The Weizmann Institute of Science
Faculty of Mathematics and Computer Science
Computer Vision Lab

"Clustering by Composition":

Unsupervised Discovery of Image Categories

Alon Faktor, Michal Irani

This webpage presents the paper "Clustering by Composition" - Unsupervised Discovery of Image Categories (ECCV 2012).
Paper [PDF]
PAMI extended version [PDF]
Proofs & Additional material [PDF]


We define a "good image cluster" as one in which images can be easily composed (like a puzzle) using pieces from each other, while are difficult to compose from images outside the cluster. The larger and more statistically significant the pieces are, the stronger the affinity between the images. This gives rise to unsupervised discovery of very challenging image categories. We further show how multiple images can be composed from each other simultaneously and efficiently using a collaborative randomized search algorithm. This collaborative process exploits the "wisdom of crowds of images", to obtain a sparse yet meaningful set of image affinities, and in time which is almost linear in the size of the image collection. "Clustering-by-Composition" can be applied to very few images (where a 'cluster model' cannot be 'learned'), as well as on benchmark evaluation datasets, and yields state-of-the-art results.

Code can be downloaded here


Ballet-Yoga tiny dataset [ZIP]
Animals tiny dataset [ZIP]
PASCAL subset [ZIP]