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Image Processing Image Processing • • Class 1 Introduction Image Processing • 1 • – Oral or written exam (depends on the number of participants) after the lecturing period – Regular attendance in the tutorials required to qualify for the exam • These slides will be made available at http://www.inf.tu-dresden.de/content/institutes/ki/is/bv_ws0708.de.html • They are password protected. Access via… © 2007 Thomas Brox Image Processing Grading policy Tutorials start next week Prerequisites – Undergraduate mathematics – Some programming experience in C/C++ (for the programming assignments) Organizational issues • What type of lecture? – 2 hours classroom lecture, 2 hours tutorials – Tutorial consisting of mostly programming assignments and some theoretical assignments – Introductory course in the fields of image processing, computer vision, and pattern recognition – (Soft) requirement for starting a diploma thesis in this field Image Processing © 2007 Thomas Brox Organizational issues 2 Other courses This winter term: – Pattern Matching in Computer Vision (2+2, called Mustererkennung) • Next summer term (planned): – Computer Vision (2+2) – Image Segmentation (2+2) or Pattern Recognition and Machine Learning (2+2) – username: open – password: sesame © 2007 Thomas Brox 3 © 2007 Thomas Brox 4 Image Processing Image Processing What is an image? Where do images and image processing play a role? • Imaging (e.g. photography, ultrasound, x-ray, magnetic resonance) • Image enhancement (e.g. Adobe Photoshop) • Image and video compression • Computer graphics (model Æ image) • Computer vision (image Æ model) • Focus of this and the following courses: image enhancement and computer vision Author: Daniel Cremers • Digital image: regular grid • Continuous function of intensity values © 2007 Thomas Brox Image Processing 5 Image Processing Imaging – ultrasound, MRI Ultrasound image of a human embryo © 2007 Thomas Brox © 2007 Thomas Brox 6 Image enhancement - denoising Magnetic resonance image of a human head 7 © 2007 Thomas Brox 8 Image Processing Image Processing Image enhancement - deblurring Image compression - JPEG Welk et al. 2005: variational deblurring © 2007 Thomas Brox Image Processing 9 © 2007 Thomas Brox Image Processing Computer graphics – water simulation 10 Computer vision – 3D reconstruction Kolev et al. 2007: multiview reconstruction Guendelman et al. 2005: Simulating the flow of water with level sets © 2007 Thomas Brox 11 © 2007 Thomas Brox 12 Image Processing Image Processing Computer vision - segmentation Computer vision – human tracking Brox et al. 2007: 3D human pose tracking Wedel et al. 2007: obstacle detection and segmentation © 2007 Thomas Brox Image Processing 13 © 2007 Thomas Brox Image Processing Computer vision – human tracking 14 Difference between image processing and computer vision • Usually, the term “image processing” is used for the general subject of processing images with a computer • Computer vision signifies the specific task to make the computer interpret the content of images • This is a difficult and so far unsolved task • Computer vision has similar motivations as artificial intelligence and cognitive neuroscience Brox et al. 2007: 3D human pose tracking © 2007 Thomas Brox 15 © 2007 Thomas Brox 16 Image Processing Image Processing Why is computer vision difficult? • Vision is a natural and easy task for humans (and many animals) • This is not for free: ~50% of the primate’s cortex deals with the processing of visual information (Felleman-van Essen 1991) • Making a computer see like humans see means to solve a large part of the AI problem (this cannot be easy) • What do you see in this image? • Images are only a structured grid of numbers What’s that? Author: Daniel Cremers • A lot of high level knowledge and content information necessary © 2007 Thomas Brox Image Processing 17 • This is how the computer sees Einstein • Demonstrates what our brain achieves at the unconscious level © 2007 Thomas Brox Image Processing Importance of the spatial arrangement • • Image content is defined by the spatial arrangement of intensities • It is not sufficient to treat images as vectors and to analyze these vectors Zebra image © 2007 Thomas Brox Importance of image processing and computer vision Computer vision is a very young research field – Main computer vision conference (ICCV) founded in 1987 – Main computer vision journal (IJCV) founded in 1988 Same image with a different row length • Nonetheless, it belongs already to the most influential subfields of computer science; tendency: growing rapidly • By 2006, the International Journal of Computer Vision had the highest impact factor of all computer science journals: 6.085 • Impact factor in 2002: 2.03 • Computer vision applications not restricted by a small market but by the limited quality provided so far • 19 18 More research Æ more products © 2007 Thomas Brox INT J COMPUT VISION 6.085 ACM T INFORM SYST 5.059 BIOINFORMATICS 4.894 MIS QUART 4.731 IEEE T PATTERN ANAL 4.306 ACM COMPUT SURV 4.13 ACM T GRAPHIC 4.081 J AM MED INFORM ASSN 3.979 IEEE T EVOLUT COMPUT 3.77 IEEE T MED IMAGING 3.757 NEUROINFORMATICS 3.541 J CHEM INF MODEL 3.423 VLDB J 3.289 MED IMAGE ANAL 3.256 J ACM 2.917 J CRYPTOL 2.833 IEEE T IMAGE PROCESS 2.715 MACH LEARN 2.654 IEEE T NEURAL NETWOR 2.62 IEEE WIREL COMMUN 2.577 COGNITIVE BRAIN RES 2.568 IEEE T MOBILE COMPUT 2.55 CHEMOMETR INTELL LAB 2.45 IEEE INTELL SYST 2.413 HUM-COMPUT INTERACT 2.391 J MOL GRAPH MODEL 2.371 J BIOMED INFORM 2.346 J COMPUT PHYS 2.328 DATA MIN KNOWL DISC 2.295 IEEE ACM T COMPUT BI 2.283 ARTIF INTELL 2.271 J MACH LEARN RES 2.255 NEURAL COMPUT 2.229 IEEE NETWORK 2.211 ACM T DATABASE SYST 2.143 COMPUT BIOL CHEM 2.135 IEEE T SOFTWARE ENG 2.132 INFORM MANAGE-AMSTER 2.119 QUANTUM INF COMPUT 2.105 J COMPUT AID MOL DES 2.089 IEEE T KNOWL DATA EN 2.063 IEEE PERVAS COMPUT 2.062 J COMPUT BIOL 2 MATCH-COMMUN MATH CO 2 NEURAL NETWORKS 2 Impact factors of computer science journals 2006 20 Image Processing • • Quality control, visual inspection • • Fingerprint recognition Iris recognition Face recognition Tracking Medical systems • Entertainment industry – – – – 3D reconstruction Motion capturing Augmented reality Human-machine interaction • Driver assistance systems – Lane control – Collision avoidance – Autonomous driving • • – Autonomous robots (e.g. pathfinder) – Domestic robots • Artificial intelligence 21 Physics – Optics – Computational physics • Electrical engineering – Signal processing • Neuroscience – Neurophysiology – Computational neuroscience – Psychophysics Numerics Statistics Linear algebra Functional analysis Graph theory Geometric algebra • Medicine • Philosophy © 2007 Thomas Brox Image Processing Conferences and Journals • Mathematics – – – – – – Robotics Audio processing Pattern recognition Optimization Machine learning Data retrieval Computer graphics Robotics Control theory Software engineering 22 Overview (planned) Conferences – – – – – – – – • • Related sciences Computer science – – – – – – – – – Earth surveillance © 2007 Thomas Brox Image Processing • – Weather forecasts – Google Earth – Image enhancement – Data analysis – Routine diagnostics • Information systems – Document analysis – Image Google Security systems – – – – Image Processing Some image processing applications ICCV: ECCV: CVPR: NIPS: DAGM: ICIP: ICPR: SSVM: International Conference on Computer Vision European Conference on Computer Vision Int. Conference on Computer Vision and Pattern Recognition Neural Information Processing Systems Tagung der Deutschen Arbeitsgemeinschaft für Mustererkennung International Conference on Image Processing International Conference on Pattern Recognition Int. Conf. on Scale Space and Variational Methods • • • • • • • • • • • • • • Journals – – – – – – – – – International Journal of Computer Vision IEEE Transactions on Pattern Analysis and Machine Intelligence IEEE Transactions on Image Processing Computer Vision and Image Understanding Image and Vision Computing Journal of Mathematical Imaging and Vision Journal of Visual Communication and Image Representation Realtime Imaging Pattern Recognition © 2007 Thomas Brox 23 Class 1: Introduction Class 2: Image acquisition and representation Class 3: Noise, point operations Class 4: Fourier transform Class 5: Linear filters Class 6: Wavelets Class 7: Morphological filters Class 8: Nonlinear diffusion filters Class 9: Variational methods I Class 10: Variational methods II Class 11: Deconvolution Class 12: Texture analysis and filtering Class 13: Color spaces Continued next term with the course Computer Vision © 2007 Thomas Brox 24 Image Processing Image Processing Summary • Image processing, and particularly computer vision, are important research fields • Their importance grows rapidly with the number of successful applications • Image processing makes use of techniques from various other sciences • Especially mathematics provides many helpful tools © 2007 Thomas Brox 25 Literature • R. C. Gonzalez, R. E. Woods: Digital Image Processing, Addison-Wesley, Reading, 2nd Edition, 2002. • J. Bigün: Vision with Direction, Springer, Berlin, 2006. • K. D. Tönnies: Grundlagen der Bildverarbeitung (in German), Pearson Studium, Munich, 2005. • CV Online: Online compendium on numerous image processing and computer vision topics, http://homepages.inf.ed.ac.uk/rbf/CVonline/ © 2007 Thomas Brox 26