Imperial College London


Faculty of EngineeringDepartment of Electrical and Electronic Engineering

Reader in Computer Vision



+44 (0)20 7594 6220k.mikolajczyk




Electrical EngineeringSouth Kensington Campus





Publication Type

69 results found

Snoek C, Sande K, Rooij O, Huurnink B, Gemert J, Uijlings J, He J, Li X, Everts I, Nedovic V, Liempt M, Balen R, Yan F, Tahir M, Mikolajczyk K, Kittler J, Rijke M, Geusebroek J, Gevers T, Worring M, Smeulders A, Koelma Det al., 2008, The MediaMill TRECVID 2008 Semantic Video Search Engine, TRECVID Workshop

In this paper we describe our TRECVID 2008 video retrieval experiments. The MediaMill team participated in three tasks: concept detection, automatic search, and interac- tive search. Rather than continuing to increase the number of concept detectors available for retrieval, our TRECVID 2008 experiments focus on increasing the robustness of a small set of detectors using a bag-of-words approach. To that end, our concept detection experiments emphasize in particular the role of visual sampling, the value of color in- variant features, the influence of codebook construction, and the effectiveness of kernel-based learning parameters. For retrieval, a robust but limited set of concept detectors ne- cessitates the need to rely on as many auxiliary information channels as possible. Therefore, our automatic search ex- periments focus on predicting which information channel to trust given a certain topic, leading to a novel framework for predictive video retrieval. To improve the video retrieval re- sults further, our interactive search experiments investigate the roles of visualizing preview results for a certain browse- dimension and active learning mechanisms that learn to solve complex search topics by analysis from user brows- ing behavior. The 2008 edition of the TRECVID bench- mark has been the most successful MediaMill participation to date, resulting in the top ranking for both concept de- tection and interactive search, and a runner-up ranking for automatic retrieval. Again a lot has been learned during this year’s TRECVID campaign; we highlight the most im- portant lessons at the end of this paper.

Conference paper

Tuytelaars T, Mikolajczyk K, 2008, Local invariant feature detectors: A survey, Foundations and Trends in Computer Graphics and Vision, Vol: 3, Pages: 177-280, ISSN: 1572-2759

Journal article

Cai H, Mikolajczyk K, Matas J, 2008, Learning linear discriminant projections for dimensionality reduction of image descriptors, Proceedings of the British Machine Vision Conference, Pages: 51.5-51.10

This paper proposes a general method for improving image descriptors using discriminant projections. Two methods based on Linear Discriminant Analysis have been recently introduced in [3, 11] to improve matching performance of local descriptors and to reduce their dimensionality. These methods require large training set with ground truth of accurate point-to-point correspondences which limits their applicability. We demonstrate the theoretical equivalence of these methods and provide a means to derive projection vectors on data without available ground truth. It makes it possible to apply this technique and improve performance of any combination of interest point detectors-descriptors. We conduct an extensive evaluation of the discriminative projection methods in various application scenarios. The results validate the proposed method in viewpoint invariant matching and category recognition.

Conference paper

Uemura H, Ishikawa S, Mikolajczyk K, 2008, Feature Tracking and Motion Compensation for Action Recognition., Publisher: British Machine Vision Association, Pages: 1-10

Conference paper

Mikolajczyk K, Matas J, 2007, Improving descriptors for fast tree matching by optimal linear projection, 11th IEEE International Conference on Computer Vision, Publisher: IEEE, Pages: 337-344, ISSN: 1550-5499

Conference paper

Leibe B, Mikolajczyk K, Schiele B, 2006, Segmentation Based Multi-Cue Integration for Object Detection., Publisher: British Machine Vision Association, Pages: 1169-1178

Conference paper

Leibe B, Mikolajczyk K, Schiele B, 2006, Efficient Clustering and Matching for Object Class Recognition., Publisher: British Machine Vision Association, Pages: 789-798

Conference paper

Mikolajczyk K, Leibe B, Schiele B, 2006, Multiple object class detection with a generative model, Proceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition, Vol: 1, Pages: 26-33, ISSN: 1063-6919

In this paper we propose an approach capable of simultaneous recognition and localization of multiple object classes using a generative model. A novel hierarchical representation allows to represent individual images as well as various objects classes in a single, scale and rotation invariant model. The recognition method is based on a codebook representation where appearance clusters built from edge based features are shared among several object classes. A probabilistic model allows for reliable detection of various objects in the same image. The approach is highly efficient due to fast clustering and matching methods capable of dealing with millions of high dimensional features. The system shows excellent performance on several object categories over a wide range of scales, in-plane rotations, background clutter, and partial occlusions. The performance of the proposed multi-object class detection approach is competitive to state of the art approaches dedicated to a single object class recognition problem. © 2006 IEEE.

Journal article

Mikolajczyk K, Tuytelaars T, Schmid C, Zisserman A, Matas J, Schaffalitzky F, Kadir T, van Gool Let al., 2005, A comparison of affine region detectors, INTERNATIONAL JOURNAL OF COMPUTER VISION, Vol: 65, Pages: 43-72, ISSN: 0920-5691

Journal article

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