Innovative approach to the digital documentation and rendering of the total appearance of fine drawings and its validation on Leonardo's Vitruvian Man

tThe paper presents a new technique for detecting and rendering the total appearance of a drawingwith the aim of digitally visualizing fine drawing collections with perceptive accuracy. A drawing’s totalappearance can be measured using equipment commonly found in a photographic studio. The systemconsists of four strobes and an RGB camera. The appearance is defined by its spatially varying spectralreflectance factor, surface macrostructure and surface microstructure. Using stereo-photometric princi-ples, images of each light source taken sequentially from 45◦by the normal and annularly at each 90◦angle (for four lights) were used to measure the surface normal and diffuse reflectance. An OpenGL viewerwas written to render images for specific geometries and for studio lighting. The pipeline from acquisitionto visualization was tested on the most famous drawing in existence, Leonardo da Vinci’s Vitruvian Man.