fig5

Figure 5. Scratch texture generation. The dark orange areas are the scratch trajectory randomly drawn by the operators. Following the trajectory, the cross-section of the scratch is vertically distributed in the image. Therefore, they are projected as straight lines at each pixel of the trajectory, forming the light orange areas. The pixel values of these areas, which are the original surface normals, are replaced by the scratched surface normals. As the trajectory may randomly turn in different directions at different places, the projected cross-section areas may be overlapped as the pink areas or skip some pixels as the green areas. The pixel values are replaced by averaged normals or interpolated normals.