Using digital cameras to investigate animal colouration: estimating sensor sensitivity functions
Using digital cameras to investigate animal colouration: estimating sensor sensitivity functions
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DOI：
10.1007/s00265-010-1097-7
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发表时间：
2011-04-01
影响因子：
2.3
通讯作者：
Pike, Thomas W.
中科院分区：
文献类型：
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作者：
Pike, Thomas W.
分光光度计可以对颜色进行客观测量，因此正在迅速成为动物着色研究中的关键设备；然而，它们也有一些重大的局限性。例如，它们只能记录点样本，难以重建地形信息，而且在测量过程中通常要求受试者没有生命。最近，人们开始探索使用数码相机来替代分光光度法。特别是，这使得整个场景可以被捕获并客观地转换到动物颜色空间，从而提供使用分光光度法无法获得的空间(和潜在的时间)数据；然而，相机和动物颜色空间之间的映射需要了解相机传感器的光谱灵敏度功能。这些信息很少获得，而且直接测量传感器灵敏度的费用可能高得令人望而却步，技术要求也很高，而且很耗时。因此，在工程和计算科学中已经开发了各种方法，允许仅使用关于相机对有限数量的已知表面反射率的色块的响应的容易收集的数据来估计传感器灵敏度函数。在这里，我描述一种这样的方法的实际应用，并演示它如何以足够高的精确度恢复传感器灵敏度(包括在紫外线中)，以根据动物光感受器的量子捕获重建整个图像，计算值与通过分光光度测量确定的值非常接近。我讨论了这种方法的潜力，以促进我们对动物着色的理解。
Spectrophotometers allow the objective measurement of colour and as a result are rapidly becoming a key piece of equipment in the study of animal colouration; however, they also have some major limitations. For example, they can only record point samples, making it difficult to reconstruct topographical information, and they generally require subjects to be inanimate during measurement. Recently, the use of digital cameras has been explored as an alternative to spectrophotometry. In particular, this allows whole scenes to be captured and objectively converted to animal colour space, providing spatial (and potentially temporal) data that would be unobtainable using spectrophotometry; however, mapping between camera and animal colour spaces requires knowledge of the spectral sensitivity functions of the camera's sensors. This information is rarely available, and making direct measures of sensor sensitivity can be prohibitively expensive, technically demanding and time-consuming. As a result, various methods have been developed in the engineering and computing sciences that allow sensor sensitivity functions to be estimated using only readily collected data on the camera's response to a limited number of colour patches of known surface reflectance. Here, I describe the practical application of one such method and demonstrate how it allows the recovery of sensor sensitivities (including in the ultraviolet) with a high enough degree of accuracy to reconstruct whole images in terms of the quantal catches of an animal's photoreceptors, with calculated values that closely match those determined from spectrophotometric measurements. I discuss the potential for this method to advance our understanding of animal colouration.