Development of a multispectral camera system

A highly accurate multispectral camera and the application software have been developed as a practical system to capture digital images of the artworks stored in galleries and museums. Instead of recording color data in the conventional three RGB primary colors, the newly developed camera and the software carry out a pixel-wise estimation of spectral reflectance, the color data specific to the object, to enable the practical multispectral imaging. In order to realize the accurate multispectral imaging, the dynamic range of the camera is set to 14 bits or over and the output bits to 14 bits so as to allow capturing even when the difference in light quantity between the each channel is large. Further, a small-size rotary color filter was simultaneously developed to keep the camera to a practical size. We have developed software capable of selecting the optimum combination of color filters available in the market. Using this software, n types of color filter can be selected from m types of color filter giving a minimum Euclidean distance or minimum color difference in CIELAB color space between actual and estimated spectral reflectance as to 147 types of oil paint samples.