Multiple Object Tracking from appearance by hierarchically clustering tracklets

Current approaches in Multiple Object Tracking (MOT) rely on the spatio-temporal coherence between detections combined with object appearance to match objects from consecutive frames. In this work, we explore MOT using object appearances as the main source of association between objects in a video, using spatial and temporal priors as weighting factors. We form initial tracklets by leveraging on the idea that instances of an object that are close in time should be similar in appearance, and build the final object tracks by fusing the tracklets in a hierarchical fashion. We conduct extensive experiments that show the effectiveness of our method over three different MOT benchmarks, MOT17, MOT20, and DanceTrack, being competitive in MOT17 and MOT20 and establishing state-of-the-art results in DanceTrack.Comment: To be published in BMVC 202

Improving Spatial Codification in Semantic Segmentation

This paper explores novel approaches for improving the spatial codification for the pooling of local descriptors to solve the semantic segmentation problem. We propose to partition the image into three regions for each object to be described: Figure, Border and Ground. This partition aims at minimizing the influence of the image context on the object description and vice versa by introducing an intermediate zone around the object contour. Furthermore, we also propose a richer visual descriptor of the object by applying a Spatial Pyramid over the Figure region. Two novel Spatial Pyramid configurations are explored: Cartesian-based and crown-based Spatial Pyramids. We test these approaches with state-of-the-art techniques and show that they improve the Figure-Ground based pooling in the Pascal VOC 2011 and 2012 semantic segmentation challenges.Comment: Paper accepted at the IEEE International Conference on Image Processing, ICIP 2015. Quebec City, 27-30 September. Project page: https://imatge.upc.edu/web/publications/improving-spatial-codification-semantic-segmentatio

Detection and segmentation of faces using binary partition trees

In this paper we improve the face detection and segmentation technique proposed in [1]. In order to obtain the shape of the face, we use a region based approach and find the face as a set of regions from a generic segmentation. The original image is segmented and a partition tree is created by merging regions from this partition. Facial descriptors and a similarity measure to faces are computed for each node. The analysis is performed using information from the regions represented by the node and also information from neighboring regions. The new method overcomes the rigidity of the tree structure and allows the extraction of new facial regions that are not represented as nodes in the tree. A search algorithm selects the nodes associated to faces. The use of information from neighboring regions significantly improves the performance of the algorithm and avoids the postprocessing step used in our previous work to completely extract the facial regions.Eje: Programación de imágenesRed de Universidades con Carreras en Informática (RedUNCI

GOS: búsqueda visual de imágenes

No es fácil encontrar aquello que buscamos. Los sistemas de búsqueda automatizados son máquinas que deben interpretar la información introducida por el usuario para ejecutar una petición y recuperar la información deseada. La tarea del “traductor” es esencial en el proceso, por tanto, una buena interfaz de usuario (GUI) es determinante en el éxito de la búsqueda. Os presentamos el GOS (Graphic Object Searcher), una aplicación que utiliza un sistema de búsqueda visual, para recuperar imágenes similares a otra imagen usada como ejemplo en la consulta. La industria del sector audiovisual está especialmente interesada en el desarrollo de este tipo de herramientas de gestión de contenidos que han de facilitar su trabajo diario.Peer Reviewe

MPEG-4 : una nueva representación de la información audio-visual

Peer Reviewe

Split ring resonator-based left-handed coplanar waveguide

In this letter, a planar left-handed propagating medium consisting of a coplanar waveguide (CPW) inductively coupled to split ring resonators (SRR) and periodically loaded with narrow metallic wires is proposed. The wires make the structure behave as a microwave plasma with a negative effective permittivity which covers a broad frequency range. The negative permeability required to achieve left-handed wave propagation is provided by the rings in the vicinity of their resonant frequency. The result is a structure which allows negative wave propagation in a narrow frequency band. The transmission coefficient measured in a fabricated prototype device exhibits very low insertion losses in the pass band and high-frequency selectivity. Since rings are much smaller than signal wavelength at resonance and can be easily tuned, SRR-CPW-based structures are of interest for the design of very compact microwave circuits based on left handedness

Design of wide-band semi-lumped bandpass filters using open split ring resonators

Open split ring resonators (OSRRs) are used in this letter to design wide-band semi-lumped bandpass filters. OSRRs work as lumped LC series elements due to their small electrical size and can be then used as building blocks of reduced size band pass filters. The values of the capacitance, C, and inductance, L, of the OSRR are controlled by adjusting the geometrical parameters of the coupled open rings. In our design, the OSRRs are connected through quarter-wave lines which act as inverters. The impedance of these inverters have been conveniently calculated to achieve the filter specifications. Finally bending and/or meandering techniques have been applied so as to obtain highly compact designs. Experimental verification is provided and good agreement has been found between electromagnetic simulations and measurements.Ministerio de Educación y Ciencia TEC2004-04249-C02-01, TEC2004-04249-C02-02, TEC2004-0321

Accurate circuit analysis of resonant-type left handed transmission lines with inter-resonator coupling

In this paper, a circuit model for the description of left handed transmission lines based on complementary split rings resonators CSRRs is proposed. As compared to previous models, coupling between adjacent resonators is included in the present work. The conditions that make this coupling significant are discussed. Specifically, it will be shown that it is barely present when circular CSRRs are used to implement the left handed transmission line. However, if the line is loaded with rectangular CSRRs separated by a small distance, inter-resonator coupling is important and it significantly influences the electromagnetic behavior of the structures. It will be also shown that under low or moderate coupling, it is possible to describe the structures by means of a simplified model with modified parameters. Several prototype devices with different CSRR topologies and coupling levels have been fabricated to illustrate the phenomenology associated with these structures and the accuracy of their model descriptions. The results of this work can be of interest for the design of planar microwave circuits based on CSRR left handed lines.Ministerio de Economía y Ciencias de España-TEC2004-04249-C02-01 y TEC2004-04249-C02-02Comisión Europea (Red de Excelencia)-E 500252-2 METAMORPHOS

Bags of local convolutional features for scalable instance search

This work proposes a simple instance retrieval pipeline based on encoding the convolutional features of CNN using the bag of words aggregation scheme (BoW). Assigning each local array of activations in a convolutional layer to a visual word produces an assignment map, a compact representation that relates regions of an image with a visual word. We use the assignment map for fast spatial reranking, obtain- ing object localizations that are used for query expansion. We demonstrate the suitability of the BoW representation based on local CNN features for instance retrieval, achieving competitive performance on the Oxford and Paris buildings benchmarks. We show that our proposed system for CNN feature aggregation with BoW outperforms state-of-the-art techniques using sum pooling at a subset of the challenging TRECVid INS benchmark

Planar magnetoinductive wave transducers : theory and applications

Transduction of magnetoinductive waves (MIWs) in planar technology is demonstrated. A transducer consisting of a one-dimensional periodic array of metallic split squared ring resonators (SSRR), placed between a pair of microstrip lines on a planar substrate has been fabricated and measured. The microstrip lines are inductively coupled to the SSRRs located at the ends of the periodic array and excite MIWs that propagate along the array. The theoretical model for the dispersion of MIWs is used to predict the dispersion relation and the delay time in the device. The delay time was measured and a good agreement was found with the theoretical predictions. The transmission coefficient of the device was also measured. The theoretical and experimental results suggest that the proposed configuration can find application in the design of delay lines and other microwave devices. In fact, the behavior of the proposed transducer is similar to that of the conventional ferritemagnetostatic-wavetransducer. However, ferrite devices are fragile, difficult to integrate, and require a heavy external magnet or electromagnet to magnetize the ferrite to saturation. Since all these drawbacks are not present in the proposed configuration, it may be a useful alternative to those devices for many practical applications