|We introduce the term BTF (bidirectional texture function) to represent the appearance of texture as a function of viewing and illumination direction. When a surface is macroscopically rough, appearance has a complex dependence on illumination and viewing direction. We measured the BTF of 61 real-world surfaces by recording images of each surface with 205 different combinations of viewing and illumination directions. A table is provided which gives the illumination and viewing directions associated with each of the 205 images. The images are stored as 24-bit BMP files, and can readily be radiometrically calibrated .
Any of the 205 images for each sample can be downloaded individually by clicking on the appropriate sample in the graphical sample-list or the text-only sample-list .
An illustration of 3D texture mapping using the images of the database is provided.