Appearance-space texture synthesis

Appearance-space texture synthesis
Sylvain Lefebvre, Hugues Hoppe.
ACM Trans. Graphics (SIGGRAPH), 25(3), 2006.
Improved synthesis quality and efficiency by pre-transforming the exemplar.
Abstract: The traditional approach in texture synthesis is to compare color neighborhoods with those of an exemplar. We show that quality is greatly improved if pointwise colors are replaced by appearance vectors that incorporate nonlocal information such as feature and radiance-transfer data. We perform dimensionality reduction on these vectors prior to synthesis, to create a new appearance-space exemplar. Unlike a texton space, our appearance space is low-dimensional and Euclidean. Synthesis in this information-rich space lets us reduce runtime neighborhood vectors from 5x5 grids to just 4 locations. Building on this unifying framework, we introduce novel techniques for coherent anisometric synthesis, surface texture synthesis directly in an ordinary atlas, and texture advection. Remarkably, we achieve all these functionalities in real-time, or 3 to 4 orders of magnitude faster than prior work.
Hindsights: The main contribution of this paper is sometimes misinterpreted: it is not the use of PCA projection to accelerate texture neighborhood comparisons (which is already done in [Hertzmann et al 2001; Liang et al 2001; Lefebvre and Hoppe 2005]); rather it is the transformation of the exemplar texture itself (into a new appearance space) to let each transformed pixel encode nonlocal information.

See Design of tangent vector fields for interactive painting of oriented texture over a surface.