,校正了三波段合成影像存在的色偏,解决了在原始数据波段数受限的情况下通过简单插补波段带入色匹配函数进行积分计算产成误差的问题。展开更多
Juveniles of the shore crab Hemigrapsus oregonensis are highly variable in color, ranging from the typical yellowish- green of adults to pure white and myriad patterns of white mottling and other disruptive markings, ...Juveniles of the shore crab Hemigrapsus oregonensis are highly variable in color, ranging from the typical yellowish- green of adults to pure white and myriad patterns of white mottling and other disruptive markings, but large individuals with white coloration appear to be very rare. Using image analysis to quantify the relative ＂whiteness＂ of beaches, we sampled crabs from nine locations in Washington State that varied widely in their amount of shell fragments and other light-colored material. The total proportion of white individuals in the different locations was strongly correlated to the proportion of white material on the beaches, but there was a striking difference between sexes. Although white specimens of both sexes declined significantly at sizes above 10 mm carapace width, white females generally persisted throughout the entire female size range on lighter-colored beaches while white males larger than 10 mm were virtually absent from all of the sampled populations. Pure white males held on dark backgrounds in captivity remained white, as they lack the dark chromatophores in their hypoderrnis needed to change color; off-white males became darker and in some cases lightened up again when transferred back to a white background. Behavioral differences between the sexes may result in differential mortality of white individuals by visual predators [Current Zoology 61 （4） 729-738, 2015 ].展开更多
文摘色匹配函数通过构建地物反射光的光谱分布与颜色三刺激值的关系可将任意波段的信息映射到三原色基准值上,经过色彩空间的转换后重建多光谱遥感影像。针对大多数多光谱传感器在可见光内波段数量有限、波段通道较窄且波段间隔不均匀,直接在相邻波段间插值会使色匹配积分过程出现较大误差的问题,结合遥感数据的模拟和反向传播(Back Propagation,BP)神经网络,以可见光范围内通道设置丰富的近岸高光谱水色成像仪(Hyperspectral Imager for the Coastal Ocean,HICO)经色匹配函数和色彩空间转换后得到的R、G、B三刺激值作为网络输出值,其波段重建后得到的目标传感器的模拟波段作为输入值,训练得到适用于Landsat-8 OLI、Terra MODIS、Himawari-8 AHI传感器的真彩色影像合成模型。计算均值、标准差、平均梯度和信息熵这4类客观评价参数,并结合对真彩色影像和直方图的主观分析,结果表明该方法能丰富和扩展有限的波段信息,提高影像的清晰度、色彩饱和度以及包含的信息量,校正了三波段合成影像存在的色偏,解决了在原始数据波段数受限的情况下通过简单插补波段带入色匹配函数进行积分计算产成误差的问题。
基金We thank the staff of the Shannon Point Marine Center and the National Science Foundation Research Experiences for Undergraduates program. We are also grateful to Rachael Ream, Justin Ly, and Marc Baciagalupi for their help in the field, and for the very helpful comments from two anonymous referees.
文摘Juveniles of the shore crab Hemigrapsus oregonensis are highly variable in color, ranging from the typical yellowish- green of adults to pure white and myriad patterns of white mottling and other disruptive markings, but large individuals with white coloration appear to be very rare. Using image analysis to quantify the relative ＂whiteness＂ of beaches, we sampled crabs from nine locations in Washington State that varied widely in their amount of shell fragments and other light-colored material. The total proportion of white individuals in the different locations was strongly correlated to the proportion of white material on the beaches, but there was a striking difference between sexes. Although white specimens of both sexes declined significantly at sizes above 10 mm carapace width, white females generally persisted throughout the entire female size range on lighter-colored beaches while white males larger than 10 mm were virtually absent from all of the sampled populations. Pure white males held on dark backgrounds in captivity remained white, as they lack the dark chromatophores in their hypoderrnis needed to change color; off-white males became darker and in some cases lightened up again when transferred back to a white background. Behavioral differences between the sexes may result in differential mortality of white individuals by visual predators [Current Zoology 61 （4） 729-738, 2015 ].
