Texture synthesis

Texture synthesis

Paul Billault

IMPA, Rio de Janeiro, Brasil

Training period person in charge: Luiz Velho

01/04/2001-06/07/2001

Abstract

Texture is an important aspect of computer graphics, because it allows increasing the realism of images. The synthesis of textures is one of the better ways to create texture images of arbitrary size. However, it remains difficult to develop an algorithm that is both efficient and capable of generating high quality results. I studied two algorithms very similar that reach very good performances: one designed by Wei L.-Y. and Levoy M. and the other by Ashikhmin M. The algorithms require a texture sample as input and generate an image of the size chosen by the user, so they are very easy to use.

The Wei-Levoy algorithm uses the locality and stationarity properties of the textures to synthesize an image pixel by pixel searching the pixel in the input sample with the nearest neighborhood from the one of the current pixel. As it is quite computationally expensive, multi-resolution pyramids and quantization acceleration bring efficient solutions.

The Ashikhmin algorithm is inspired from the first one. But it adds the idea of coherence in the synthesis. That is, the current pixel receives the value of an input pixel elected among a list of pixels candidates chosen because they are near from the pixels which was used to assign the pixels near from the current pixel. This algorithm is extremely efficient and gives high quality results for the class of natural textures.

I implemented those methods in Java, as the interface, which permits to load, save, display images and changing the parameters of the synthesis. I implemented also interesting applications of user control, allowing the user to impose some rules to the synthesis.

Methods