Decision Tree Design Based on Evolutionary Algorithms

Tato diplomová práce pojednává o dvou algoritmech pro dolování z proudu dat - Very Fast Decision Tree (VFDT) a Concept-adapting Very Fast Decision Tree (CVFDT). Je vysvětlen princip klasifikace rozhodovacím stromem. Je popsána základní myšlenka konstrukce stromu Hoeffding Tree, který je základem pro algoritmy VFDT a CVFDT. Tyto algoritmy jsou poté rozebrány detailněji. Dále se tato práce zabývá návrhem algoritmu Genetického Programování (GP), který je použit pro vytváření klasifikátoru obrazových dat. Vytvořený klasifikátor je použit jako alternativní způsob klasifikace objektů v obraze ve frameworku Viola-Jones. V práci je rozebrána implementace algoritmů, které jsou implementovány v jazyce Java. Algoritmus GP je integrován do knihovny “Image Processing Extension” programu RapidMiner. Algoritmy VFDT a CVFDT jsou testovány na syntetických a reálných textových datech. Algoritmus GP je testován na klasifikaci obrazových dat a následně vytvořený klasifikátor je otestován na detekci obličejů v obraze.This thesis deals with two algorithms for data stream mining - the Very Fast Decision Tree (VFDT) and the Concept-adapting Very Fast Decision Tree (CVFDT). The decision tree based classification is explained. The essential idea of the Hoeffding Tree, which is the base of VFDT and CVFDT algorithms is described. Both algorithms VFDT and CVFDT are explained in more detail. Further this work deals with the design of the Genetic Programming algorithm, which is used for an image object classifier evolving. This classifier is used as alternative approach of object classification in the Viola-Jones framework. All algorithms are implemented in programming language Java. The implementation is described. The algorithm GP is integrated into the “Image Processing Extension” library of the program RapidMiner. The VFDT and CVFDT are tested on the synthetic and real text data. The GP algorithm is tested on the image data for the object classification. The evolved classifier is tested on the object in image detection.

On the classifier performance for simulation based debris detection in sar imagery

Urban areas struck by disasters such as earthquakes are in need of a fast damage detection assessment. A post-event SAR image often is the first available image, most likely with no matching pre-event image to perform change detection. In previous work we have introduced a debris detection algorithm for this scenario that is trained exclusively with synthetically generated training data. A classification step is employed to separate debris from similar textures such as vegetation. In order to verify the use of a random forest classifier for this context, we conduct a performance comparison with two alternative popular classifiers, a support vector machine and a convolutional neural network. With the direct comparison revealing the random forest classifier to be best suited, the effective performance on the prospect of debris detection is investigated for the post-earthquake Christchurch scene. Results show a good separation of debris from vegetation and gravel, thus reducing the false alarm rate in the damage detection operation considerably

Real-time human action recognition on an embedded, reconfigurable video processing architecture

Copyright @ 2008 Springer-Verlag.In recent years, automatic human motion recognition has been widely researched within the computer vision and image processing communities. Here we propose a real-time embedded vision solution for human motion recognition implemented on a ubiquitous device. There are three main contributions in this paper. Firstly, we have developed a fast human motion recognition system with simple motion features and a linear Support Vector Machine (SVM) classifier. The method has been tested on a large, public human action dataset and achieved competitive performance for the temporal template (eg. “motion history image”) class of approaches. Secondly, we have developed a reconfigurable, FPGA based video processing architecture. One advantage of this architecture is that the system processing performance can be reconfiured for a particular application, with the addition of new or replicated processing cores. Finally, we have successfully implemented a human motion recognition system on this reconfigurable architecture. With a small number of human actions (hand gestures), this stand-alone system is performing reliably, with an 80% average recognition rate using limited training data. This type of system has applications in security systems, man-machine communications and intelligent environments.DTI and Broadcom Ltd

Wavelet frame accelerated reduced vector machine for efficient image analysis

We propose a new approach for face and facial feature detection combined with the advantages of the Morphable Model. The presented method reduces the runtime complexity of a Support Vector Machine classifier and the new training algorithm is fast and simple. This is achieved by an Over-Complete Wavelet Transform that finds optimally sparse approximations of the Support Set Vectors. The wavelet-based approach provides an upper bound on the distance between the decision function of the Support Vector Machine and our classifier. The obtained classifier is fast since the used Haar wavelet approximations of the Support Set Vectors allow efficient Integral Image-based kernel evaluations. This provides a set of double-cascaded classifiers of increasing accuracy for an early rejection. The algorithm yields an excellent runtime performance that is achieved by hierarchically discriminating with respect to the number and approximation accuracy of incorporated Reduced Set Vectors. The proposed algorithm is applied to the problem of face and facial feature detection, but it can also be used for other image-based classifications. The algorithm presented, provides a 530-fold speed-up over the Support Vector Machine, enabling face detection at more than 25 fps on a standard PC. Summarizing, we propose very fast and efficient to train classifiers that improve the detection performance by involving the advantages of the Morphable Model. On one hand to improve the fitting algorithm of the Morphable Model by automatic anchor point detection and on the other hand to use the Morphable Model for improving the training by synthetic data sets and to reduced the False Acceptance Rate