Reconstructing knife/brush strokes on oil paintingsWritten by Paul Bourke
The following documents an exercise in creating high resolution 2.5D surfaces of knife and brush strokes from paintings, in this case a thick oil painting. The process is a standard photogrammetry one, except that the camera is moved across soomed into a small portion of the image in order to acquire the desired resolution. In this case the camera is pointing straight down (axis tangential to the painting surface) and moved in 4cm steps in both directions The result/aim is that any point on the surface is present in at least 6 photographs.
The painting is shown below, this is actually the 2.5D surface model viewed in a 3D package with the 16K high texture applied.
The side view in MetaShape Pro showing the camera positions (blue squares) is shown below.
The view without the texture map and employing shading to illuminate the surface texture is given below. For this painting the maximum height of the oil paint above the surface is almost 1cm.
And a zoom in on a portion of the above.
The following images are from a virtual camera close to the surface with the texture map applied.