146 research outputs found

    Automated classification of cricket pitch frames in cricket video

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    The automated detection of the cricket pitch in a video recording of a cricket match is a fundamental step in content-based indexing and summarization of cricket videos. In this paper, we propose visualcontent based algorithms to automate the extraction of video frames with the cricket pitch in focus. As a preprocessing step, we first select a subset of frames with a view of the cricket field, of which the cricket pitch forms a part. This filtering process reduces the search space by eliminating frames that contain a view of the audience, close-up shots of specific players, advertisements, etc. The subset of frames containing the cricket field is then subject to statistical modeling of the grayscale (brightness) histogram (SMoG). Since SMoG does not utilize color or domain-specific information such as the region in the frame where the pitch is expected to be located, we propose an alternative algorithm: component quantization based region of interest extraction (CQRE) for the extraction of pitch frames. Experimental results demonstrate that, regardless of the quality of the input, successive application of the two methods outperforms either one applied exclusively. The SMoG-CQRE combination for pitch frame classification yields an average accuracy of 98:6% in the best case (a high resolution video with good contrast) and an average accuracy of 87:9% in the worst case (a low resolution video with poor contrast). Since, the extraction of pitch frames forms the first step in analyzing the important events in a match, we also present a post-processing step, viz. , an algorithm to detect players in the extracted pitch frames

    Multilevel Chinese takeaway process and label-based processes for rule induction in the context of automated sports video annotation

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    We propose four variants of a novel hierarchical hidden Markov models strategy for rule induction in the context of automated sports video annotation including a multilevel Chinese takeaway process (MLCTP) based on the Chinese restaurant process and a novel Cartesian product label-based hierarchical bottom-up clustering (CLHBC) method that employs prior information contained within label structures. Our results show significant improvement by comparison against the flat Markov model: optimal performance is obtained using a hybrid method, which combines the MLCTP generated hierarchical topological structures with CLHBC generated event labels. We also show that the methods proposed are generalizable to other rule-based environments including human driving behavior and human actions

    Multilevel Chinese takeaway process and label-based processes for rule induction in the context of automated sports video annotation

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    We propose four variants of a novel hierarchical hidden Markov models strategy for rule induction in the context of automated sports video annotation including a multilevel Chinese takeaway process (MLCTP) based on the Chinese restaurant process and a novel Cartesian product label-based hierarchical bottom-up clustering (CLHBC) method that employs prior information contained within label structures. Our results show significant improvement by comparison against the flat Markov model: optimal performance is obtained using a hybrid method, which combines the MLCTP generated hierarchical topological structures with CLHBC generated event labels. We also show that the methods proposed are generalizable to other rule-based environments including human driving behavior and human actions

    Anomaly Detection, Rule Adaptation and Rule Induction Methodologies in the Context of Automated Sports Video Annotation.

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    Automated video annotation is a topic of considerable interest in computer vision due to its applications in video search, object based video encoding and enhanced broadcast content. The domain of sport broadcasting is, in particular, the subject of current research attention due to its fixed, rule governed, content. This research work aims to develop, analyze and demonstrate novel methodologies that can be useful in the context of adaptive and automated video annotation systems. In this thesis, we present methodologies for addressing the problems of anomaly detection, rule adaptation and rule induction for court based sports such as tennis and badminton. We first introduce an HMM induction strategy for a court-model based method that uses the court structure in the form of a lattice for two related modalities of singles and doubles tennis to tackle the problems of anomaly detection and rectification. We also introduce another anomaly detection methodology that is based on the disparity between the low-level vision based classifiers and the high-level contextual classifier. Another approach to address the problem of rule adaptation is also proposed that employs Convex hulling of the anomalous states. We also investigate a number of novel hierarchical HMM generating methods for stochastic induction of game rules. These methodologies include, Cartesian product Label-based Hierarchical Bottom-up Clustering (CLHBC) that employs prior information within the label structures. A new constrained variant of the classical Chinese Restaurant Process (CRP) is also introduced that is relevant to sports games. We also propose two hybrid methodologies in this context and a comparative analysis is made against the flat Markov model. We also show that these methods are also generalizable to other rule based environments

    Semantic Analysis of High-definition MPEG-2 Soccer Video Using Bayesian Network

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    近年,インターネットのブロードバンド化に伴い,映像配信が普及し,また,地上デジタル放送や,BS・CSデジタル放送などの衛星放送により,ユーザが試聴できる番組の数が急増してきている.パソコンやレコーダのハードディスクの容量も増え,大量の番組(コンテンツ)を保存することが可能となったが,その反面,膨大な映像データの中から,視聴者の求めるシーンを素早く検索する技術の必要性がこれまでにも増して高まって来ている.本研究はサッカー映像のリプレーシーンとゴール付近のハイライトシーンの検出方法を提案する.シーンの検出には,MPEG-2エンコーダによって圧縮されたハイビジョンサッカー映像から抽出した特徴量とハイライトシーンとの間の因果関係をベイジアンネットワークで記述する手法を用いる.ベイジアンネットワークを用いることにより,抽出された特徴量からハイライトシーンの発生を確率的に推論することが可能になる.すでにベイジアンネットワークを用いたサッカー映像のハイライトシーンの検出法は提案されているが,それらの方法では,フレーム毎に画素単位でさまざまな画像処理を映像に施すことによって求めた特徴量を利用している.そのため,画面が大きくなると計算コストも大きくなるので,リアルタイム処理には専用の処理装置が必要になる.本研究で提案する方法はMPEG-2圧縮データに含まれている符号化パラメータから特徴量を計算するので,従来法に比べて計算量が少なく,ハイビジョンなどの高解像度映像であっても,通常のPCを用いてリアルタイム処理が可能である.また,従来法では各種シーンに対してベイジアンネットワークが提案されているが,いずれも,ネットワークモデル中のシーンに関わるイベントがすべてフレーム単位で定義されている.例えば,従来法のゴールシーンに関わる,ゴールゲートの出現,観客の声,リプレーの発生等のイベントは全てフレーム単位で数えている.しかし,各イベントの開始・終了フレームを明確に判定する手法が明らかにされておらず,場合によっては人の手で行わなう必要がある.そのため,ベイジアンネットワークを学習する時に、各種イベントの時間帯の与え方に誤差が含まれる可能性がある.さらに、テストビデオから,シーン検出する時,シーンの始終時間帯の検出も困難である.本研究の提案手法では,まず,MPEG-2圧縮データから直接抽出した符号化パラメータの特徴的な変化から,カメラの切り換えに伴う画面の切り替るカット点を検出し,隣接する二つのカット点間をショットとして定義する.さらに各ショットの特徴量を調べることにより,ショットをいくつかのイベントクラスに分類する.さらに,シーンをある特徴的なイベントの発生として捉えることにより,シーンの検出を行う.本手法では,各イベントの開始・終了時刻をショットのカット点によって明確に与えることができることができ,しかもMPEG-2圧縮データから自動的に求めることが可能である.提案方式の性能評価のために,実際のビデオデータを使用した検出実験を行ったところ,ゴール付近で起こるイベントシーンの再現率が86.17%,適合率90.76%,またリプレーシーンの再現率が81.00%, 適合率92.57%という検出結果が得られた.一方,従来法の検出結果では,同一のビデオデータではないが,ゴール付近で起こるイベントシーンの再現率71.1%,適合率89.8%であり,提案方式のほうが従来法に比べ,再現率,適合率ともに上回り,とくに再現率の向上が顕著である.以上のことより,提案法の有効性が確認された.電気通信大学201

    Learning from Teacher's Eye Movement: Expertise, Subject Matter and Video Modeling

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    How teachers' eye movements can be used to understand and improve education is the central focus of the present paper. Three empirical studies were carried out to understand the nature of teachers' eye movements in natural settings and how they might be used to promote learning. The studies explored 1) the relationship between teacher expertise and eye movement in the course of teaching, 2) how individual differences and the demands of different subjects affect teachers' eye movement during literacy and mathematics instruction, 3) whether including an expert's eye movement and hand information in instructional videos can promote learning. Each study looked at the nature and use of teacher eye movements from a different angle but collectively converge on contributions to answering the question: what can we learn from teachers' eye movements? The paper also contains an independent methodology chapter dedicated to reviewing and comparing methods of representing eye movements in order to determine a suitable statistical procedure for representing the richness of current and similar eye tracking data. Results show that there are considerable differences between expert and novice teachers' eye movement in a real teaching situation, replicating similar patterns revealed by past studies on expertise and gaze behavior in athletics and other fields. This paper also identified the mix of person-specific and subject-specific eye movement patterns that occur when the same teacher teaches different topics to the same children. The final study reports evidence that eye movement can be useful in teaching; by showing increased learning when learners saw an expert model's eye movement in a video modeling example. The implications of these studies regarding teacher education and instruction are discussed.PHDEducation & PsychologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/145853/1/yizhenh_1.pd
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