107,466 research outputs found

    Observation-driven adaptive differential evolution and its application to accurate and smooth bronchoscope three-dimensional motion tracking

    Full text link
    © 2015 Elsevier B.V. This paper proposes an observation-driven adaptive differential evolution algorithm that fuses bronchoscopic video sequences, electromagnetic sensor measurements, and computed tomography images for accurate and smooth bronchoscope three-dimensional motion tracking. Currently an electromagnetic tracker with a position sensor fixed at the bronchoscope tip is commonly used to estimate bronchoscope movements. The large tracking error from directly using sensor measurements, which may be deteriorated heavily by patient respiratory motion and the magnetic field distortion of the tracker, limits clinical applications. How to effectively use sensor measurements for precise and stable bronchoscope electromagnetic tracking remains challenging. We here exploit an observation-driven adaptive differential evolution framework to address such a challenge and boost the tracking accuracy and smoothness. In our framework, two advantageous points are distinguished from other adaptive differential evolution methods: (1) the current observation including sensor measurements and bronchoscopic video images is used in the mutation equation and the fitness computation, respectively and (2) the mutation factor and the crossover rate are determined adaptively on the basis of the current image observation. The experimental results demonstrate that our framework provides much more accurate and smooth bronchoscope tracking than the state-of-the-art methods. Our approach reduces the tracking error from 3.96 to 2.89. mm, improves the tracking smoothness from 4.08 to 1.62. mm, and increases the visual quality from 0.707 to 0.741

    Selected topics in video coding and computer vision

    Get PDF
    Video applications ranging from multimedia communication to computer vision have been extensively studied in the past decades. However, the emergence of new applications continues to raise questions that are only partially answered by existing techniques. This thesis studies three selected topics related to video: intra prediction in block-based video coding, pedestrian detection and tracking in infrared imagery, and multi-view video alignment.;In the state-of-art video coding standard H.264/AVC, intra prediction is defined on the hierarchical quad-tree based block partitioning structure which fails to exploit the geometric constraint of edges. We propose a geometry-adaptive block partitioning structure and a new intra prediction algorithm named geometry-adaptive intra prediction (GAIP). A new texture prediction algorithm named geometry-adaptive intra displacement prediction (GAIDP) is also developed by extending the original intra displacement prediction (IDP) algorithm with the geometry-adaptive block partitions. Simulations on various test sequences demonstrate that intra coding performance of H.264/AVC can be significantly improved by incorporating the proposed geometry adaptive algorithms.;In recent years, due to the decreasing cost of thermal sensors, pedestrian detection and tracking in infrared imagery has become a topic of interest for night vision and all weather surveillance applications. We propose a novel approach for detecting and tracking pedestrians in infrared imagery based on a layered representation of infrared images. Pedestrians are detected from the foreground layer by a Principle Component Analysis (PCA) based scheme using the appearance cue. To facilitate the task of pedestrian tracking, we formulate the problem of shot segmentation and present a graph matching-based tracking algorithm. Simulations with both OSU Infrared Image Database and WVU Infrared Video Database are reported to demonstrate the accuracy and robustness of our algorithms.;Multi-view video alignment is a process to facilitate the fusion of non-synchronized multi-view video sequences for various applications including automatic video based surveillance and video metrology. In this thesis, we propose an accurate multi-view video alignment algorithm that iteratively aligns two sequences in space and time. To achieve an accurate sub-frame temporal alignment, we generalize the existing phase-correlation algorithm to 3-D case. We also present a novel method to obtain the ground-truth of the temporal alignment by using supplementary audio signals sampled at a much higher rate. The accuracy of our algorithm is verified by simulations using real-world sequences

    Tracking Different Ant Species: An Unsupervised Domain Adaptation Framework and a Dataset for Multi-object Tracking

    Full text link
    Tracking individuals is a vital part of many experiments conducted to understand collective behaviour. Ants are the paradigmatic model system for such experiments but their lack of individually distinguishing visual features and their high colony densities make it extremely difficult to perform reliable tracking automatically. Additionally, the wide diversity of their species' appearances makes a generalized approach even harder. In this paper, we propose a data-driven multi-object tracker that, for the first time, employs domain adaptation to achieve the required generalisation. This approach is built upon a joint-detection-and-tracking framework that is extended by a set of domain discriminator modules integrating an adversarial training strategy in addition to the tracking loss. In addition to this novel domain-adaptive tracking framework, we present a new dataset and a benchmark for the ant tracking problem. The dataset contains 57 video sequences with full trajectory annotation, including 30k frames captured from two different ant species moving on different background patterns. It comprises 33 and 24 sequences for source and target domains, respectively. We compare our proposed framework against other domain-adaptive and non-domain-adaptive multi-object tracking baselines using this dataset and show that incorporating domain adaptation at multiple levels of the tracking pipeline yields significant improvements. The code and the dataset are available at https://github.com/chamathabeysinghe/da-tracker

    Adaptive online performance evaluation of video trackers

    Full text link
    Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. J. C. SanMiguel, A. Caballaro, and J. M. Martínez, "Adaptive Online Performance Evaluation of Video Trackers", IEEE Transactions on Image Processing, vol. 21, no. 5, pp. 2812 - 2823. May 2012We propose an adaptive framework to estimate the quality of video tracking algorithms without ground-truth data. The framework is divided into two main stages, namely, the estimation of the tracker condition to identify temporal segments during which a target is lost and the measurement of the quality of the estimated track when the tracker is successful. A key novelty of the proposed framework is the capability of evaluating video trackers with multiple failures and recoveries over long sequences. Successful tracking is identified by analyzing the uncertainty of the tracker, whereas track recovery from errors is determined based on the time-reversibility constraint. The proposed approach is demonstrated on a particle filter tracker over a heterogeneous data set. Experimental results show the effectiveness and robustness of the proposed framework that improves state-of-the-art approaches in the presence of tracking challenges such as occlusions, illumination changes, and clutter and on sequences containing multiple tracking errors and recoveries.This work was partially supported by the Spanish Government (TEC2007- 65400 SemanticVideo), Cátedra Infoglobal-UAM for “Nuevas Tecnologías de video aplicadas a la seguridad”, Consejería de Educación of the Comunidad de Madrid and European Social Fund

    PENERAPAN OBJECT TRACKING DENGAN METODE ADAPTIVE PARTICLE FILTER UNTUK PELACAKAN BOLA PADA PERMAINAN

    Get PDF
    Data pergerakan bola dapat dimanfaatkan sebagai panduan untuk mengamati kejadian-kejadian pada pertandingan tenis yang telah berlangsung. Namun, untuk mendapatkan data pergerakan bola dari video pertandingan rentan terjadi kesalahan dalam pendeteksian objek, sehingga data yang dihasilkan terdapat noise. Berdasarkan alasan tesebut, penulis melakukan mining terhadap video pertandingan bola tenis dengan pendekatan object tracking, sehingga kesalahan deteksi ketika mendeteksi bola dapat dikurangi. Pendekatan tersebut diwujudkan dengan merancang model pelacakan bola dengan metode circle hough transform untuk mendeteksi lingkaran, kemudian dilanjutkan dengan metode pelacakan adaptive particle filter yang berfungsi untuk menghilangkan noise yang dihasilkan ketika melakukan deteksi lingkaran. Model tersebut dijalankan melalui proses-proses yang diantaranya adalah segmentasi citra, deteksi lingkaran, pelacakan objek dan diakhiri dengan koreksi lintasan. Model yang dirancang kemudian diimplementasikan pada bahasa pemrograman Phyton dan library OpenCV. Tahap terakhir dalam penelitian ini adalah melakukan eksperimen, eksperimen ini bertujuan untuk mendapatkan parameter masukan terbaik pada perangkat lunak, sehingga dapat diketahui efektifitas dari model yang telah diimplementasikan. Hasil eksperimen menunjukan bahwa video dengan jenis siaran pada lapangan hard court outdoor menghasilkan keluaran terbaik dengan rata-rata error sebesar 0,344, sedangkan hasil pengujian pada parameter lainnya harus disesuaikan dengan jenis video masukan agar mendapat error minimal.----------Ball movement data can be utilized as a guide for observing the events on the tennis matches that has lasted. However, the movement of the ball to get the data from the video game of the vulnerable object detection in error, so that the resulting data there is noise. Based on the reasons are, the author does mining against video game tennis ball with object tracking approach, so the error detection when it detects the ball can be reduced. The approach embodied by designing a model tracking ball with hough transform for circle method to detect circles, then proceed with adaptive particle filter tracking method that serves to eliminate noise generated when the detection loop. The model is run through processes such as image segmentation, object tracking, circle detection and end with correction trajectory. Model designed then implemented in the programming language Python and OpenCV library. The last stage in this research is doing experiments, this experiment aims to get the best input parameters in the software, so it can be known to the effectiveness of the model that has been implemented. Experimental results show that the type of video broadcast on an outdoor hard court field produce the best output with an average error of 0.344, whereas the test results on the other parameters must be adjusted to the type of video input so that it gets the error minimal
    corecore