Image Quilting and Apples

Image Quilting and Apples

By Zach BroderickA presentation of the paper “Image Quilting

for Texture Synthesis and Transfer” by Alexei A. Efros and William T. Freeman

Texture Synthesis

(Images taken from paper)

Sample of Texture

Infinitely Large Output

Output texture is:• Same resolution

• Non-repeating

• Seamless

• Must be perceived as “same”

Previous Methods• Tiling (bad seams, repetitive)• Stochastic (doesn’t work for structured)• Pixel-based (SLOW, poor for structured)• Random Patches/Blending (poor seams)

Image Quilting• Copy patches (like the random patch method) based on

neighborhood (like pixel method)• Faster (predetermined pixels/less search space), maintains

structure of regular textures• Seams smoothed with graph cut through least error path

(Image from Wikipedia)

Image Quilting

(Diagram from paper)

An In-Depth Look at the Image Quilting Algorithm: Overview

• Copy tiles from the source image to the destination image in a left to right, top to bottom fashion, with an overlap of about 1/6 the tile size on the top and left regions.

• In selecting each of these tiles, search the source image space S for the tile with the least mean squared error in the overlap region (the first tile can be selected at random).

• When copying each tile, calculate the minimum error path cut in each of the overlap regions, and only copy the portion of the tile within the cut.

Error Calculation

Path Cut

Path Cut Cont’d…

Texture Transfer• Algorithm can be generalized to provide texture transfer

capabilities (image from paper)

Problems• Repetition often occurs (see raspberries)• Occasional glaring seams (mutant tomatoes)

Demonstration

Questions?