VLFeat is an open and portable library of computer vision algorithms. It aims at facilitating fast prototyping and reproducible research for computer vision scientists and students. It includes rigorous implementations of common building blocks such as feature detectors, feature extractors, (hierarchical) k-means clustering, randomized kd-tree matching, and super-pixelization. The source code and interfaces are fully documented. The library integrates directly with Matlab, a popular language for computer vision research. Categories and Subject Descriptors D.0 [Software]: General; I.2.10 [Artificial Intelligence]: Vision and Scene Understanding General Terms Algorithm, design, experimentation Keywords Computer vision, object recognition, image classification, visual features