Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-06-07T14:26:02Z No. of bitstreams: 1 helenadealmeidamaia.pdf: 3132814 bytes, checksum: d46a470b453ec6ba11362abaeac3a42c (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-06-07T14:56:50Z (GMT) No. of bitstreams: 1 helenadealmeidamaia.pdf: 3132814 bytes, checksum: d46a470b453ec6ba11362abaeac3a42c (MD5) / Made available in DSpace on 2017-06-07T14:56:50Z (GMT). No. of bitstreams: 1 helenadealmeidamaia.pdf: 3132814 bytes, checksum: d46a470b453ec6ba11362abaeac3a42c (MD5) Previous issue date: 2016-03-18 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Nos últimos anos, o rastreador TLD (Tracking-Learning-Detection) se destacou por combinar um método de rastreamento através do movimento aparente e um método de detecção para o problema de rastreamento de objetos em vídeos. O detector identifica o objeto pelas aparências supostamente confirmadas. O rastreador insere novas aparências no modelo do detector estimando o movimento aparente. A integração das duas respostas é realizada através da mesma métrica de similaridade utilizada pelo detector que pode levar a uma decisão enviesada. Neste trabalho, é proposto um framework para métodos baseados em múltiplos rastreadores onde o componente responsável pela integração das respostas é independente dos rastreadores. Este componente é denominado mediador. Seguindo este framework, um novo método é proposto para integrar o rastreador por movimento e o detector do rastreador TLD pela combinação das suas estimativas. Os resultados mostram que, quando a integração é independente das métricas de ambos os rastreadores, a performance é melhorada para objetos com significativas variações de aparência durante o vídeo. / On the problem of tracking objects in videos, a recent and distinguished approach combining tracking and detection methods is the TLD (Tracking-Learning-Detection) framework. The detector identifies the object by its supposedly confirmed appearances. The tracker inserts new appearances into the model using apparent motion. Their outcomes are integrated by using the same similarity metric of the detector which, in our point of view, leads to biased results. In our work, we propose a framework for generic multitracker methods where the component responsible for the integration is independent from the trackers. We call this component as mediator. Using this framework, we propose a new method for integrating the motion tracker and detector from TLD by combining their estimations. Our results show that when the integration is independent of both tracker/detector metrics, the overall tracking is improved for objects with high appearance variations throughout the video.

Automatic tracking of an object of interest in a video sequence is a task that has been much researched. Difficulties include varying scale of the object, rotation and object appearance changing over time, thus leading to tracking failures. Different tracking methods, such as short-term tracking often fail if the object steps out of the camera’s field of view, or changes shape rapidly. Also, small inaccuracies in the tracking method can accumulate over time, which can lead to tracking drift. Long-term tracking is also problematic, partly due to updating and degradation of the object model, leading to incorrectly classified and tracked objects. This master’s thesis implements a long-term tracking framework called Tracking-Learning-Detection which can learn and adapt, using so called P/N-learning, to changing object appearance over time, thus making it more robust to tracking failures. The framework consists of three parts; a tracking module which follows the object from frame to frame, a learning module that learns new appearances of the object, and a detection module which can detect learned appearances of the object and correct the tracking module if necessary. This tracking framework is evaluated on thermal infrared videos and the results are compared to the results obtained from videos captured within the visible spectrum. Several important differences between visual and thermal infrared tracking are presented, and the effect these have on the tracking performance is evaluated. In conclusion, the results are analyzed to evaluate which differences matter the most and how they affect tracking, and a number of different ways to improve the tracking are proposed.