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This paper is a postprint of a paper submitted to and accepted for publication in Electronics Letters and is subject to Institution of Engineering and Technology Copyright. The copy of record is available at IEEE Digital Library ; A novel approach is proposed for online evaluation of video tracking without ground-truth data. The temporal evolution of the covariance features is exploited to detect the stability of the tracker output over time. A model validation strategy performs such detection without learning the failure cases of the tracker under evaluation. Then, the tracker performance is estimated by a finite state machine determining whether the tracker is on-target (successful) or not (unsuccessful). The experimental results over a heterogeneous dataset show that the proposed approach outperforms related state-of-the-art approaches in terms of performance and computational cost. ; This work was supported by the Spanish Government (TEC2011-25995, EventVideo).

This paper is a postprint of a paper submitted to and accepted for publication in Electronics Letters and is subject to Institution of Engineering and Technology Copyright. The copy of record is available at IEEE Digital Library ; A novel approach for part-based people detection in images that uses contextual information is proposed. Two sources of context are distinguished regarding the local (neighbour) information and the relative importance of the parts in the model. Local context determines part visibility which is derived from the spatial location of static objects in the scene and from the relation between scales of analysis and detection window sizes. Experimental results over various datasets show that the proposed use of context outperforms the related state-of-the-art. ; This work was supported by the Spanish Government (HA-Video TEC2014-5317-R).

The final publication is available at Springer via http://dx.doi.org/10.1007/s00138-011-0397-x ; This paper presents a distributed and scalable framework for video analysis that automatically estimates the optimal workflow required for the analysis of different application domains. It integrates several technologies related with data acquisition, visual analysis tools, communication protocols, and data storage. Moreover, hierarchical semantic representations are included in the framework to describe the application domain, the analysis capabilities, and the user preferences. The automatic determination of the analysis workflow is performed by selecting the most appropriate tools for each domain among the available ones in the framework by means of exploiting the relations between the semantic descriptions. The experimental results in the video surveillance domain demonstrate that the proposed approach successfully composes optimal workflows for video analysis applications. ; This work has been partially supported by the Spanish Government (TEC2011-25995), by the Consejería de Educación of the Comunidad de Madrid and by The European Social Fund.

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. San Miguel, and J. M. Martínez, "Robust unattended and stolen object detection by fusing simple algorithms", in IEEE Fifth International Conference on Advanced Video and Signal Based Surveillance, 2008. AVSS '08, 2008, p. 18 - 25 ; In this paper a new approach for detecting unattended or stolen objects in surveillance video is proposed. It is based on the fusion of evidence provided by three simple detectors. As a first step, the moving regions in the scene are detected and tracked. Then, these regions are classified as static or dynamic objects and human or nonhuman objects. Finally, objects detected as static and nonhuman are analyzed with each detector. Data from these detectors are fused together to select the best detection hypotheses. Experimental results show that the fusion-based approach increases the detection reliability as compared to the detectors and performs considerably well across a variety of multiple scenarios operating at realtime. ; This work is supported by Cátedra Infoglobal-UAM for "Nuevas Tecnologías de video aplicadas a la seguridad", by the Spanish Government (TEC2007-65400 SemanticVideo), by the Comunidad de Madrid (S- 050/TIC-0223 - ProMultiDis-CM), by the Consejería de Educación of the Comunidad de Madrid and by the European Social Fund.

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. San Miguel, and J. M. Martínez, "On the evaluation of background subtraction algorithms without ground-truth" in 2013 10th IEEE International Conference on Advanced Video and Signal Based Surveillance, 2013, 180 - 187 ; In video-surveillance systems, the moving object segmentation stage (commonly based on background subtraction) has to deal with several issues like noise, shadows and multimodal backgrounds. Hence, its failure is inevitable and its automatic evaluation is a desirable requirement for online analysis. In this paper, we propose a hierarchy of existing performance measures not-based on ground-truth for video object segmentation. Then, four measures based on color and motion are selected and examined in detail with different segmentation algorithms and standard test sequences for video object segmentation. Experimental results show that color-based measures perform better than motion-based measures and background multimodality heavily reduces the accuracy of all obtained evaluation results. ; This work is partially supported by the Spanish Government (TEC2007- 65400 SemanticVideo), by Cátedra Infoglobal-UAM for "Nuevas Tecnologías de video aplicadas a la seguridad", by the Consejería de Educación of the Comunidad de Madrid and by the European Social Fund.

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, and J. M. Martínez, "Shadow detection in video surveillance by maximizing agreement between independent detectors", in 16th IEEE International Conference on Image Processing, ICIP 2009. p. 1141-1144 ; This paper starts from the idea of automatically choosing the appropriate thresholds for a shadow detection algorithm. It is based on the maximization of the agreement between two independent shadow detectors without training data. Firstly, this shadow detection algorithm is described and then, it is adapted to analyze video surveillance sequences. Some modifications are introduced to increase its robustness in generic surveillance scenarios and to reduce its overall computational cost (critical in some video surveillance applications). Experimental results show that the proposed modifications increase the detection reliability as compared to some previous shadow detection algorithms and performs considerably well across a variety of multiple surveillance scenarios. ; Work supported by the Spanish Government (TEC2007- 65400 SemanticVideo), by Cátedra Infoglobal-UAM for "Nuevas Tecnologías de video aplicadas a la seguridad", by the Spanish Administration agency CDTI (CENIT-VISION 2007-1007), by the Comunidad de Madrid (S-050/TIC-0223 - ProMultiDis), by the Consejería de Educación of the Comunidad de Madrid and by the European Social Fund.

Proceedings of the 26th Picture Coding Symposium, PCS 2007, Lisbon, Portugal, November 2007 ; This paper presents a system to transmit the information from a static surveillance camera in an adaptive way, from low to higher bit-rate, based on the on-line generation of descriptions. The proposed system is based on a server/client model: the server is placed in the surveillance area and the client is placed in a user side. The server analyzes the video sequence to detect the regions of activity (motion analysis) and the corresponding descriptions (mainly MPEG-7 moving regions) are generated together with the textures of moving regions and the associated background image. Depending on the available bandwidth, different levels of transmission are specified, ranging from just sending the descriptions generated to a transmission with all the associated images corresponding to the moving objects and background. ; This work is partially supported by Cátedra Infoglobal-UAM para Nuevas Tecnologías de video aplicadas a la seguridad. This work is also supported by the Ministerio de Ciencia y Tecnología of the Spanish Government under project TIN2004-07860 (MEDUSA) and by the Comunidad de Madrid under project P-TIC-0223-0505 (PROMULTIDIS).

This paper is a postprint of a paper submitted to and accepted for publication in 3rd International Conference on Imaging for Crime Detection and Prevention (ICDP 2009), and is subject to Institution of Engineering and Technology Copyright. The copy of record is available at IET Digital Library and IEEE Xplore ; In this paper we describe how the knowledge related to a specific domain and the available visual analysis tools can be used to create dynamic visual analysis systems for video surveillance. Firstly, the knowledge is described in terms of application domain (types of objects, events. that can appear in such domain) and system capabilities (algorithms, detection procedures.) by using an existing ontology. Secondly, the ontology is integrated into a framework to create the visual analysis systems for each domain by inspecting the relations between the entities defined in the domain and system knowledge. Additionally, when necessary, analysis tools could be added or removed on-line. Experiments/Application of the framework show that the proposed approach for creating dynamic visual analysis systems is suitable for analyzing different video surveillance domains without decreasing the overall performance in terms of computational time or detection accuracy. ; This work was partially supported by the Spanish Administration agency CDTI (CENIT-VISION 2007-1007), by the Spanish Government (TEC2007- 65400 SemanticVideo), by the Comunidad de Madrid (S-050/TIC-0223 - ProMultiDis), by Cátedra Infoglobal-UAM for "Nuevas Tecnologías de video aplicadas a la seguridad", by the Consejería de Educación of the Comunidad de Madrid and by The European Social Fund.

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. San Miguel, and J. M. Martínez, "On the effect of motion segmentation techniques in description based adaptive video transmission", in AVSS '07: Proceedings of the 2007 IEEE Conference on Advanced Video and Signal Based Surveillance, 2007, p. 359-364 ; This paper presents the results of analysing the effect of different motion segmentation techniques in a system that transmits the information captured by a static surveillance camera in an adaptative way based on the on-line generation of descriptions and their descriptions at different levels of detail. The video sequences are analyzed to detect the regions of activity (motion analysis) and to differentiate them from the background, and the corresponding descriptions (mainly MPEG-7 moving regions) are generated together with the textures of the moving regions and the associated background image. Depending on the available bandwidth, different levels of transmission are specified, ranging from just sending the descriptions generated to a transmission with all the associated images corresponding to the moving objects and background. We study the effect of three motion segmentation algorithms in several aspects such as accurate segmentation, size of the descriptions generated, computational efficiency and reconstructed data quality. ; This work is partially supported by Cátedra Infoglobal-UAM para Nuevas Tecnologías de video aplicadas a la seguridad. This work is also supported by the Ministerio de Ciencia y Tecnología of the Spanish Government under project TIN2004-07860 (MEDUSA) and by the Comunidad de Madrid under project P-TIC-0223-0505 (PROMULTIDIS).

A plethora of algorithms have been defined for foreground segmentation, a fundamental stage for many computer vision applications. In this work, we propose a post-processing framework to improve foreground segmentation performance of background subtraction algorithms. We define a hierarchical framework for extending segmented foreground pixels to undetected foreground object areas and for removing erroneously segmented foreground. Firstly, we create a motion-aware hierarchical image segmentation of each frame that prevents merging foreground and background image regions. Then, we estimate the quality of the foreground mask through the fitness of the binary regions in the mask and the hierarchy of segmented regions. Finally, the improved foreground mask is obtained as an optimal labeling by jointly exploiting foreground quality and spatial color relations in a pixel-wise fully-connected Conditional Random Field. Experiments are conducted over four large and heterogeneous datasets with varied challenges (CDNET2014, LASIESTA, SABS and BMC) demonstrating the capability of the proposed framework to improve background subtraction results ; This work was partially supported by the Spanish Government (HAVideo, TEC2014-53176-R)

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 2012 ; We 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.

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. Cavallaro, and J. M. Martínez, "Standalone evaluation of deterministic video tracking", in 19th IEEE International Conference on Image Processing (ICIP), 2012. Orlando, pp. 1353 - 1356 ; We present an approach for performance evaluation of deterministic video trackers without ground-truth data. The proposed approach detects if a tracker is correctly operating over time using two main steps. First, it transforms the output of the localization step into a distribution of the target state, which emulates a multi-hypothesis tracker. Then, the uncertainty of such distribution is estimated to determine the time instants when the tracker is stable. A time-reversed analysis is used to identify tracker recovery after unsuccessful operation. The proposed approach is demonstrated on the well-known MeanShift tracker. The results over a heterogeneous dataset show that the proposed approach outperforms the related state-of-the-art methods in presence of tracking challenges such as occlusions, illumination and scale changes, and clutter. ; Work partially supported by the Spanish Government (TEC2011-25995 EventVideo), by the Consejería de Educación of the Comunidad de Madrid, and by The European Social Fund.

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. Cavallaro, and J. M. Martínez, "Evaluation of on-line quality estimators for object tracking", in 17th IEEE International Conference on Image Processing, ICIP 2010, p. 825-828 ; Failure of tracking algorithms is inevitable in real and on-line tracking systems. The online estimation of the track quality is therefore desirable for detecting tracking failures while the algorithm is operating. In this paper, we propose a taxonomy and present a comparative evaluation of online quality estimators for video object tracking. The measures are compared over a heterogeneous video dataset with standard sequences. Among other results, the experiments show, that the Observation Likelihood (OL) measure is an appropriate quality measure for overall tracking performance evaluation, while the Template Inverse Matching (TIM) measure is appropriate to detect the start and the end instants of tracking failures. ; Work 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. Part of the work reported in this paper was done during a research stay of the first author under a research grant (funded by UAM) at Queen Mary University of London (UK).

Applying people detectors to unseen data is challenging since patterns distributions, such as viewpoints, motion, poses, backgrounds, occlusions and people sizes, may significantly differ from the ones of the training dataset. In this paper, we propose a coarse-to-fine framework to adapt frame by frame people detectors during runtime classification, without requiring any additional manually labeled ground truth apart from the offline training of the detection model. Such adaptation make use of multiple detectors mutual information, i.e., similarities and dissimilarities of detectors estimated and agreed by pair-wise correlating their outputs. Globally, the proposed adaptation discriminates between relevant instants in a video sequence, i.e., identifies the representative frames for an adaptation of the system. Locally, the proposed adaptation identifies the best configuration (i.e., detection threshold) of each detector under analysis, maximizing the mutual information to obtain the detection threshold of each detector. The proposed coarse-to-fine approach does not require training the detectors for each new scenario and uses standard people detector outputs, i.e., bounding boxes. The experimental results demonstrate that the proposed approach outperforms state-of-the-art detectors whose optimal threshold configurations are previously determined and fixed from offline training data ; This work has been partially supported by the Spanish government under the project TEC2014-53176-R (HAVideo)

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. D. Ortego, J. C. SanMiguel and J. M. Martínez, "Long-Term Stationary Object Detection Based on Spatio-Temporal Change Detection," in IEEE Signal Processing Letters, vol. 22, no. 12, pp. 2368-2372, Dec. 2015. doi:10.1109/LSP.2015.2482598 ; We present a block-wise approach to detect stationary objects based on spatio-Temporal change detection. First, block candidates are extracted by filtering out consecutive blocks containing moving objects. Then, an online clustering approach groups similar blocks at each spatial location over time via statistical variation of pixel ratios. The stability changes are identified by analyzing the relationships between the most repeated clusters at regular sampling instants. Finally, stationary objects are detected as those stability changes that exceed an alarm time and have not been visualized before. Unlike previous approaches making use of Background Subtraction, the proposed approach does not require foreground segmentation and provides robustness to illumination changes, crowds and intermittent object motion. The experiments over an heterogeneous dataset demonstrate the ability of the proposed approach for short-and long-Term operation while overcoming challenging issues. ; This work was partially supported by the Spanish Government (HA-Video TEC2014-5317-R) and by the TEC department (UAM).