Spectral radiance measurements database
Our in situ spectral radiance data project was started in order to collect several thousand measurements of all different kinds of objects under various illuminations in consideration of typical scenes and objects that people capture.
The only commonly known source for some in-situ measured spectral radiances until now was ISO 17321-1. It describes the principle of how the color characterization of a digital camera works and provides spectral radiance for 14 common objects.
In many cases, the spectral radiation of objects is not only that of the reflected light. Some objects such as leaves have a transmissive part. In other instances, inter-reflections between the objects modify the spectral radiance in scenes. Therefore, some objects, such as the human skin, appear different in real life compared to the skin tones of a reflective color target.
One of the primary uses of the collected data is to create a scientific database for different studies related to natural objects. However, the main reason for accumulating the information is to provide training data for the color characterization of digital cameras in combination with their spectral sensitivities. Currently, a total number of approx. 2500 measurements are available. With the database, you can optimize your color correction matrix based on real-life data; this exceeds the potential of a ColorChecker by far.
What is the content?
The database divides into categories for thematic selection of objects, such as plants, human skin color, or illumination type. Each object contains the spectral reflection in the range from 380 to 780 nm in two variants: one includes the incident light, and on the other, this light is removed (white tile corrected).