Application of hyperspectral camera and spectrocolorimeter for colorimetric measurements on polychrome surfaces in a controlled environment

The aim of this work is to compare the data obtained with two technologies, namely a hyperspectral camera and a spectrocolorimeter, to study the color and colorimetric parameters of polychrome surfaces. These measurements are generally carried out with dedicated instruments, such as colorimeters and spectrophotometers, which require contact with the surface and cover areas of the order of tens of mm2. These two characteristics, contact and a very small analysis area, can severely limit the study of polychrome surfaces, as the measured areas are not necessarily representative of the entire surface. Furthermore, it is not always possible to touch the analyzed objects. A possible alternative is the use of compact hyperspectral cameras, such as Specim IQ, for the in situ study of the spectral and colorimetric characteristics of these surfaces. To better address this research, still in the preliminary phase, a measurement set with lighting geometry fixed at 45° with respect to the image plane was defined in the laboratory to uniformly illuminate the investigated surface and avoid having components reflected specularly on the camera lens. With this fixed shot geometry, a series of Labsphere color standards (eight different color samples) will be analyzed using four different color backgrounds. In this way, it will be possible to define the optimal operating characteristics of the hyperspectral camera for laboratory measurements aimed at studying the color of polychrome surfaces.