Polarized light scanning for cultural heritage investigation

Numerous cultural heritage art works have shiny surfaces resulting form gold, silver, and other metallic pigments. In addition varnish overlayer on oil paintings makes it challenging to retrieve true color information. This is due to the great effect of lighting condition when images are acquired and viewed. The reflection of light from such surfaces is a combination of the surface's specular and diffused light reflections. In this paper, this specific problems encountered when digitizing cultural heritage were discussed. Experimental results using the images acquired with a high-resolution large flat bed scanner, together with a mathematical method for processing the captured images were presented and discussed in detail. Focus was given in separating the diffused and specular components of the reflected light for the purpose of analytical imaging. The mathematical algorithm developed in this study enables imaging of cultural heritage with shiny and glossy surfaces effectively and efficiently.