Stefan Harmeling

Group Leader

Alumni

Empirical Inference

http://people.tuebingen.mpg.de/h...

Overview
Publications

A detailed overview of my research can be found on my homepage.

68 results (View BibTeX file of all listed publications)

2016

Learning to Deblur

Schuler, C. J., Hirsch, M., Harmeling, S., Schölkopf, B.

IEEE Transactions on Pattern Analysis and Machine Intelligence, 38(7):1439-1451, IEEE, 2016 (article)

DOI [BibTex]

2016

Schuler, C. J., Hirsch, M., Harmeling, S., Schölkopf, B. Learning to Deblur IEEE Transactions on Pattern Analysis and Machine Intelligence, 38(7):1439-1451, IEEE, 2016 (article)

DOI [BibTex]

2015

Method and device for recovering a digital image from a sequence of observed digital images

Harmeling, S., Hirsch, M., Sra, S., Schölkopf, B., Schuler, C.

European Patent, No. 11767924.1, November 2015 (patent)

[BibTex]

2015

Harmeling, S., Hirsch, M., Sra, S., Schölkopf, B., Schuler, C. Method and device for recovering a digital image from a sequence of observed digital images European Patent, No. 11767924.1, November 2015 (patent)

[BibTex]

Towards denoising XMCD movies of fast magnetization dynamics using extended Kalman filter

Kopp, M., Harmeling, S., Schütz, G., Schölkopf, B., Fähnle, M.

Ultramicroscopy, 148, pages: 115-122, 2015 (article)

Abstract

The Kalman filter is a well-established approach to get information on the time-dependent state of a system from noisy observations. It was developed in the context of the Apollo project to see the deviation of the true trajectory of a rocket from the desired trajectory. Afterwards it was applied to many different systems with small numbers of components of the respective state vector (typically about 10). In all cases the equation of motion for the state vector was known exactly. The fast dissipative magnetization dynamics is often investigated by x-ray magnetic circular dichroism movies (XMCD movies), which are often very noisy. In this situation the number of components of the state vector is extremely large (about 105), and the equation of motion for the dissipative magnetization dynamics (especially the values of the material parameters of this equation) is not well known. In the present paper it is shown by theoretical considerations that – nevertheless – there is no principle problem for the use of the Kalman filter to denoise XMCD movies of fast dissipative magnetization dynamics.

Web DOI [BibTex]

Kopp, M., Harmeling, S., Schütz, G., Schölkopf, B., Fähnle, M. Towards denoising XMCD movies of fast magnetization dynamics using extended Kalman filter Ultramicroscopy, 148, pages: 115-122, 2015 (article)

Web DOI [BibTex]

Computing Functions of Random Variables via Reproducing Kernel Hilbert Space Representations

Schölkopf, B., Muandet, K., Fukumizu, K., Harmeling, S., Peters, J.

Statistics and Computing , 25(4):755-766, 2015 (article)

DOI [BibTex]

Schölkopf, B., Muandet, K., Fukumizu, K., Harmeling, S., Peters, J. Computing Functions of Random Variables via Reproducing Kernel Hilbert Space Representations Statistics and Computing , 25(4):755-766, 2015 (article)

DOI [BibTex]

2014

Method and device for blind correction of optical aberrations in a digital image

Schuler, C., Hirsch, M., Harmeling, S., Schölkopf, B.

International Patent Application, No. PCT/EP2012/068868, April 2014 (patent)

[BibTex]

2014

Schuler, C., Hirsch, M., Harmeling, S., Schölkopf, B. Method and device for blind correction of optical aberrations in a digital image International Patent Application, No. PCT/EP2012/068868, April 2014 (patent)

[BibTex]

Mask-Specific Inpainting with Deep Neural Networks

Köhler, R., Schuler, C., Schölkopf, B., Harmeling, S.

In Pattern Recognition (GCPR 2014), pages: 523-534, (Editors: X Jiang, J Hornegger, and R Koch), Springer, 2014, Lecture Notes in Computer Science (inproceedings)

PDF DOI [BibTex]

Köhler, R., Schuler, C., Schölkopf, B., Harmeling, S. Mask-Specific Inpainting with Deep Neural Networks In Pattern Recognition (GCPR 2014), pages: 523-534, (Editors: X Jiang, J Hornegger, and R Koch), Springer, 2014, Lecture Notes in Computer Science (inproceedings)

PDF DOI [BibTex]

Extreme events in gross primary production: a characterization across continents

Zscheischler, J., Reichstein, M., Harmeling, S., Rammig, A., Tomelleri, E., Mahecha, M.

Biogeosciences, 11, pages: 2909-2924, 2014 (article)

PDF Web DOI [BibTex]

Zscheischler, J., Reichstein, M., Harmeling, S., Rammig, A., Tomelleri, E., Mahecha, M. Extreme events in gross primary production: a characterization across continents Biogeosciences, 11, pages: 2909-2924, 2014 (article)

PDF Web DOI [BibTex]

A few extreme events dominate global interannual variability in gross primary production

Zscheischler, J., Mahecha, M., v Buttlar, J., Harmeling, S., Jung, M., Rammig, A., Randerson, J., Schölkopf, B., Seneviratne, S., Tomelleri, E., Zaehle, S., Reichstein, M.

Environmental Research Letters, 9(3):035001, 2014 (article)

PDF Web DOI [BibTex]

Zscheischler, J., Mahecha, M., v Buttlar, J., Harmeling, S., Jung, M., Rammig, A., Randerson, J., Schölkopf, B., Seneviratne, S., Tomelleri, E., Zaehle, S., Reichstein, M. A few extreme events dominate global interannual variability in gross primary production Environmental Research Letters, 9(3):035001, 2014 (article)

PDF Web DOI [BibTex]

Learning to Deblur

Schuler, C. J., Hirsch, M., Harmeling, S., Schölkopf, B.

In NIPS 2014 Deep Learning and Representation Learning Workshop, 28th Annual Conference on Neural Information Processing Systems (NIPS), 2014 (inproceedings)

link (url) [BibTex]

Schuler, C. J., Hirsch, M., Harmeling, S., Schölkopf, B. Learning to Deblur In NIPS 2014 Deep Learning and Representation Learning Workshop, 28th Annual Conference on Neural Information Processing Systems (NIPS), 2014 (inproceedings)

link (url) [BibTex]

2013

On a link between kernel mean maps and Fraunhofer diffraction, with an application to super-resolution beyond the diffraction limit

Harmeling, S., Hirsch, M., Schölkopf, B.

In IEEE Conference on Computer Vision and Pattern Recognition, pages: 1083-1090, IEEE, CVPR, 2013 (inproceedings)

DOI [BibTex]

2013

Harmeling, S., Hirsch, M., Schölkopf, B. On a link between kernel mean maps and Fraunhofer diffraction, with an application to super-resolution beyond the diffraction limit In IEEE Conference on Computer Vision and Pattern Recognition, pages: 1083-1090, IEEE, CVPR, 2013 (inproceedings)

DOI [BibTex]

A machine learning approach for non-blind image deconvolution

Schuler, C., Burger, H., Harmeling, S., Schölkopf, B.

In IEEE Conference on Computer Vision and Pattern Recognition, pages: 1067-1074, IEEE, CVPR, 2013 (inproceedings)

Web Web DOI [BibTex]

Schuler, C., Burger, H., Harmeling, S., Schölkopf, B. A machine learning approach for non-blind image deconvolution In IEEE Conference on Computer Vision and Pattern Recognition, pages: 1067-1074, IEEE, CVPR, 2013 (inproceedings)

Web Web DOI [BibTex]

How to Test the Quality of Reconstructed Sources in Independent Component Analysis (ICA) of EEG/MEG Data

Grosse-Wentrup, M., Harmeling, S., Zander, T., Hill, J., Schölkopf, B.

In Proceedings of the 3rd International Workshop on Pattern Recognition in NeuroImaging (PRNI), pages: 102-105, IEEE Xplore Digital Library, PRNI, 2013 (inproceedings)

PDF DOI [BibTex]

Grosse-Wentrup, M., Harmeling, S., Zander, T., Hill, J., Schölkopf, B. How to Test the Quality of Reconstructed Sources in Independent Component Analysis (ICA) of EEG/MEG Data In Proceedings of the 3rd International Workshop on Pattern Recognition in NeuroImaging (PRNI), pages: 102-105, IEEE Xplore Digital Library, PRNI, 2013 (inproceedings)

PDF DOI [BibTex]

Improving alpha matting and motion blurred foreground estimation

Köhler, R., Hirsch, M., Schölkopf, B., Harmeling, S.

In IEEE Conference on Image Processing (ICIP), pages: 3446-3450, IEEE, ICIP, 2013 (inproceedings)

PDF DOI [BibTex]

Köhler, R., Hirsch, M., Schölkopf, B., Harmeling, S. Improving alpha matting and motion blurred foreground estimation In IEEE Conference on Image Processing (ICIP), pages: 3446-3450, IEEE, ICIP, 2013 (inproceedings)

PDF DOI [BibTex]

Detection and attribution of large spatiotemporal extreme events in Earth observation data

Zscheischler, J., Mahecha, M., Harmeling, S., Reichstein, M.

Ecological Informatics, 15, pages: 66-73, 2013 (article)

Abstract

Latest climate projections suggest that both frequency and intensity of climate extremes will be substantially modified over the course of the coming decades. As a consequence, we need to understand to what extent and via which pathways climate extremes affect the state and functionality of terrestrial ecosystems and the associated biogeochemical cycles on a global scale. So far the impacts of climate extremes on the terrestrial biosphere were mainly investigated on the basis of case studies, while global assessments are widely lacking. In order to facilitate global analysis of this kind, we present a methodological framework that firstly detects spatiotemporally contiguous extremes in Earth observations, and secondly infers the likely pathway of the preceding climate anomaly. The approach does not require long time series, is computationally fast, and easily applicable to a variety of data sets with different spatial and temporal resolutions. The key element of our analysis strategy is to directly search in the relevant observations for spatiotemporally connected components exceeding a certain percentile threshold. We also put an emphasis on characterization of extreme event distribution, and scrutinize the attribution issue. We exemplify the analysis strategy by exploring the fraction of absorbed photosynthetically active radiation (fAPAR) from 1982 to 2011. Our results suggest that the hot spots of extremes in fAPAR lie in Northeastern Brazil, Southeastern Australia, Kenya and Tanzania. Moreover, we demonstrate that the size distribution of extremes follow a distinct power law. The attribution framework reveals that extremes in fAPAR are primarily driven by phases of water scarcity.

Web DOI [BibTex]

Zscheischler, J., Mahecha, M., Harmeling, S., Reichstein, M. Detection and attribution of large spatiotemporal extreme events in Earth observation data Ecological Informatics, 15, pages: 66-73, 2013 (article)

Web DOI [BibTex]

Maximizing Kepler science return per telemetered pixel: Detailed models of the focal plane in the two-wheel era

Hogg, D. W., Angus, R., Barclay, T., Dawson, R., Fergus, R., Foreman-Mackey, D., Harmeling, S., Hirsch, M., Lang, D., Montet, B. T., Schiminovich, D., Schölkopf, B.

arXiv:1309.0653, 2013 (techreport)

link (url) [BibTex]

Hogg, D. W., Angus, R., Barclay, T., Dawson, R., Fergus, R., Foreman-Mackey, D., Harmeling, S., Hirsch, M., Lang, D., Montet, B. T., Schiminovich, D., Schölkopf, B. Maximizing Kepler science return per telemetered pixel: Detailed models of the focal plane in the two-wheel era arXiv:1309.0653, 2013 (techreport)

link (url) [BibTex]

Maximizing Kepler science return per telemetered pixel: Searching the habitable zones of the brightest stars

Montet, B. T., Angus, R., Barclay, T., Dawson, R., Fergus, R., Foreman-Mackey, D., Harmeling, S., Hirsch, M., Hogg, D. W., Lang, D., Schiminovich, D., Schölkopf, B.

arXiv:1309.0654, 2013 (techreport)

link (url) [BibTex]

Montet, B. T., Angus, R., Barclay, T., Dawson, R., Fergus, R., Foreman-Mackey, D., Harmeling, S., Hirsch, M., Hogg, D. W., Lang, D., Schiminovich, D., Schölkopf, B. Maximizing Kepler science return per telemetered pixel: Searching the habitable zones of the brightest stars arXiv:1309.0654, 2013 (techreport)

link (url) [BibTex]

2012

Image denoising: Can plain Neural Networks compete with BM3D?

Burger, H., Schuler, C., Harmeling, S.

In pages: 2392 - 2399, 25th IEEE Conference on Computer Vision and Pattern Recognition (CVPR), June 2012 (inproceedings)

Abstract

Image denoising can be described as the problem of mapping from a noisy image to a noise-free image. The best currently available denoising methods approximate this mapping with cleverly engineered algorithms. In this work we attempt to learn this mapping directly with a plain multi layer perceptron (MLP) applied to image patches. While this has been done before, we will show that by training on large image databases we are able to compete with the current state-of-the-art image denoising methods. Furthermore, our approach is easily adapted to less extensively studied types of noise (by merely exchanging the training data), for which we achieve excellent results as well.

PDF Web DOI [BibTex]

2012

Burger, H., Schuler, C., Harmeling, S. Image denoising: Can plain Neural Networks compete with BM3D? In pages: 2392 - 2399, 25th IEEE Conference on Computer Vision and Pattern Recognition (CVPR), June 2012 (inproceedings)

PDF Web DOI [BibTex]

Climate classifications: the value of unsupervised clustering

Zscheischler, J., Mahecha, M., Harmeling, S.

In Proceedings of the International Conference on Computational Science , 9, pages: 897-906, Procedia Computer Science, (Editors: H. Ali, Y. Shi, D. Khazanchi, M. Lees, G.D. van Albada, J. Dongarra, P.M.A. Sloot, J. Dongarra), Elsevier, Amsterdam, Netherlands, ICCS, June 2012 (inproceedings)

Abstract

Classifying the land surface according to dierent climate zones is often a prerequisite for global diagnostic or predictive modelling studies. Classical classifications such as the prominent K¨oppen–Geiger (KG) approach rely on heuristic decision rules. Although these heuristics may transport some process understanding, such a discretization may appear “arbitrary” from a data oriented perspective. In this contribution we compare the precision of a KG classification to an unsupervised classification (k-means clustering). Generally speaking, we revisit the problem of “climate classification” by investigating the inherent patterns in multiple data streams in a purely data driven way. One question is whether we can reproduce the KG boundaries by exploring dierent combinations of climate and remotely sensed vegetation variables. In this context we also investigate whether climate and vegetation variables build similar clusters. In terms of statistical performances, k-means clearly outperforms classical climate classifications. However, a subsequent stability analysis only reveals a meaningful number of clusters if both climate and vegetation data are considered in the analysis. This is a setback for the hope to explain vegetation by means of climate alone. Clearly, classification schemes like K¨oppen-Geiger will play an important role in the future. However, future developments in this area need to be assessed based on data driven approaches.

Web DOI [BibTex]

Zscheischler, J., Mahecha, M., Harmeling, S. Climate classifications: the value of unsupervised clustering In Proceedings of the International Conference on Computational Science , 9, pages: 897-906, Procedia Computer Science, (Editors: H. Ali, Y. Shi, D. Khazanchi, M. Lees, G.D. van Albada, J. Dongarra, P.M.A. Sloot, J. Dongarra), Elsevier, Amsterdam, Netherlands, ICCS, June 2012 (inproceedings)

Web DOI [BibTex]

Expectation-Maximization methods for solving (PO)MDPs and optimal control problems

Toussaint, M., Storkey, A., Harmeling, S.

In Inference and Learning in Dynamic Models, (Editors: Barber, D., Cemgil, A.T. and Chiappa, S.), Cambridge University Press, Cambridge, UK, January 2012 (inbook) In press

PDF [BibTex]

Toussaint, M., Storkey, A., Harmeling, S. Expectation-Maximization methods for solving (PO)MDPs and optimal control problems In Inference and Learning in Dynamic Models, (Editors: Barber, D., Cemgil, A.T. and Chiappa, S.), Cambridge University Press, Cambridge, UK, January 2012 (inbook) In press

PDF [BibTex]

Blind Correction of Optical Aberrations

Schuler, C., Hirsch, M., Harmeling, S., Schölkopf, B.

In Computer Vision - ECCV 2012, LNCS Vol. 7574, pages: 187-200, (Editors: A Fitzgibbon, S Lazebnik, P Perona, Y Sato, and C Schmid), Springer, Berlin, Germany, 12th IEEE European Conference on Computer Vision, ECCV, 2012 (inproceedings)

Abstract

Camera lenses are a critical component of optical imaging systems, and lens imperfections compromise image quality. While traditionally, sophisticated lens design and quality control aim at limiting optical aberrations, recent works [1,2,3] promote the correction of optical flaws by computational means. These approaches rely on elaborate measurement procedures to characterize an optical system, and perform image correction by non-blind deconvolution. In this paper, we present a method that utilizes physically plausible assumptions to estimate non-stationary lens aberrations blindly, and thus can correct images without knowledge of specifics of camera and lens. The blur estimation features a novel preconditioning step that enables fast deconvolution. We obtain results that are competitive with state-of-the-art non-blind approaches.

PDF Web DOI [BibTex]

Schuler, C., Hirsch, M., Harmeling, S., Schölkopf, B. Blind Correction of Optical Aberrations In Computer Vision - ECCV 2012, LNCS Vol. 7574, pages: 187-200, (Editors: A Fitzgibbon, S Lazebnik, P Perona, Y Sato, and C Schmid), Springer, Berlin, Germany, 12th IEEE European Conference on Computer Vision, ECCV, 2012 (inproceedings)

PDF Web DOI [BibTex]

Image denoising with multi-layer perceptrons, part 2: training trade-offs and analysis of their mechanisms

Burger, H., Schuler, C., Harmeling, S.

2012 (article) Submitted

Web [BibTex]

Burger, H., Schuler, C., Harmeling, S. Image denoising with multi-layer perceptrons, part 2: training trade-offs and analysis of their mechanisms 2012 (article) Submitted

Web [BibTex]

Recording and Playback of Camera Shake: Benchmarking Blind Deconvolution with a Real-World Database

Köhler, R., Hirsch, M., Mohler, B., Schölkopf, B., Harmeling, S.

In Computer Vision - ECCV 2012, LNCS Vol. 7578, pages: 27-40, (Editors: A. Fitzgibbon, S. Lazebnik, P. Perona, Y. Sato, and C. Schmid), Springer, Berlin, Germany, 12th European Conference on Computer Vision, ECCV , 2012 (inproceedings)

Abstract

Motion blur due to camera shake is one of the predominant sources of degradation in handheld photography. Single image blind deconvolution (BD) or motion deblurring aims at restoring a sharp latent image from the blurred recorded picture without knowing the camera motion that took place during the exposure. BD is a long-standing problem, but has attracted much attention recently, cumulating in several algorithms able to restore photos degraded by real camera motion in high quality. In this paper, we present a benchmark dataset for motion deblurring that allows quantitative performance evaluation and comparison of recent approaches featuring non-uniform blur models. To this end, we record and analyse real camera motion, which is played back on a robot platform such that we can record a sequence of sharp images sampling the six dimensional camera motion trajectory. The goal of deblurring is to recover one of these sharp images, and our dataset contains all information to assess how closely various algorithms approximate that goal. In a comprehensive comparison, we evaluate state-of-the-art single image BD algorithms incorporating uniform and non-uniform blur models.

PDF DOI [BibTex]

Köhler, R., Hirsch, M., Mohler, B., Schölkopf, B., Harmeling, S. Recording and Playback of Camera Shake: Benchmarking Blind Deconvolution with a Real-World Database In Computer Vision - ECCV 2012, LNCS Vol. 7578, pages: 27-40, (Editors: A. Fitzgibbon, S. Lazebnik, P. Perona, Y. Sato, and C. Schmid), Springer, Berlin, Germany, 12th European Conference on Computer Vision, ECCV , 2012 (inproceedings)

PDF DOI [BibTex]

Significant global reduction of carbon uptake by water-cycle driven extreme vegetation anomalies

Zscheischler, J., Mahecha, M., von Buttlar, J., Harmeling, S., Jung, M., Randerson, J., Reichstein, M.

Nature Geoscience, 2012 (article) In revision

[BibTex]

Zscheischler, J., Mahecha, M., von Buttlar, J., Harmeling, S., Jung, M., Randerson, J., Reichstein, M. Significant global reduction of carbon uptake by water-cycle driven extreme vegetation anomalies Nature Geoscience, 2012 (article) In revision

[BibTex]

Image denoising with multi-layer perceptrons, part 1: comparison with existing algorithms and with bounds

Burger, H., Schuler, C., Harmeling, S.

2012 (article) Submitted

Web [BibTex]

Burger, H., Schuler, C., Harmeling, S. Image denoising with multi-layer perceptrons, part 1: comparison with existing algorithms and with bounds 2012 (article) Submitted

Web [BibTex]

Image analysis for cosmology: results from the GREAT10 Galaxy Challenge

Kitching, T. D., Balan, S. T., Bridle, S., Cantale, N., Courbin, F., Eifler, T., Gentile, M., Gill, M. S. S., Harmeling, S., Heymans, C., others,

Monthly Notices of the Royal Astronomical Society, 423(4):3163-3208, Oxford University Press, 2012 (article)

DOI [BibTex]

Kitching, T. D., Balan, S. T., Bridle, S., Cantale, N., Courbin, F., Eifler, T., Gentile, M., Gill, M. S. S., Harmeling, S., Heymans, C., others, Image analysis for cosmology: results from the GREAT10 Galaxy Challenge Monthly Notices of the Royal Astronomical Society, 423(4):3163-3208, Oxford University Press, 2012 (article)

DOI [BibTex]

2011

Non-stationary correction of optical aberrations

Schuler, C., Hirsch, M., Harmeling, S., Schölkopf, B.

In pages: 659-666 , (Editors: DN Metaxas and L Quan and A Sanfeliu and LJ Van Gool), IEEE, Piscataway, NJ, USA, 13th IEEE International Conference on Computer Vision (ICCV), November 2011 (inproceedings)

Abstract

Taking a sharp photo at several megapixel resolution traditionally relies on high grade lenses. In this paper, we present an approach to alleviate image degradations caused by imperfect optics. We rely on a calibration step to encode the optical aberrations in a space-variant point spread function and obtain a corrected image by non-stationary deconvolution. By including the Bayer array in our image formation model, we can perform demosaicing as part of the deconvolution.

PDF Web DOI [BibTex]

2011

Schuler, C., Hirsch, M., Harmeling, S., Schölkopf, B. Non-stationary correction of optical aberrations In pages: 659-666 , (Editors: DN Metaxas and L Quan and A Sanfeliu and LJ Van Gool), IEEE, Piscataway, NJ, USA, 13th IEEE International Conference on Computer Vision (ICCV), November 2011 (inproceedings)

PDF Web DOI [BibTex]

Fast removal of non-uniform camera shake

Hirsch, M., Schuler, C., Harmeling, S., Schölkopf, B.

In pages: 463-470 , (Editors: DN Metaxas and L Quan and A Sanfeliu and LJ Van Gool), IEEE, Piscataway, NJ, USA, 13th IEEE International Conference on Computer Vision (ICCV), November 2011 (inproceedings)

Abstract

Camera shake leads to non-uniform image blurs. State-of-the-art methods for removing camera shake model the blur as a linear combination of homographically transformed versions of the true image. While this is conceptually interesting, the resulting algorithms are computationally demanding. In this paper we develop a forward model based on the efficient filter flow framework, incorporating the particularities of camera shake, and show how an efficient algorithm for blur removal can be obtained. Comprehensive comparisons on a number of real-world blurry images show that our approach is not only substantially faster, but it also leads to better deblurring results.

PDF Web DOI [BibTex]

Hirsch, M., Schuler, C., Harmeling, S., Schölkopf, B. Fast removal of non-uniform camera shake In pages: 463-470 , (Editors: DN Metaxas and L Quan and A Sanfeliu and LJ Van Gool), IEEE, Piscataway, NJ, USA, 13th IEEE International Conference on Computer Vision (ICCV), November 2011 (inproceedings)

PDF Web DOI [BibTex]

Improving Denoising Algorithms via a Multi-scale Meta-procedure

Burger, H., Harmeling, S.

In Pattern Recognition, pages: 206-215, (Editors: Mester, R. , M. Felsberg), Springer, Berlin, Germany, 33rd DAGM Symposium, September 2011 (inproceedings)

Abstract

Many state-of-the-art denoising algorithms focus on recovering high-frequency details in noisy images. However, images corrupted by large amounts of noise are also degraded in the lower frequencies. Thus properly handling all frequency bands allows us to better denoise in such regimes. To improve existing denoising algorithms we propose a meta-procedure that applies existing denoising algorithms across different scales and combines the resulting images into a single denoised image. With a comprehensive evaluation we show that the performance of many state-of-the-art denoising algorithms can be improved.

PDF DOI [BibTex]

Burger, H., Harmeling, S. Improving Denoising Algorithms via a Multi-scale Meta-procedure In Pattern Recognition, pages: 206-215, (Editors: Mester, R. , M. Felsberg), Springer, Berlin, Germany, 33rd DAGM Symposium, September 2011 (inproceedings)

PDF DOI [BibTex]

Automatic foreground-background refocusing

Loktyushin, A., Harmeling, S.

In pages: 3445-3448, (Editors: Macq, B. , P. Schelkens), IEEE, Piscataway, NJ, USA, 18th IEEE International Conference on Image Processing (ICIP), September 2011 (inproceedings)

Abstract

A challenging problem in image restoration is to recover an image with a blurry foreground. Such images can easily occur with modern cameras, when the auto-focus aims mistakenly at the background (which will appear sharp) instead of the foreground, where usually the object of interest is. In this paper we propose an automatic procedure that (i) estimates the amount of out-of-focus blur, (ii) segments the image into foreground and background incorporating clues from the blurriness, (iii) recovers the sharp foreground, and finally (iv) blurs the background to refocus the scene. On several real photographs with blurry foreground and sharp background, we demonstrate the effectiveness and limitations of our method.

Web DOI [BibTex]

Loktyushin, A., Harmeling, S. Automatic foreground-background refocusing In pages: 3445-3448, (Editors: Macq, B. , P. Schelkens), IEEE, Piscataway, NJ, USA, 18th IEEE International Conference on Image Processing (ICIP), September 2011 (inproceedings)

Web DOI [BibTex]

Gravitational Lensing Accuracy Testing 2010 (GREAT10) Challenge Handbook

Kitching, T., Amara, A., Gill, M., Harmeling, S., Heymans, C., Massey, R., Rowe, B., Schrabback, T., Voigt, L., Balan, S., Bernstein, G., Bethge, M., Bridle, S., Courbin, F., Gentile, M., Heavens, A., Hirsch, M., Hosseini, R., Kiessling, A., Kirk, D., Kuijken, K., Mandelbaum, R., Moghaddam, B., Nurbaeva, G., Paulin-Henriksson, S., Rassat, A., Rhodes, J., Schölkopf, B., Shawe-Taylor, J., Shmakova, M., Taylor, A., Velander, M., van Waerbeke, L., Witherick, D., Wittman, D.

Annals of Applied Statistics, 5(3):2231-2263, September 2011 (article)

Abstract

GRavitational lEnsing Accuracy Testing 2010 (GREAT10) is a public image analysis challenge aimed at the development of algorithms to analyze astronomical images. Specifically, the challenge is to measure varying image distortions in the presence of a variable convolution kernel, pixelization and noise. This is the second in a series of challenges set to the astronomy, computer science and statistics communities, providing a structured environment in which methods can be improved and tested in preparation for planned astronomical surveys. GREAT10 extends upon previous work by introducing variable fields into the challenge. The “Galaxy Challenge” involves the precise measurement of galaxy shape distortions, quantified locally by two parameters called shear, in the presence of a known convolution kernel. Crucially, the convolution kernel and the simulated gravitational lensing shape distortion both now vary as a function of position within the images, as is the case for real data. In addition, we introduce the “Star Challenge” that concerns the reconstruction of a variable convolution kernel, similar to that in a typical astronomical observation. This document details the GREAT10 Challenge for potential participants. Continually updated information is also available from www.greatchallenges.info.

PDF Web DOI [BibTex]

Online Multi-frame Blind Deconvolution with Super-resolution and Saturation Correction

Hirsch, M., Harmeling, S., Sra, S., Schölkopf, B.

Astronomy & Astrophysics, 531(A9):11, July 2011 (article)

Abstract

Astronomical images taken by ground-based telescopes suffer degradation due to atmospheric turbulence. This degradation can be tackled by costly hardware-based approaches such as adaptive optics, or by sophisticated software-based methods such as lucky imaging, speckle imaging, or multi-frame deconvolution. Software-based methods process a sequence of images to reconstruct a deblurred high-quality image. However, existing approaches are limited in one or several aspects: (i) they process all images in batch mode, which for thousands of images is prohibitive; (ii) they do not reconstruct a super-resolved image, even though an image sequence often contains enough information; (iii) they are unable to deal with saturated pixels; and (iv) they are usually non-blind, i.e., they assume the blur kernels to be known. In this paper we present a new method for multi-frame deconvolution called online blind deconvolution (OBD) that overcomes all these limitations simultaneously. Encouraging results on simulated and real astronomical images demonstrate that OBD yields deblurred images of comparable and often better quality than existing approaches.

PDF DOI [BibTex]

Hirsch, M., Harmeling, S., Sra, S., Schölkopf, B. Online Multi-frame Blind Deconvolution with Super-resolution and Saturation Correction Astronomy & Astrophysics, 531(A9):11, July 2011 (article)

PDF DOI [BibTex]

Greedy Learning of Binary Latent Trees

Harmeling, S., Williams, C.

IEEE Transactions on Pattern Analysis and Machine Intelligence, 33(6):1087-1097, June 2011 (article)

Abstract

Inferring latent structures from observations helps to model and possibly also understand underlying data generating processes. A rich class of latent structures are hierarchical latent class (HLC) models. Zhang (2004) proposed a search algorithm for learning such models that can find good solutions but is often computationally expensive. As an alternative we investigate two greedy procedures: the BIN-G algorithm determines both the structure of the tree and the cardinality of the latent variables in a bottom-up fashion. The BIN-A algorithm first determines the tree structure using agglomerative hierarchical clustering, and then determines the cardinality of the latent variables as for BIN-G. We show that even with restricting ourselves to binary trees we obtain HLC models of comparable quality to Zhang‘s solutions, while being faster to compute. This claim is validated by a comprehensive comparison on several datasets. Furthermore, we demonstrate that our methods are able to estimate int erpretable latent structures on real-world data with a large number of variables. By applying our method to a restricted version of the 20 newsgroups data these models turn out to be related to topic models, and on data from the PASCAL Visual Object Classes (VOC) 2007 challenge we show how such tree-structured models help us understand how objects co-occur in images.

PDF Web DOI [BibTex]

Harmeling, S., Williams, C. Greedy Learning of Binary Latent Trees IEEE Transactions on Pattern Analysis and Machine Intelligence, 33(6):1087-1097, June 2011 (article)

PDF Web DOI [BibTex]

Non-stationary Correction of Optical Aberrations

Schuler, C., Hirsch, M., Harmeling, S., Schölkopf, B.

(1), Max Planck Institute for Intelligent Systems, Tübingen, Germany, May 2011 (techreport)

Abstract

PDF [BibTex]

Schuler, C., Hirsch, M., Harmeling, S., Schölkopf, B. Non-stationary Correction of Optical Aberrations (1), Max Planck Institute for Intelligent Systems, Tübingen, Germany, May 2011 (techreport)

PDF [BibTex]

Removing noise from astronomical images using a pixel-specific noise model

Burger, H., Schölkopf, B., Harmeling, S.

In pages: 8, (Editors: H Lensch and SL Narasimhan and ME Testorf), IEEE, Piscataway, NJ, USA, IEEE International Conference on Computational Photography (ICCP), April 2011 (inproceedings)

Abstract

For digital photographs of astronomical objects, where exposure times are usually long and ISO settings high, the so-called dark-current is a significant source of noise. Dark-current refers to thermally generated electrons and is therefore present even in the absence of light. This paper presents a novel approach for denoising astronomical images that have been corrupted by dark-current noise. Our method relies on a probabilistic description of the dark-current of each pixel of a given camera. The noise model is then combined with an image prior which is adapted to astronomical images. In a laboratory environment, we use a black and white CCD camera containing a cooling unit and show that our method is superior to existing methods in terms of root mean squared error. Furthermore, we show that our method is practically relevant by providing visually more appealing results on astronomical photographs taken with a single lens reflex CMOS camera.

Web DOI [BibTex]

Burger, H., Schölkopf, B., Harmeling, S. Removing noise from astronomical images using a pixel-specific noise model In pages: 8, (Editors: H Lensch and SL Narasimhan and ME Testorf), IEEE, Piscataway, NJ, USA, IEEE International Conference on Computational Photography (ICCP), April 2011 (inproceedings)

Web DOI [BibTex]

2010

Multiframe Blind Deconvolution, Super-Resolution, and Saturation Correction via Incremental EM

Harmeling, S., Sra, S., Hirsch, M., Schölkopf, B.

In Proceedings of the 17th International Conference on Image Processing (ICIP 2010), pages: 3313-3316, IEEE, Piscataway, NJ, USA, 17th International Conference on Image Processing (ICIP), September 2010 (inproceedings)

Abstract

We formulate the multiframe blind deconvolution problem in an incremental expectation maximization (EM) framework. Beyond deconvolution, we show how to use the same framework to address: (i) super-resolution despite noise and unknown blurring; (ii) saturationcorrection of overexposed pixels that confound image restoration. The abundance of data allows us to address both of these without using explicit image or blur priors. The end result is a simple but effective algorithm with no hyperparameters. We apply this algorithm to real-world images from astronomy and to super resolution tasks: for both, our algorithm yields increased resolution and deconvolved images simultaneously.

PDF Web DOI [BibTex]

2010

Harmeling, S., Sra, S., Hirsch, M., Schölkopf, B. Multiframe Blind Deconvolution, Super-Resolution, and Saturation Correction via Incremental EM In Proceedings of the 17th International Conference on Image Processing (ICIP 2010), pages: 3313-3316, IEEE, Piscataway, NJ, USA, 17th International Conference on Image Processing (ICIP), September 2010 (inproceedings)

PDF Web DOI [BibTex]

Method and device for recovering a digital image from a sequence of observed digital images

Harmeling, S., Hirsch, M., Sra, S., Schölkopf, B.

United States Provisional Patent Application, No 61387025, September 2010 (patent)

[BibTex]

Harmeling, S., Hirsch, M., Sra, S., Schölkopf, B. Method and device for recovering a digital image from a sequence of observed digital images United States Provisional Patent Application, No 61387025, September 2010 (patent)

[BibTex]

Results of the GREAT08 Challenge: An image analysis competition for cosmological lensing

Bridle, S., Balan, S., Bethge, M., Gentile, M., Harmeling, S., Heymans, C., Hirsch, M., Hosseini, R., Jarvis, M., Kirk, D., Kitching, T., Kuijken, K., Lewis, A., Paulin-Henriksson, S., Schölkopf, B., Velander, M., Voigt, L., Witherick, D., Amara, A., Bernstein, G., Courbin, F., Gill, M., Heavens, A., Mandelbaum, R., Massey, R., Moghaddam, B., Rassat, A., Refregier, A., Rhodes, J., Schrabback, T., Shawe-Taylor, J., Shmakova, M., van Waerbeke, L., Wittman, D.

Monthly Notices of the Royal Astronomical Society, 405(3):2044-2061, July 2010 (article)

Abstract

We present the results of the GREAT08 Challenge, a blind analysis challenge to infer weak gravitational lensing shear distortions from images. The primary goal was to stimulate new ideas by presenting the problem to researchers outside the shear measurement community. Six GREAT08 Team methods were presented at the launch of the Challenge and five additional groups submitted results during the 6 month competition. Participants analyzed 30 million simulated galaxies with a range in signal to noise ratio, point-spread function ellipticity, galaxy size, and galaxy type. The large quantity of simulations allowed shear measurement methods to be assessed at a level of accuracy suitable for currently planned future cosmic shear observations for the first time. Different methods perform well in different parts of simulation parameter space and come close to the target level of accuracy in several of these. A number of fresh ideas have emerged as a result of the Challenge including a re-examination of the process of combining information from different galaxies, which reduces the dependence on realistic galaxy modelling. The image simulations will become increasingly sophis- ticated in future GREAT challenges, meanwhile the GREAT08 simulations remain as a benchmark for additional developments in shear measurement algorithms.

Web DOI [BibTex]

Efficient Filter Flow for Space-Variant Multiframe Blind Deconvolution

Hirsch, M., Sra, S., Schölkopf, B., Harmeling, S.

In Proceedings of the 23rd IEEE Conference on Computer Vision and Pattern Recognition, pages: 607-614, IEEE, Piscataway, NJ, USA, CVPR, June 2010 (inproceedings)

Abstract

Ultimately being motivated by facilitating space-variant blind deconvolution, we present a class of linear transformations, that are expressive enough for space-variant filters, but at the same time especially designed for efficient matrix-vector-multiplications. Successful results on astronomical imaging through atmospheric turbulences and on noisy magnetic resonance images of constantly moving objects demonstrate the practical significance of our approach.

PDF Web DOI [BibTex]

Hirsch, M., Sra, S., Schölkopf, B., Harmeling, S. Efficient Filter Flow for Space-Variant Multiframe Blind Deconvolution In Proceedings of the 23rd IEEE Conference on Computer Vision and Pattern Recognition, pages: 607-614, IEEE, Piscataway, NJ, USA, CVPR, June 2010 (inproceedings)

PDF Web DOI [BibTex]

How to Explain Individual Classification Decisions

Baehrens, D., Schroeter, T., Harmeling, S., Kawanabe, M., Hansen, K., Müller, K.

Journal of Machine Learning Research, 11, pages: 1803-1831, June 2010 (article)

Abstract

After building a classifier with modern tools of machine learning we typically have a black box at hand that is able to predict well for unseen data. Thus, we get an answer to the question what is the most likely label of a given unseen data point. However, most methods will provide no answer why the model predicted a particular label for a single instance and what features were most influential for that particular instance. The only method that is currently able to provide such explanations are decision trees. This paper proposes a procedure which (based on a set of assumptions) allows to explain the decisions of any classification method.

PDF PDF [BibTex]

Baehrens, D., Schroeter, T., Harmeling, S., Kawanabe, M., Hansen, K., Müller, K. How to Explain Individual Classification Decisions Journal of Machine Learning Research, 11, pages: 1803-1831, June 2010 (article)

PDF PDF [BibTex]

Space-Variant Single-Image Blind Deconvolution for Removing Camera Shake

Harmeling, S., Hirsch, M., Schölkopf, B.

In Advances in Neural Information Processing Systems 23, pages: 829-837, (Editors: J Lafferty and CKI Williams and J Shawe-Taylor and RS Zemel and A Culotta), Curran, Red Hook, NY, USA, 24th Annual Conference on Neural Information Processing Systems (NIPS), 2010 (inproceedings)

Abstract

Modelling camera shake as a space-invariant convolution simplifies the problem of removing camera shake, but often insufficiently models actual motion blur such as those due to camera rotation and movements outside the sensor plane or when objects in the scene have different distances to the camera. In an effort to address these limitations, (i) we introduce a taxonomy of camera shakes, (ii) we build on a recently introduced framework for space-variant filtering by Hirsch et al. and a fast algorithm for single image blind deconvolution for space-invariant filters by Cho and Lee to construct a method for blind deconvolution in the case of space-variant blur, and (iii), we present an experimental setup for evaluation that allows us to take images with real camera shake while at the same time recording the spacevariant point spread function corresponding to that blur. Finally, we demonstrate that our method is able to deblur images degraded by spatially-varying blur originating from real camera shake, even without using additionally motion sensor information.

PDF Web [BibTex]

Harmeling, S., Hirsch, M., Schölkopf, B. Space-Variant Single-Image Blind Deconvolution for Removing Camera Shake In Advances in Neural Information Processing Systems 23, pages: 829-837, (Editors: J Lafferty and CKI Williams and J Shawe-Taylor and RS Zemel and A Culotta), Curran, Red Hook, NY, USA, 24th Annual Conference on Neural Information Processing Systems (NIPS), 2010 (inproceedings)

PDF Web [BibTex]

2009

An Incremental GEM Framework for Multiframe Blind Deconvolution, Super-Resolution, and Saturation Correction

Harmeling, S., Sra, S., Hirsch, M., Schölkopf, B.

(187), Max Planck Institute for Biological Cybernetics, Tübingen, Germany, November 2009 (techreport)

Abstract

We develop an incremental generalized expectation maximization (GEM) framework to model the multiframe blind deconvolution problem. A simplistic version of this problem was recently studied by Harmeling etal~cite{harmeling09}. We solve a more realistic version of this problem which includes the following major features: (i) super-resolution ability emph{despite} noise and unknown blurring; (ii) saturation-correction, i.e., handling of overexposed pixels that can otherwise confound the image processing; and (iii) simultaneous handling of color channels. These features are seamlessly integrated into our incremental GEM framework to yield simple but efficient multiframe blind deconvolution algorithms. We present technical details concerning critical steps of our algorithms, especially to highlight how all operations can be written using matrix-vector multiplications. We apply our algorithm to real-world images from astronomy and super resolution tasks. Our experimental results show that our methods yield improve d resolution and deconvolution at the same time.

PDF [BibTex]

2009

Harmeling, S., Sra, S., Hirsch, M., Schölkopf, B. An Incremental GEM Framework for Multiframe Blind Deconvolution, Super-Resolution, and Saturation Correction (187), Max Planck Institute for Biological Cybernetics, Tübingen, Germany, November 2009 (techreport)

PDF [BibTex]

Efficient Filter Flow for Space-Variant Multiframe Blind Deconvolution

Hirsch, M., Sra, S., Schölkopf, B., Harmeling, S.

(188), Max Planck Institute for Biological Cybernetics, Tübingen, Germany, November 2009 (techreport)

Abstract

PDF [BibTex]

Hirsch, M., Sra, S., Schölkopf, B., Harmeling, S. Efficient Filter Flow for Space-Variant Multiframe Blind Deconvolution (188), Max Planck Institute for Biological Cybernetics, Tübingen, Germany, November 2009 (techreport)

PDF [BibTex]

Inferring textual entailment with a probabilistically sound calculus

Harmeling, S.

Natural Language Engineering, 15(4):459-477, October 2009 (article)

Abstract

We introduce a system for textual entailment that is based on a probabilistic model of entailment. The model is defined using a calculus of transformations on dependency trees, which is characterized by the fact that derivations in that calculus preserve the truth only with a certain probability. The calculus is successfully evaluated on the datasets of the PASCAL Challenge on Recognizing Textual Entailment.

PDF Web DOI [BibTex]

Harmeling, S. Inferring textual entailment with a probabilistically sound calculus Natural Language Engineering, 15(4):459-477, October 2009 (article)

PDF Web DOI [BibTex]

Learning To Detect Unseen Object Classes by Between-Class Attribute Transfer

Lampert, C., Nickisch, H., Harmeling, S.

In CVPR 2009, pages: 951-958, IEEE Service Center, Piscataway, NJ, USA, IEEE Computer Society Conference on Computer Vision and Pattern Recognition, June 2009 (inproceedings)

Abstract

We study the problem of object classification when training and test classes are disjoint, i.e. no training examples of the target classes are available. This setup has hardly been studied in computer vision research, but it is the rule rather than the exception, because the world contains tens of thousands of different object classes and for only a very few of them image, collections have been formed and annotated with suitable class labels. In this paper, we tackle the problem by introducing attribute-based classification. It performs object detection based on a human-specified high-level description of the target objects instead of training images. The description consists of arbitrary semantic attributes, like shape, color or even geographic information. Because such properties transcend the specific learning task at hand, they can be pre-learned, e.g. from image datasets unrelated to the current task. Afterwards, new classes can be detected based on their attribute representation, without the need for a new training phase. In order to evaluate our method and to facilitate research in this area, we have assembled a new large-scale dataset, ldquoAnimals with Attributesrdquo, of over 30,000 animal images that match the 50 classes in Osherson's classic table of how strongly humans associate 85 semantic attributes with animal classes. Our experiments show that by using an attribute layer it is indeed possible to build a learning object detection system that does not require any training images of the target classes.

PDF Web DOI [BibTex]

Lampert, C., Nickisch, H., Harmeling, S. Learning To Detect Unseen Object Classes by Between-Class Attribute Transfer In CVPR 2009, pages: 951-958, IEEE Service Center, Piscataway, NJ, USA, IEEE Computer Society Conference on Computer Vision and Pattern Recognition, June 2009 (inproceedings)

PDF Web DOI [BibTex]

Online blind deconvolution for astronomical imaging

Harmeling, S., Hirsch, M., Sra, S., Schölkopf, B.

In Proceedings of the First IEEE International Conference Computational Photography (ICCP 2009), pages: 1-7, IEEE, Piscataway, NJ, USA, First IEEE International Conference on Computational Photography (ICCP), April 2009 (inproceedings)

Abstract

Atmospheric turbulences blur astronomical images taken by earth-based telescopes. Taking many short-time exposures in such a situation provides noisy images of the same object, where each noisy image has a different blur. Commonly astronomers apply a technique called “Lucky Imaging” that selects a few of the recorded frames that fulfill certain criteria, such as reaching a certain peak intensity (“Strehl ratio”). The selected frames are then averaged to obtain a better image. In this paper we introduce and analyze a new method that exploits all the frames and generates an improved image in an online fashion. Our initial experiments with controlled artificial data and real-world astronomical datasets yields promising results.

PDF Web DOI [BibTex]

Harmeling, S., Hirsch, M., Sra, S., Schölkopf, B. Online blind deconvolution for astronomical imaging In Proceedings of the First IEEE International Conference Computational Photography (ICCP 2009), pages: 1-7, IEEE, Piscataway, NJ, USA, First IEEE International Conference on Computational Photography (ICCP), April 2009 (inproceedings)

PDF Web DOI [BibTex]

2007

Bayesian Estimators for Robins-Ritovs Problem

Harmeling, S., Toussaint, M.

(EDI-INF-RR-1189), School of Informatics, University of Edinburgh, October 2007 (techreport)

Abstract

Bayesian or likelihood-based approaches to data analysis became very popular in the ﬁeld of Machine Learning. However, there exist theoretical results which question the general applicability of such approaches; among those a result by Robins and Ritov which introduce a speciﬁc example for which they prove that a likelihood-based estimator will fail (i.e. it does for certain cases not converge to a true parameter estimate, even given inﬁnite data). In this paper we consider various approaches to formulate likelihood-based estimators in this example, basically by considering various extensions of the presumed generative model of the data. We can derive estimators which are very similar to the classical Horvitz-Thompson and which also account for a priori knowledge of an observation probability function.

PDF [BibTex]

2007

Harmeling, S., Toussaint, M. Bayesian Estimators for Robins-Ritovs Problem (EDI-INF-RR-1189), School of Informatics, University of Edinburgh, October 2007 (techreport)

PDF [BibTex]

An Extensible Probabilistic Transformation-based Approach to the Third Recognizing Textual Entailment Challenge

Harmeling, S.

In TextEntail 2007, pages: 137-142, ACL-PASCAL Workshop on Textual Entailment and Paraphrasing, June 2007 (inproceedings)

Abstract

We introduce a system for textual entailment that is based on a probabilistic model of entailment. The model is defined using some calculus of transformations on dependency trees, which is characterized by the fact that derivations in that calculus preserve the truth only with a certain probability. We also describe a possible set of transformations (and with it implicitly a calculus) that was successfully applied to the RTE3 challenge data. However, our system can be improved in many ways and we see it as the starting point for a promising new approach to textual entailment.

Web [BibTex]

Harmeling, S. An Extensible Probabilistic Transformation-based Approach to the Third Recognizing Textual Entailment Challenge In TextEntail 2007, pages: 137-142, ACL-PASCAL Workshop on Textual Entailment and Paraphrasing, June 2007 (inproceedings)

Web [BibTex]

Exploring model selection techniques for nonlinear dimensionality reduction

Harmeling, S.

(EDI-INF-RR-0960), School of Informatics, University of Edinburgh, March 2007 (techreport)

Abstract

Nonlinear dimensionality reduction (NLDR) methods have become useful tools for practitioners who are faced with the analysis of high-dimensional data. Of course, not all NLDR methods are equally applicable to a particular dataset at hand. Thus it would be useful to come up with model selection criteria that help to choose among diﬀerent NLDR algorithms. This paper explores various approaches to this problem and evaluates them on controlled data sets. Comprehensive experiments will show that model selection scores based on stability are not useful, while scores based on Gaussian processes are helpful for the NLDR problem.

PDF Web [BibTex]

Harmeling, S. Exploring model selection techniques for nonlinear dimensionality reduction (EDI-INF-RR-0960), School of Informatics, University of Edinburgh, March 2007 (techreport)

PDF Web [BibTex]

2006

Probabilistic inference for solving (PO)MDPs

Toussaint, M., Harmeling, S., Storkey, A.

(934), School of Informatics, University of Edinburgh, December 2006 (techreport)

PDF [BibTex]

2006

Toussaint, M., Harmeling, S., Storkey, A. Probabilistic inference for solving (PO)MDPs (934), School of Informatics, University of Edinburgh, December 2006 (techreport)

PDF [BibTex]

From outliers to prototypes: Ordering data

Harmeling, S., Dornhege, G., Tax, D., Meinecke, F., Müller, K.

Neurocomputing, 69(13-15):1608-1618, August 2006 (article)

Abstract

We propose simple and fast methods based on nearest neighbors that order objects from high-dimensional data sets from typical points to untypical points. On the one hand, we show that these easy-to-compute orderings allow us to detect outliers (i.e. very untypical points) with a performance comparable to or better than other often much more sophisticated methods. On the other hand, we show how to use these orderings to detect prototypes (very typical points) which facilitate exploratory data analysis algorithms such as noisy nonlinear dimensionality reduction and clustering. Comprehensive experiments demonstrate the validity of our approach.

PDF PDF DOI [BibTex]

Harmeling, S., Dornhege, G., Tax, D., Meinecke, F., Müller, K. From outliers to prototypes: Ordering data Neurocomputing, 69(13-15):1608-1618, August 2006 (article)

PDF PDF DOI [BibTex]