• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 57
  • 32
  • 5
  • 4
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 116
  • 40
  • 38
  • 38
  • 36
  • 23
  • 20
  • 19
  • 19
  • 19
  • 18
  • 17
  • 17
  • 16
  • 16
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Rozpoznání obličeje / Face Recognition

Vojáček, Cyril January 2014 (has links)
This thesis is about face detection and recognition from video. Main emphasis is on computational speed, so it can be used for a real-time processing. Begining of this work focus on different approaches for detection and object recognition. Afterwards is explained the main principle of methods used for the final application. Next part is about design and implementation of this methods and conclusion is about the testing results of designed application.
42

Ovládání počítače pomocí gest / Human-Machine Interface Based on Gestures

Charvát, Jaroslav January 2011 (has links)
Master's thesis "Human-Machine Interface Based on Gestures" depicts the theoretical background of the computer vision and gesture recognition. It describes more in detail different methods that were used to create the application. Practical part of this thesis consists of the description of the developed program and its functionality. Using this application, user should be able to control computer by gestures of both right and left hands and also his head. The program is primarily based on the skin detection that is followed by the recognition of palms and head gestures. There were used two essential methods for these actions, AdaBoost and PCA.
43

Real-time 2D Static Hand Gesture Recognition and 2D Hand Tracking for Human-Computer Interaction

Popov, Pavel Alexandrovich 11 December 2020 (has links)
The topic of this thesis is Hand Gesture Recognition and Hand Tracking for user interface applications. 3 systems were produced, as well as datasets for recognition and tracking, along with UI applications to prove the concept of the technology. These represent significant contributions to resolving the hand recognition and tracking problems for 2d systems. The systems were designed to work in video only contexts, be computationally light, provide recognition and tracking of the user's hand, and operate without user driven fine tuning and calibration. Existing systems require user calibration, use depth sensors and do not work in video only contexts, or are computationally heavy requiring GPU to run in live situations. A 2-step static hand gesture recognition system was created which can recognize 3 different gestures in real-time. A detection step detects hand gestures using machine learning models. A validation step rejects false positives. The gesture recognition system was combined with hand tracking. It recognizes and then tracks a user's hand in video in an unconstrained setting. The tracking uses 2 collaborative strategies. A contour tracking strategy guides a minimization based template tracking strategy and makes it real-time, robust, and recoverable, while the template tracking provides stable input for UI applications. Lastly, an improved static gesture recognition system addresses the drawbacks due to stratified colour sampling of the detection boxes in the detection step. It uses the entire presented colour range and clusters it into constituent colour modes which are then used for segmentation, which improves the overall gesture recognition rates. One dataset was produced for static hand gesture recognition which allowed for the comparison of multiple different machine learning strategies, including deep learning. Another dataset was produced for hand tracking which provides a challenging series of user scenarios to test the gesture recognition and hand tracking system. Both datasets are significantly larger than other available datasets. The hand tracking algorithm was used to create a mouse cursor control application, a paint application for Android mobile devices, and a FPS video game controller. The latter in particular demonstrates how the collaborating hand tracking can fulfill the demanding nature of responsive aiming and movement controls.
44

Digitalizace historických map / Ancient Maps Digitizing

Pospíšil, Josef January 2008 (has links)
This work is about processing of historical maps, especially their digitizing and vectorization. The main focuses of this project are maps from the second historical military mapping and finding methods useful for removing texts from these maps.
45

Rozpoznání vzorů v obraze pomocí klasifikátorů / Pattern Recognition in Image Using Classifiers

Juránek, Roman Unknown Date (has links)
An AdaBoost algorithm for construction of strong classifier from several weak hypotesis will be presented in this work. Theoretical background of the algorithm and the method of construction of strong classifiers will be explained. WaldBoost extension to the algorithm will be described. The thesis deals with image features that are often used as element of weak classifiers. Brief introduction to pattern recognition in context of computer vision will be outlined in the begining of the work. Also some widely used methods of classifier training will be presented. An object detection library based on AdaBoost classifiers was developed as part of the work. The library was used in implementation of software that in praktice demonstrates object detection in videosquences. Last part of the work describes tool for training of AdaBoost classifiers.
46

Sdílení lokální informace pro rychlejší detekci objektů / Sharing Local Information for Faster Scanning-Window Object Detection

Hradiš, Michal January 2014 (has links)
Cílem této dizertační prace je vylepšit existující detektory objektů pomocí sdílení informace a výpočtů mezi blízkými pozicemi v obraze. Navrhuje dvě metody, které jsou založené na Waldově sekvenčním testu poměrem pravděpodobností a algoritmu WaldBoost. První z nich, Early non-Maxima Suppression , přesunuje rozhodování o potlačení nemaximálních pozic ze závěrečné fáze do fáze vyhodnocování detektoru, čímž zamezuje zbytečným výpočtům detektoru v nemaximálních pozicích. Metoda neighborhood suppression doplňuje existující detektory o schopnost zavrhnout okolní pozice v obraze. Navržené metody je možné aplikovat na širokou škálu detektorů. Vyhodnocení obou metod dokazují jejich výrazně vyšší efektivitu v porovnání s detektory, které vyhodnocují jednotlivé pozice obrazu zvlášť. Dizertace navíc prezentuje výsledky rozsáhlých experimentů, jejichž cílem bylo vyhodnotit vlastnosti běžných obrazových příznaků v několika detekčních úlohách a situacích.
47

Akcelerace detekce objektů pomocí klasifikátorů / Acceleration of Object Detection Using Classifiers

Juránek, Roman January 2012 (has links)
Detekce objektů v počítačovém vidění je složítá úloha. Velmi populární a rozšířená metoda pro detekci je využití statistických klasifikátorů a skenovacích oken. Pro učení kalsifikátorů se často používá algoritmus AdaBoost (nebo jeho modifikace), protože dosahuje vysoké úspěšnosti detekce, nízkého počtu chybných detekcí a je vhodný pro detekci v reálném čase. Implementaci detekce objektů je možné provést různými způsoby a lze využít vlastnosti konkrétní architektury, pro urychlení detekce. Pro akceleraci je možné využít grafické procesory, vícejádrové architektury, SIMD instrukce, nebo programovatelný hardware. Tato práce představuje metodu optimalizace, která vylepšuje výkon detekce objektů s ohledem na cenovou funkci zadanou uživatelem. Metoda rozděluje předem natrénovaný klasifikátor do několika různých implementací, tak aby celková cena klasifikace byla minimalizována. Metoda je verifikována na základním experimentu, kdy je klasifikátor rozdělen do předzpracovací jednotku v FPGA a do jednotky ve standardním PC.
48

Feature Construction Using Evolution-COnstructed Features for General Object Recognition

Lillywhite, Kirt D. 05 March 2012 (has links) (PDF)
Object recognition is a well studied but extremely challenging field. Human detection is an especially important part of object recognition as it has played a role in machine and human interaction, biometrics, unmanned vehicles, as well as tracking and surveillance. We first present a hardware implementation of the successful Histograms of Oriented Gradients (HOG) method for human detection. The implementation significantly speeds up the method achieving 38 frames a second on VGA video while testing 11,160 sliding windows per frame. The accuracy remains comparable to the CPU implementation. Analysis of the HOG method and other popular object recognition methods led to a novel approach for object detection using a feature construction method called Evolution-COnstructed (ECO) features. Most other approaches rely on human experts to construct features for object recognition. ECO features are automatically constructed by uniquely employing a standard genetic algorithm to discover series of transforms that are highly discriminative. Using ECO features provides several advantages over other object detection algorithms including: no need for a human expert to build feature sets or tune their parameters, ability to generate specialized feature sets for different objects, and no limitations to certain types of image sources. We show in our experiments that ECO features perform better or comparable with state-of-the-art object recognition algorithms making it the first feature construction method to compete with features created by human experts at general object recognition. An analysis is given of ECO features which includes a visualization of ECO features and improvements made to the algorithm.
49

Detecting early-stage Alzheimer’s disease with Machine Learning algorithms

Mukka, Jakob January 2023 (has links)
Alzheimer’s disease (AD) accounts for the majority of all cases of dementia and can be characterized as a disease that causes a progressive decline of cognitive functions. Detecting the disease at it’s earliest stage is important as medical treatments can be more effective if they can be applied before the disease has caused irreparable brain damage. However, making a correct diagnosis of AD can be difficult, especially in the early stage when the symptoms are still mild. Machine learning algorithms can help in this process, with the purpose of this study being to investigate just how accurately machine learning algorithms can detect early-stage AD. Three algorithms were selected for the study, Random Forest, AdaBoost and Logistic Regression, which were then evaluated on the accuracy of their predictions. The results showed that Random Forest had the best overall performance with an accuracy of 79.78%. AdaBoost attained an accuracy of 76.40% and Logistic Regression attained an accuracy of 74.16%. These results suggest that machine learning algorithms can be used to make relatively accurate predictions of AD even when the disease is in it’s early stage.
50

Predicting the Options Expiration Effect Using Machine Learning Models Trained With Gamma Exposure Data / Prediktion av inverkan på aktiemarknaden då optioner upphör med hjälp av maskininlärningsmodeller tränade med dagliga GEX värden

Dubois, Alexander January 2022 (has links)
The option expiration effect is a well-studied phenome, however, few studies have implemented machine learning models to predict the effect on the underlying stock market due to options expiration. In this paper four machine learning models, SVM, random forest, AdaBoost, and LSTM, are evaluated on their ability to predict whether the underlying index rises or not on the day of option expiration. The options expiration effect is mainly driven by portfolio rebalancing made by market makers who aim to maintain delta-neutral portfolios. Whether or not market makers need to rebalance their portfolios depend on at least two variables; gamma and open interest. Hence, the machine learning models in this study use gamma exposure (i.e. a combination of gamma and open interest) to predict the options expiration effect. Furthermore, four architectures of LSTM are implemented and evaluated. The study shows that a three-layered many-to-one LSTM model achieves superior results with an F1 score of 62%. However, none of the models achieved better predictions than a model that predicts only positive classes. Some of the problems regarding gamma exposure are discussed and possible improvements for future studies are given. / Flera studier har visat att optionsmarknaden påverkar aktiemarknaden, speciellt vid optioners utgångsdatum. Dock har få studier undersökt maskininlärningsmodellers förmåga att förutse denna effekt. I den här studien, implementeras och utvärderas fyra olika maskininlärningsmodeller, SVM, random forest, AdaBoost, och LSTM, med syftet att förutse om den underliggande aktiemarknaden stiger vid optioners utgångsdatum. Att optionsmarknaden påverkar aktiemarknaden vid optioners utgångsdatum beror på att market makers ombalanserar sina portföljer för att bibehålla en delta-neutral portfölj. Market makers behov av att ombalansera sina portföljer beror på åtminstone två variabler; gamma och antalet aktiva optionskontrakt. Därmed använder maskininlärningsmodellerna i denna studie GEX, som är en kombination av gamma och antalet aktiva optionskontrakt, med syftet att förutse om marknaden stiger vid optioners utgångsdatum. Vidare implementeras och utvärderas fyra olika varianter av LSTM modeller. Studien visar att en many-to-one LSTM modell med tre lager uppnådde bäst resultat med ett F1 score på 62%. Dock uppnådde ingen av modellerna bättre resultat än en modell som predicerar endast positiva klasser. Avslutningsvis diskuteras problematiken med att använda GEX och rekommendationer för framtida studier ges.

Page generated in 0.0392 seconds