Chiao C C, Osorio D, Vorobyev M, Cronin T W
Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore 21250, USA.
J Opt Soc Am A Opt Image Sci Vis. 2000 Oct;17(10):1713-21. doi: 10.1364/josaa.17.001713.
We describe illumination spectra in forests and show that they can be accurately recovered from recorded digital video images. Natural illuminant spectra of 238 samples measured in temperate forests were characterized by principal-component analysis. The spectra can be accurately approximated by the mean and the first two principal components. Compared with illumination under open skies, the loci of forest illuminants are displaced toward the green region in the chromaticity plots, and unlike open sky illumination they cannot be characterized by correlated color temperature. We show that it is possible to recover illuminant spectra accurately from digital video images by a linear least-squares-fit estimation technique. The use of digital video data in spectral analysis provides a promising new approach to the studies of the spatial and temporal variation of illumination in natural scenes and the understanding of color vision in natural environments.
我们描述了森林中的光照光谱,并表明可以从记录的数字视频图像中准确恢复这些光谱。通过主成分分析对在温带森林中测量的238个样本的自然光源光谱进行了表征。这些光谱可以通过均值和前两个主成分进行精确近似。与开阔天空下的光照相比,森林光源的色度图中的轨迹向绿色区域偏移,并且与开阔天空光照不同,它们不能用相关色温来表征。我们表明,通过线性最小二乘拟合估计技术可以从数字视频图像中准确恢复光源光谱。在光谱分析中使用数字视频数据为研究自然场景中光照的时空变化以及理解自然环境中的色觉提供了一种有前途的新方法。