The universal anti-fake grain mark includes carrier with visible color or monochromic pattern and adhered medium with enquired number and other information.
Iconographic changes:3 cases showed light patchy shadows along the streak line distribution;1 case showed patchy shadows confluent into a big patchy shadow.
Texture unit and texture spectrum can get the difference of the microtexture and the macrotexture of this two regions effectively so as to detect the target.
Note that in the image above, the dark outline and true CrossHatch shading have been omitted to clearly illustrate the Perspective Camera projection of the grid texture onto the surface.