The availability of quantitative online benchmarks for
low-level vision tasks such as stereo and optical flow has led
to significant progress in the respective fields. This paper
introduces such a benchmark for image matting. There are
three key factors for a successful benchmarking system: (a)
a challenging, high-quality ground truth test set; (b) an online
evaluation repository that is dynamically updated with
new results; (c) perceptually motivated error functions. Our
new benchmark strives to meet all three criteria.
We evaluated several matting methods with our benchmark
and show that their performance varies depending
on the error function. Also, our challenging test set reveals
problems of existing algorithms, not reflected in previously
reported results. We hope that our effort will
lead to considerable progress in the field of image matting,
and welcome the reader to visit our benchmark at
www.alphamatting.com.