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  • 1651.
    Verikas, Antanas
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Intelligenta system (IS-lab). Kaunas University of Technology, Kaunas, Lithuania.
    Gelzinis, Adas
    Kaunas University of Technology, Kaunas, Lithuania.
    Bacauskiene, Marija
    Kaunas University of Technology, Kaunas, Lithuania .
    Olenina, Irina
    Klaipeda University, Klaipeda, Lithuania.
    Olenin, Sergej
    Klaipeda University, Klaipeda, Lithuania .
    Vaiciukynas, Evaldas
    Kaunas University of Technology, Kaunas, Lithuania.
    Phase congruency-based detection of circular objects applied to analysis of phytoplankton images2012Ingår i: Pattern Recognition, ISSN 0031-3203, E-ISSN 1873-5142, Vol. 45, nr 4, s. 1659-1670Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Detection and recognition of objects representing the Prorocentrum minimum (P. minimum) species in phytoplankton images is the main objective of the article. The species is known to cause harmful blooms in many estuarine and coastal environments. A new technique, combining phase congruency-based detection of circular objects in images, stochastic optimization-based object contour determination, and SVM- as well as random forest (RF)-based classification of objects was developed to solve the task. A set of various features including a subset of new features computed from phase congruency preprocessed images was used to characterize extracted objects. The developed algorithms were tested using 114 images of 1280×960 pixels. There were 2088 P. minimum cells in the images in total. The algorithms were able to detect 93.25% of objects representing P. minimum cells and correctly classified 94.9% of all detected objects. The feature set used has shown considerable tolerance to out-of-focus distortions. The obtained results are rather encouraging and will be used to develop an automated system for obtaining abundance estimates of the species. © 2011 Elsevier Ltd All rights reserved.

  • 1652.
    Verikas, Antanas
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Gelzinis, Adas
    Kaunas University of Technology, Lithuania.
    Bacauskiene, Marija
    Kaunas University of Technology, Lithuania.
    Uloza, Virgilijus
    Kaunas University of Medicine, Kaunas, Lithuania.
    Intelligent vocal cord image analysis for categorizing laryngeal diseases2005Ingår i: Innovations in applied artificial intelligence / [ed] Moonis Ali, Floriana Esposito, Springer, 2005, s. 69-78Konferensbidrag (Refereegranskat)
    Abstract [en]

    Colour, shape, geometry, contrast, irregularity and roughness of the visual appearance of vocal cords are the main visual features used by a physician to diagnose laryngeal diseases. This type of examination is rather subjective and to a great extent depends on physician’s experience. A decision support system for automated analysis of vocal cord images, created exploiting numerous vocal cord images can be a valuable tool enabling increased reliability of the analysis, and decreased intra- and inter-observer variability. This paper is concerned with such a system for analysis of vocal cord images. Colour, texture, and geometrical features are used to extract relevant information. A committee of artificial neural networks is then employed for performing the categorization of vocal cord images into healthy, diffuse, and nodular classes. A correct classification rate of over 93% was obtained when testing the system on 785 vocal cord images.

  • 1653.
    Verikas, Antanas
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Gelzinis, Adas
    Kaunas University of Technology, Kaunas, Lithuania.
    Malmqvist, Kerstin
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Using Labelled and Unlabelled Data to Train a Multilayer Perceptron for Colour Classification in Graphic Arts1999Ingår i: Multiple approaches to intelligent systems: 12th International Conference on Industrial and Engineering Applications of Artificial Intelligence and Expert Systems IEA/AIE-99, Cairo, Egypt, May 31 - June 3, 1999. Proceedings / [ed] Ibrahim Imam, Yves Kodratoff, Ayman El-Dessouki and Moonis Ali, Berlin: Springer Berlin/Heidelberg, 1999, s. 550-559Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents an approach to using both labelled and unlabelled data to train a multi-layer perceptron. The unlabelled data are iteratively pre-processed by a perceptron being trained to obtain the soft class label estimates. It is demonstrated that substantial gains in classification performance may be achieved from the use of the approach when the labelled data do not adequately represent the entire class distributions. The experimental investigations performed have shown that the approach proposed may be successfully used to train networks for colour classification in graphic arts.

  • 1654.
    Verikas, Antanas
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Intelligenta system (IS-lab).
    Uloza, Virgilijus
    Department of Otolaryngology, Kaunas University of Medicine, Kaunas 50009, Lithuania.
    Bacauskiene, Marija
    Department of Applied Electronics, Kaunas University of Technology, Studentu 50, Kaunas 51368, Lithuania.
    Gelzinis, Adas
    Department of Applied Electronics, Kaunas University of Technology, Studentu 50, Kaunas 51368, Lithuania.
    Kelertas, Edgaras
    Department of Applied Electronics, Kaunas University of Technology, Studentu 50, Kaunas 51368, Lithuania.
    Advances in laryngeal imaging2009Ingår i: European Archives of Oto-Rhino-Laryngology, ISSN 0937-4477, E-ISSN 1434-4726, Vol. 266, nr 10, s. 1509-1520Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Imaging and image analysis became an important issue in laryngeal diagnostics. Various techniques, such as videostroboscopy, videokymography, digital kymograpgy, or ultrasonography are available and are used in research and clinical practice. This paper reviews recent advances in imaging for laryngeal diagnostics.

  • 1655.
    Vernon, David
    Högskolan i Skövde, Forskningscentrum för Informationsteknologi. Högskolan i Skövde, Institutionen för kommunikation och information.
    Goal-directed Action and Eligible Forms of Embodiment2013Ingår i: Constructivist Foundations, ISSN 1782-348X, E-ISSN 1782-348X, Vol. 9, nr 1, s. 85-86Artikel, forskningsöversikt (Refereegranskat)
  • 1656.
    Vernon, David
    Högskolan i Skövde, Forskningscentrum för Informationsteknologi. Högskolan i Skövde, Institutionen för kommunikation och information.
    Interpreting Ashby - But which One?2013Ingår i: Constructivist Foundations, ISSN 1782-348X, E-ISSN 1782-348X, Vol. 9, nr 1, s. 111-113Artikel, forskningsöversikt (Refereegranskat)
  • 1657.
    Vernon, David
    Högskolan i Skövde, Institutionen för informationsteknologi. Högskolan i Skövde, Forskningscentrum för Informationsteknologi.
    Reconciling Constitutive and Behavioural Autonomy: The Challenge of Modelling Development in Enactive Cognition2016Ingår i: Intellectica, ISSN 0769-4113, Vol. 65, s. 63-79Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the enactive paradigm of cognitive science, development plays a crucial role in the realization of cognition. This position runs counter to the computational functionalism upon which cognitivist and classical artificial intelligence systems are founded, especially the assumption that cognition can be achieved by embedding pre-formed knowledge. The enactive stance involves a progressive phased transition from cognitive capacity to cognitive capability, highlighting the role of development in extending the timescale of a cognitive agent’s prospective abilities and in expanding its repertoire of effective action. We review briefly some necessary conditions for cognitive development, drawing on examples from developmental psychology, illustrating the ideas by looking at the ontogenesis of instru- mental helping and collaboration in infants, and identifying some of the essential elements of a developmental cognitive architecture. We then focus on the fact that enactive sys- tems are operationally-closed, autonomous, and self-maintaining. Consequently, there are organizational constitutive processes at play as well as behavioural ones. Reconciling these complementary processes poses a significant challenge for the creation of complete model of development that must show how constitutive autonomy is compatible with and may even give rise to behavioural autonomy. We conclude by drawing attention to recent research which could provide a way of addressing this challenge. 

  • 1658.
    Vesterlund, Folke
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    GPU Based Blob Detection: Implementation and Evaluation of a Blob Detection Algorithm for Tracking in Agility Training2019Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
  • 1659.
    Vi, Margareta
    Linköpings universitet, Institutionen för systemteknik, Datorseende.
    Object Detection Using Convolutional Neural Network Trained on Synthetic Images2018Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Training data is the bottleneck for training Convolutional Neural Networks. A larger dataset gives better accuracy though also needs longer training time. It is shown by finetuning neural networks on synthetic rendered images, that the mean average precision increases. This method was applied to two different datasets with five distinctive objects in each. The first dataset consisted of random objects with different geometric shapes. The second dataset contained objects used to assemble IKEA furniture. The neural network with the best performance, trained on 5400 images, achieved a mean average precision of 0.81 on a test which was a sample of a video sequence. Analysis of the impact of the factors dataset size, batch size, and numbers of epochs used in training and different network architectures were done. Using synthetic images to train CNN’s is a promising path to take for object detection where access to large amount of annotated image data is hard to come by.

  • 1660.
    Vidal-Calleja, Teresa
    et al.
    University of Sydney, Australia.
    Berger, Cyrille
    Linköpings universitet, Institutionen för datavetenskap, KPLAB - Laboratoriet för kunskapsbearbetning. Linköpings universitet, Tekniska högskolan.
    Lacroix, Simon
    Robotics and InterationS group, LAAS, France.
    Event-driven loop closure in multi-robot mapping2009Ingår i: Proceedings of the IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), IEEE conference proceedings, 2009, s. 1535-1540Konferensbidrag (Refereegranskat)
    Abstract [en]

    A large-scale mapping approach is combined with multiple robots events to achieve cooperative mapping. The mapping approach used is based on hierarchical SLAM -global level and local maps-, which is generalized for the multi-robot case. In particular, the consequences of multi-robot loop closing events (common landmarks detection and relative pose measurement between robots) are analyzed and managed at a global level. We present simulation results for each of these events using aerial and ground robots, and experimental results obtained with ground robots.

  • 1661.
    Vidal-Calleja, Teresa
    et al.
    LAAS/CNRS, University of Toulouse, Toulouse, France.
    Berger, Cyrille
    LAAS/CNRS, University of Toulouse, Toulouse, France.
    Solà, Joan
    LAAS/CNRS, University of Toulouse, Toulouse, France.
    Lacroix, Simon
    LAAS/CNRS, University of Toulouse, Toulouse, France.
    Environment Modeling for Cooperative Aerial/Ground Robotic Systems2009Ingår i: Proceedings of the 14th International Symposium on Robotics Research (ISRR), Springer, 2009, s. 681-696Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper addresses the cooperative localization and visual mapping problem for multiple aerial and ground robots.We propose the use of heterogeneous visual landmarks, points and line segments. A large-scale SLAM algorithm is generalized to manage multiple robots, in which a global graph maintains the topological relationships between a series of local sub-maps built by the different robots. Only single camera setups are considered: in order to achieve undelayed initialization, we present a novel parametrization for lines based on anchored Plücker coordinates, to which we add extensible endpoints to enhance their representativeness. The built maps combine such lines with 3D points parametrized in inverse-depth. The overall approach is evaluated with real-data taken with a helicopter and a ground rover in an abandoned village.

  • 1662.
    Vidal-Calleja, Teresa
    et al.
    Australian Centre for Field Robotics, University of Sydney, NSW, Australia.
    Berger, Cyrille
    CNRS; LAAS; Toulouse, France and Université de Toulouse; UPS, INSA, INP, ISAE; LAAS; Toulouse, France.
    Solà, Joan
    CNRS; LAAS; Toulouse, France and Université de Toulouse; UPS, INSA, INP, ISAE; LAAS; Toulouse, France.
    Lacroix, Simon
    CNRS; LAAS; Toulouse, France and Université de Toulouse; UPS, INSA, INP, ISAE; LAAS; Toulouse, France.
    Large scale multiple robot visual mapping with heterogeneous landmarks in semi-structured terrain2011Ingår i: Robotics and Autonomous Systems, ISSN 0921-8890, E-ISSN 1872-793X, Vol. 59, nr 9, s. 654-674Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper addresses the cooperative localization and visual mapping problem with multiple heterogeneous robots. The approach is designed to deal with the challenging large semi-structured outdoors environments in which aerial/ground ensembles are to evolve. We propose the use of heterogeneous visual landmarks, points and line segments, to achieve effective cooperation in such environments. A large-scale SLAM algorithm is generalized to handle multiple robots, in which a global graph maintains the relative relationships between a series of local sub-maps built by the different robots. The key issue when dealing with multiple robots is to find the link between them, and to integrate these relations to maintain the overall geometric consistency; the events that introduce these links on the global graph are described in detail. Monocular cameras are considered as the primary extereoceptive sensor. In order to achieve the undelayed initialization required by the bearing-only observations, the well-known inverse-depth parametrization is adopted to estimate 3D points. Similarly, to estimate 3D line segments, we present a novel parametrization based on anchored Plücker coordinates, to which extensible endpoints are added. Extensive simulations show the proposed developments, and the overall approach is illustrated using real-data taken with a helicopter and a ground rover.

  • 1663.
    Vidholm, Erik
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    A tool for filtering and visualization of digital images in the Fourier domain2003Rapport (Övrigt vetenskapligt)
    Abstract [en]

    A software application for image filtering in the 2D and 3D

  • 1664.
    Vidholm, Erik
    Uppsala universitet.
    Haptic interaction with deformable simplex meshes for 3D segmentation2007Ingår i: Swedish symposium on image analysis (SSBA), 2007, s. 1-4Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    We present a tool for interactive 3D segmentation using deformable

    surfaces represented by simplex meshes. The interaction is performed directly in 3D with a haptic device. Haptic feedback is generated from image data in order to provide the user with information that can facilitate tuning of model parameters. It is also possible to directly interact with the mesh by grabbing vertices and move them in order to initialize the model properly or guide it during deformation.

  • 1665.
    Vidholm, Erik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Agmund, Jonas
    Fakultetsövergripande enheter, Centrum för bildanalys. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Fast surface rendering for interactive medical image segmentation with haptic feedback2004Ingår i: Proceedings of SIGRAD 2004: Special theme - Environmental visualization, 2004Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this work, we present a haptic-enabled application

    for interactive editing in medical

    image segmentation. We use a fast surface rendering algorithm to

    display the different segmented objects, and we apply a

    proxy-based volume haptics algorithm to be able to touch and edit these

    objects at interactive rates. As an application example,

    we show how the system can be used to initialize a fast marching

    segmentation algorithm for extracting the liver in magnetic resonance (MR)

    images and then edit the result if it is incorrect.

  • 1666.
    Vidholm, Erik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Golubovic, Milan
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för radiologi, onkologi och strålningsvetenskap, Enheten för radiologi.
    Nilsson, Sven
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för radiologi, onkologi och strålningsvetenskap, Enheten för radiologi.
    Nyström, Ingela
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys.
    Accurate and reproducible semi-automatic liver segmentation using haptic interaction2008Ingår i: Medical Imaging 2008: Visualization, Image-Guided Procedures, and Modeling, Bellingham, WA, 2008, s. 69182Q:1-8Konferensbidrag (Refereegranskat)
  • 1667.
    Vidholm, Erik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Malmberg, Filip
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys.
    Nyström, Ingela
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys.
    Läkarens känsel hjälper datorn2009Ingår i: Forskning & Framsteg, ISSN 0015-7937, nr 1, s. 62-Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 1668.
    Vidholm, Erik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Sundqvist, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för teknisk databehandling.
    Nyström, Ingela
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Accelerating the Computation of 3D Gradient Vector Flow Fields2006Ingår i: Proc, IEEE , 2006, s. 677-680Konferensbidrag (Refereegranskat)
  • 1669.
    Vidholm, Erik
    et al.
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Tizon, Xavier
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Nyström, Ingela
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Bengtsson, Ewert
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Haptic guided seeding of MRA images for semi-automatic segmentation2004Ingår i: Proceedings of IEEE international symposium on biomedical imaging: From nano to macro, 2004, s. 288-291Konferensbidrag (Refereegranskat)
    Abstract [en]

    We investigate how stereo graphics

    and haptics can be combined to facilitate the seeding procedure

    in semi-automatic segmentation of magnetic resonance angiography (MRA)

    images. Real-time volume rendering using maximum intensity

    projections (MIPs) has been implemented together with a haptic

    rendering method that provides force feedback based on local

    gradients and intensity values. This combination allows a

    user to trace vessels in the image, and to

    place seed-points directly in the 3D data set. Seed-regions

    are propagated from the seed-points

    according to an algorithm that favors bright voxels.

    An experienced user have tested the interface

    on whole-body MRA images with promising results.

  • 1670.
    Viksten, Fredrik
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska högskolan.
    Local Features for Range and Vision-Based Robotic Automation2010Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Robotic automation has been a part of state-of-the-art manufacturing for many decades. Robotic manipulators are used for such tasks as welding, painting, pick and place tasks etc. Robotic manipulators are quite flexible and adaptable to new tasks, but a typical robot-based production cell requires extensive specification of the robot motion and construction of tools and fixtures for material handling. This incurs a large effort both in time and monetary expenses. The task of a vision system in this setting is to simplify the control and guidance of the robot and to reduce the need for supporting material handling machinery.

    This dissertation examines performance and properties of the current state-of-the-art local features within the setting of object pose estimation. This is done through an extensive set of experiments replicating various potential problems to which a vision system in a robotic cell could be subjected. The dissertation presents new local features which are shown to increase the performance of object pose estimation. A new local descriptor details how to use log-polar sampled image patches for truly rotational invariant matching. This representation is also extended to use a scale-space interest point detector which in turn makes it very competitive in our experiments. A number of variations of already available descriptors are constructed resulting in new and competitive features, among them a scale-space based Patch-duplet.

    In this dissertation a successful vision-based object pose estimation system is extended for multi-cue integration, yielding increased robustness and accuracy. Robustness is increased through algorithmic multi-cue integration, combining the individual strengths of multiple local features. Increased accuracy is achieved by utilizing manipulator movement and applying temporal multi-cue integration. This is implemented using a real flexible robotic manipulator arm.

    Besides work done on local features for ordinary image data a number of local features for range data has also been developed. This dissertation describes the theory behind and the application of the scene tensor to the problem of object pose estimation. The scene tensor is a fourth order tensor representation using projective geometry. It is shown how to use the scene tensor as a detector as well as how to apply it to the task of object pose estimation. The object pose estimation system is extended to work with 3D data.

    A novel way of handling sampling of range data when constructing a detector is discussed. A volume rasterization method is presented and the classic Harris detector is adapted to it. Finally, a novel region detector, called Maximally Robust Range Regions, is presented. All developed detectors are compared in a detector repeatability test.

  • 1671.
    Viksten, Fredrik
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska högskolan.
    Object Pose Estimation using Variants of Patch-Duplet and SIFT Descriptors2010Rapport (Övrigt vetenskapligt)
    Abstract [en]

    Recent years have seen a lot of work on local descriptors. In all published comparisons or evaluations, the now quite well-known SIFT-descriptor has been one of the top performers. For the application of object pose estimation, one comparison showed a local descriptor, called the Patch-duplet, of equal or better performance than SIFT. This paper examines different properties of those two descriptors by constructing and evaluating hybrids of them. We also extend upon the object pose estimation experiments of the original Patch-duplet paper. All tests use real images. We also show what impact camera calibration and image rectification has on an application such as object pose estimation. A new feature based on the Patch-duplet descriptor and the DoG detector emerges as the feature of choice under illuminiation changes in a real world application.

  • 1672.
    Viksten, Fredrik
    et al.
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska högskolan.
    Forssén, Per-Erik
    Linköpings universitet, Institutionen för systemteknik, Bildbehandling. Linköpings universitet, Tekniska högskolan.
    Maximally Robust Range Regions2010Rapport (Övrigt vetenskapligt)
    Abstract [en]

    In this work we present a region detector, an adaptation to range data of the popular Maximally Stable Extremal Regions (MSER) region detector. We call this new detector Maximally Robust Range Regions (MRRR). We apply the new detector to real range data captured by a commercially available laser range camera. Using this data we evaluate the repeatability of the new detector and compare it to some other recently published detectors. The presented detector shows a repeatability which is better or the same as the best of the other detectors. The MRRR detector also offers additional data on the detected regions. The additional data could be crucial in applications such as registration or recognition.

  • 1673.
    Viksten, Fredrik
    et al.
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska högskolan.
    Forssén, Per-Erik
    Linköpings universitet, Institutionen för systemteknik, Bildbehandling. Linköpings universitet, Tekniska högskolan.
    Johansson, Björn
    Linköpings universitet, Institutionen för systemteknik, Bildbehandling. Linköpings universitet, Tekniska högskolan.
    Moe, Anders
    Linköpings universitet, Institutionen för systemteknik. Linköpings universitet, Tekniska högskolan.
    Local Image Descriptors for Full 6 Degree-of-Freedom Object Pose Estimation and Recognition2010Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Recent years have seen advances in the estimation of full 6 degree-of-freedom object pose from a single 2D image. These advances have often been presented as a result of, or together with, a new local image feature type. This paper examines how the pose accuracy and recognition robustness for such a system varies with choice of feature type. This is done by evaluating a full 6 degree-of-freedom pose estimation system for 17 different combinations of local descriptors and detectors. The evaluation is done on data sets with photos of challenging 3D objects with simple and complex backgrounds and varying illumination conditions. We examine the performance of the system under varying levels of object occlusion and we find that many features allow considerable object occlusion. From the experiments we can conclude that duplet features, that use pairs of interest points, improve pose estimation accuracy, compared to single point features. Interestingly, we can also show that many features previously used for recognition and wide-baseline stereo are unsuitable for pose estimation, one notable example are the affine covariant features that have been proven quite successful in other applications. The data sets and their ground truths are available on the web to allow future comparison with novel algorithms.

  • 1674.
    Viksten, Fredrik
    et al.
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska högskolan.
    Moe, Anders
    Linköpings universitet, Institutionen för systemteknik, Bildbehandling. Linköpings universitet, Tekniska högskolan.
    A Local Single-Patch Feature for Pose Estimation Using the Log-Polar Transform: Revised VersionManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    This paper presents a local image feature, based on the log-polartransform which together with the Fourier transform enables feature matching invariant to orientation and scalechanges. It is shown that this feature can be used for poseestimation of 3D objects with unknown pose, with clutteredbackground and with occlusion. The proposed method is compared to apreviously published one and the new feature is found to be about asgood or better as the old one for this task.

  • 1675.
    Viksten, Fredrik
    et al.
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska högskolan.
    Nordberg, Klas
    Linköpings universitet, Institutionen för systemteknik, Bildbehandling. Linköpings universitet, Tekniska högskolan.
    A Local Geometry-Based Descriptor for 3D Data Applied to Object Pose Estimation2010Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    A local descriptor for 3D data, the scene tensor, is presentedtogether with novel applications.  It can describe multiple planarsegments in a local 3D region; for the case of up to three segments itis possible to recover the geometry of the local region in terms of thesize, position and orientation of each of the segments from thedescriptor. In the setting of range data, this property makes thedescriptor unique compared to other popular local descriptors, such asspin images or point signatures.  The estimation of the descriptor canbe based on 3D orientation tensors that, for example, can be computeddirectly from surface normals but the representation itself does notdepend on a specific estimation method and can also be applied to othertypes of 3D data, such as motion stereo. A series of experiments onboth real and synthetic range data show that the proposedrepresentation can be used as a interest point detector with highrepeatability. Further, the experiments show that, at such detectedpoints, the local geometric structure can be robustly recovered, evenin the presence of noise. Last we expand a framework for object poseestimation, based on the scene tensor and previously appliedsuccessfully on 2D image data, to work also on range data. Poseestimation from real range data shows that there are advantages oversimilar descriptors in 2D and that use of range data gives superiorperformance.

  • 1676.
    Viksten, Fredrik
    et al.
    Linköpings universitet, Institutionen för systemteknik, Bildkodning. Linköpings universitet, Tekniska högskolan.
    Nordberg, Klas
    Linköpings universitet, Institutionen för systemteknik, Bildbehandling. Linköpings universitet, Tekniska högskolan.
    Kalms, Mikael
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska högskolan.
    Point-of-Interest Detection for Range Data2008Ingår i: International Conference on Pattern Recognition (ICPR), IEEE , 2008, s. 1-4Konferensbidrag (Refereegranskat)
    Abstract [en]

    Point-of-interest detection is a way of reducing the amount of data that needs to be processed in a certain application and is widely used in 2D image analysis. In 2D image analysis, point-of-interest detection is usually related to extraction of local descriptors for object recognition, classification, registration or pose estimation. In analysis of range data however, some local descriptors have been published in the last decade or so, but most of them do not mention any kind of point-of-interest detection. We here show how to use an extended Harris detector on range data and discuss variants of the Harris measure. All described variants of the Harris detector for 3D should also be usable in medical image analysis, but we focus on the range data case. We do present a performance evaluation of the described variants of the Harris detector on range data.

  • 1677.
    Viksten, Fredrik
    et al.
    Linköpings universitet, Institutionen för systemteknik, Bildbehandling. Linköpings universitet, Tekniska högskolan.
    Söderberg, Robert
    Linköpings universitet, Institutionen för systemteknik, Bildbehandling. Linköpings universitet, Tekniska högskolan.
    Nordberg, Klas
    Linköpings universitet, Institutionen för systemteknik, Bildbehandling. Linköpings universitet, Tekniska högskolan.
    Perwass, Christian
    Increasing Pose Estimation Performance using Multi-cue Integration2006Ingår i: IEEE International Conference on Robotic and Automation (ICRA), IEEE , 2006, s. 3760-3767Konferensbidrag (Refereegranskat)
    Abstract [en]

    We have developed a system which integrates the information output from several pose estimation algorithms and from several views of the scene. It is tested in a real setup with a robotic manipulator. It is shown that integrating pose estimates from several algorithms increases the overall performance of the pose estimation accuracy as well as the robustness as compared to using only a single algorithm. It is shown that increased robustness can be achieved by using pose estimation algorithms based on complementary features, so called algorithmic multi-cue integration (AMC). Furthermore it is also shown that increased accuracy can be achieved by integrating pose estimation results from different views of the scene, so-called temporal multi-cue integration (TMC). Temporal multi-cue integration is the most interesting aspect of this paper.

  • 1678.
    Vina, Francisco
    et al.
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP.
    Smith, Christian
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP. KTH, Skolan för datavetenskap och kommunikation (CSC), Centra, Centrum för Autonoma System, CAS.
    Kragic, Danica
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP.
    Karayiannidis, Yiannis
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP.
    Adaptive Contact Point Estimation for Autonomous Tool Manipulation2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    Autonomous grasping and manipulation of toolsenables robots to perform a large variety of tasks in unstructuredenvironments such as households. Many commonhousehold tasks involve controlling the motion of the tip of a toolwhile it is in contact with another object. Thus, for these types oftasks the robot requires knowledge of the location of the contactpoint while it is executing the task in order to accomplish themanipulation objective. In this work we propose an integraladaptive control law that uses force/torque measurements toestimate online the location of the contact point between thetool manipulated by the robot and the surface which the tooltouches

  • 1679.
    Virk, Gurvinder S.
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap, Elektronik. KTH Royal Institute Technology, CLAWAR, United Kingdom; KTH Royal Institute Technology, CLAWAR, Sweden.
    Park, Hong Seong
    Kangwon National University, Gangwon Do, South Korea..
    Yang, Shuping
    Beijing Research Institute of Automation for Machinery Industry, Beijing, China.
    Wang, Jason
    Beijing E-Cube Technologies Co Ltd, Beijing, China..
    ISO modularity for service robots2017Ingår i: Advances in Cooperative Robotics: Proceedings of the 19th International Conference in CLAWAR 2016 / [ed] M. Tokhi and G. S. Virk, Singapore: World Scientific, 2017, s. 663-671Konferensbidrag (Refereegranskat)
    Abstract [en]

    Robot modularity has been an active area of research for several years and many innovative solutions have been developed which have as yet, not made significant impact on the world stage. To assist market developments, ISO robot modularity standardization was started in 2012 and the current paper presents an overview of the work to develop plug-n-play robot module specifications for service robots. Key definitions are presented together with generic modularization issues which have been identified for service robots.

  • 1680.
    Viña Barrientos, Francisco
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP.
    Robotic Manipulation under Uncertainty and Limited Dexterity2016Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Robotic manipulators today are mostly constrained to perform fixed, repetitive tasks. Engineers design the robot’s workcell specifically tailoredto the task, minimizing all possible uncertainties such as the location of tools and parts that the robot manipulates. However, autonomous robots must be capable of manipulating novel objects with unknown physical properties such as their inertial parameters, friction and shape. In this thesis we address the problem of uncertainty connected to kinematic constraints and friction forces in several robotic manipulation tasks. We design adaptive controllers for opening one degree of freedom mechanisms, such as doors and drawers, under the presence of uncertainty in the kinematic parameters of the system. Furthermore, we formulate adaptive estimators for determining the location of the contact point between a tool grasped by the robot and the environment in manipulation tasks where the robot needs to exert forces with the tool on another object, as in the case of screwing or drilling. We also propose a learning framework based on Gaussian Process regression and dual arm manipulation to estimate the static friction properties of objects. The second problem we address in this thesis is related to the mechanical simplicity of most robotic grippers available in the market. Their lower cost and higher robustness compared to more mechanically advanced hands make them attractive for industrial and research robots. However, the simple mechanical design restrictsthem from performing in-hand manipulation, i.e. repositioning of objects in the robot’s hand, by using the fingers to push, slide and roll the object. Researchers have proposed thus to use extrinsic dexterity instead, i.e. to exploit resources and features of the environment, such as gravity or inertial forces,  that can help the robot to perform regrasps. Given that the robot must then interact with the environment, the problem of uncertainty becomes highly relevant. We propose controllers for performing pivoting, i.e. reorienting the grasped object in the robot’s hand, using gravity and controlling the friction exerted by the fingertips by varying the grasping force.

  • 1681.
    Viña Barrientos, Francisco
    et al.
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP.
    Karayiannidis, Yiannis
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP.
    Smith, Christian
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP.
    Kragic, Danica
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP.
    Adaptive Control for Pivoting with Visual and Tactile Feedback2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this work we present an adaptive control approach for pivoting, which is an in-hand manipulation maneuver that consists of rotating a grasped object to a desired orientation relative to the robot’s hand. We perform pivoting by means of gravity, allowing the object to rotate between the fingers of a one degree of freedom gripper and controlling the gripping force to ensure that the object follows a reference trajectory and arrives at the desired angular position. We use a visual pose estimation system to track the pose of the object and force measurements from tactile sensors to control the gripping force. The adaptive controller employs an update law that accommodates for errors in the friction coefficient,which is one of the most common sources of uncertainty in manipulation. Our experiments confirm that the proposed adaptive controller successfully pivots a grasped object in the presence of uncertainty in the object’s friction parameters.

  • 1682.
    Vondrus, M.
    et al.
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Wester, K.
    Busch, C.
    Bengtsson, E.
    Malmström, P.-U.
    A New Approach Towards Microvessel Quantification2001Ingår i: 14th International Congress ofCytology, Amsterdam, The Netherlands, 2001, s. 8 pages-Konferensbidrag (Övrigt vetenskapligt)
  • 1683.
    Wahlberg, Fredrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Interpreting the Script: Image Analysis and Machine Learning for Quantitative Studies of Pre-modern Manuscripts2017Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The humanities have for a long time been a collection of fields that have not gained from the advancements in computational power, as predicted by Moore´s law.  Fields like medicine, biology, physics, chemistry, geology and economics have all developed quantitative tools that take advantage of the exponential increase of processing power over time.  Recent advances in computerized pattern recognition, in combination with a rapid digitization of historical document collections around the world, is about to change this.

    The first part of this dissertation focuses on constructing a full system for finding handwritten words in historical manuscripts. A novel segmentation algorithm is presented, capable of finding and separating text lines in pre-modern manuscripts.  Text recognition is performed by translating the image data of the text lines into sequences of numbers, called features. Commonly used features are analysed and evaluated on manuscript sources from the Uppsala University library Carolina Rediviva and the US Library of Congress.  Decoding the text in the vast number of photographed manuscripts from our libraries makes computational linguistics and social network analysis directly applicable to historical sources. Hence, text recognition is considered a key technology for the future of computerized research methods in the humanities.

    The second part of this thesis addresses digital palaeography, using a computers superior capacity for endlessly performing measurements on ink stroke shapes. Objective criteria of character shapes only partly catches what a palaeographer use for assessing similarity. The palaeographer often gets a feel for the scribe's style.  This is, however, hard to quantify.  A method for identifying the scribal hands of a pre-modern copy of the revelations of saint Bridget of Sweden, using semi-supervised learning, is presented.  Methods for production year estimation are presented and evaluated on a collection with close to 11000 medieval charters.  The production dates are estimated using a Gaussian process, where the uncertainty is inferred together with the most likely production year.

    In summary, this dissertation presents several novel methods related to image analysis and machine learning. In combination with recent advances of the field, they enable efficient computational analysis of very large collections of historical documents.

  • 1684.
    Wahlberg, Fredrik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Brun, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Feature space de-noising for text recognition2014Ingår i: Proceedings of SSBA, 2014, 2014Konferensbidrag (Övrigt vetenskapligt)
  • 1685.
    Wahlberg, Fredrik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Brun, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Feature space denoising improves word spotting2013Ingår i: Proc. 2nd International Workshop on Historical Document Imaging and Processing, New York: ACM Press, 2013, s. 59-66Konferensbidrag (Refereegranskat)
    Abstract [en]

    Some of the sliding window features commonly used in off-line handwritten text recognition are inherently noisy or sen-sitive to image noise. In this paper, we investigate the ef-fects of several de-noising filters applied in the feature spaceand not in the image domain. The purpose is to target theintrinsic noise of these features, stemming from the com-plex shapes of handwritten characters. This noise is presenteven if the image has been captured without any kind ofartefacts or noise. An evaluation, using a public database,is presented showing that the recognition of word-spottingcan be improved considerably by using de-noising filters inthe feature space.

  • 1686.
    Wahlberg, Fredrik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Brun, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Feature Weight Optimization and Pruning in Historical Text Recognition2013Ingår i: Advances of Visual Computing: 9th International Symposium, ISVC 2013, Rethymnon, Crete, Greece, July 29-31, 2013. Proceedings, Part II / [ed] George Bebis, Springer Berlin/Heidelberg, 2013, s. 98-107Konferensbidrag (Refereegranskat)
    Abstract [en]

    In handwritten text recognition, "sliding window" feature extraction represent the visual information contained in written text as feature vector sequences. In this paper, we explore the parameter space of feature weights in search for optimal weights and feature selection using the coordinate descent method. We report a gain of about 5% AUC performance. We use a public dataset for evaluation and also discuss the effects and limitations of "word pruning," a technique in word spotting that is commonly used to boost performance and save computational time.

  • 1687.
    Wahlberg, Fredrik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Brun, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Graph Based Line Segmentation on Cluttered Handwritten Manuscripts2012Ingår i: Proceedings of the 21st International Conference on Pattern Recognition, 2012, IEEE , 2012, s. 1570-1573Konferensbidrag (Refereegranskat)
    Abstract [en]

    We propose a two phase line segmentationmethod for handwritten pre-modern densely writ-ten manuscripts. The proposed method combinesthe robustness of projection based methods withthe flexibility of graph based methods. The resultare cut-outs of the image containing each text line.Overlapping characters, help lines and degradationcan create foreground elements spanning several linesthat are hard to separate. We treat the problem offinding a cut through the text line separation as agraph optimization problem, which allows for flexibleseparation of entangled components.The proposed method has been tested on two me-dieval sources with satisfying results. A comparison tosimilar methods, using standard metrics, is presented.

  • 1688.
    Wahlberg, Fredrik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Brun, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Mårtensson, Lasse
    Writer identification using the Quill-Curvature feature in old manuscripts2015Ingår i: Proceedings of SSBA, 2015, 2015Konferensbidrag (Övrigt vetenskapligt)
  • 1689.
    Wahlberg, Fredrik
    et al.
    Uppsala universitet, Avdelningen för visuell information och interaktion.
    Brun, Anders
    Uppsala universitet, Avdelningen för visuell information och interaktion.
    Mårtensson, Lasse
    Högskolan i Gävle, Akademin för utbildning och ekonomi, Avdelningen för humaniora, Svenska språket och genusvetenskap.
    Writer identification using the Quill-Curvature feature in old manuscripts2015Ingår i: Proceedings of SSBA, 2015, 2015Konferensbidrag (Övrigt vetenskapligt)
  • 1690.
    Wahlberg, Fredrik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Dahllöf, Mats
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Språkvetenskapliga fakulteten, Institutionen för lingvistik och filologi.
    Mårtensson, Lasse
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Språkvetenskapliga fakulteten, Institutionen för nordiska språk.
    Brun, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Word Spotting in Pre-Modern Manuscripts using Dynamic Time Warping2012Ingår i: Proceedings of SSBA, 2012, 2012Konferensbidrag (Övrigt vetenskapligt)
  • 1691.
    Wahlberg, Fredrik
    et al.
    Uppsala universitet, Avdelningen för visuell information och interaktion.
    Dahllöf, Mats
    Uppsala universitet, Institutionen för lingvistik och filologi.
    Mårtensson, Lasse
    Uppsala universitet, Institutionen för nordiska språk.
    Brun, Anders
    Uppsala universitet, Avdelningen för visuell information och interaktion.
    Word Spotting in Pre-Modern Manuscripts using Dynamic Time Warping2012Ingår i: Proceedings of SSBA, 2012, 2012Konferensbidrag (Övrigt vetenskapligt)
  • 1692.
    Wahlberg, Fredrik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion.
    Mårtensson, Lasse
    Brun, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Estimating manuscript production dates using both image and language data2016Ingår i: Proceedings of SSBA, 2016, 2016Konferensbidrag (Övrigt vetenskapligt)
  • 1693.
    Wahlberg, Fredrik
    et al.
    Uppsala universitet, Avdelningen för visuell information och interaktion.
    Mårtensson, Lasse
    Högskolan i Gävle, Akademin för utbildning och ekonomi, Avdelningen för humaniora, Svenska språket och genusvetenskap.
    Brun, Anders
    Uppsala universitet, Avdelningen för visuell information och interaktion.
    Estimating manuscript production dates using both image and language data2016Ingår i: Proceedings of SSBA, 2016, 2016Konferensbidrag (Övrigt vetenskapligt)
  • 1694.
    Wahlberg, Fredrik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion.
    Mårtensson, Lasse
    Univ Gavle, Dept Business Studies, Gavle, Sweden.
    Brun, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Large scale continuous dating of medieval scribes using a combined image and language model2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    Finding the production date of a pre-modern manuscript is commonly a long process in historical research, requiring days of work from highly specialised experts. In this paper, we present an automatic dating method based on modelling both the language and the image data. By creating a statistical model over the changes in the pen strokes and short character sequences in the transcribed text, a combination of multiple estimators give a distribution over the time line for each manuscript. We have evaluated our estimation scheme on the medieval charter collection "Svenskt Diplomatariums huvudkartotek" (SDHK), including more than 5300 transcribed charters from the period 1135 - 1509. Our system is capable of achieving a median absolute error of 12 years, where the only human input is a transcription of the charter text. Since reading and transcribing the text is a skill that many researchers and students have, compared to the more specialized skill of dating medieval manuscripts based on palaeographical expertise, we find our novel approach suitable for helping individual researchers to date collections of manuscript pages. For larger collections, transcriptions could also be collected using crowd sourcing.

  • 1695.
    Wahlberg, Fredrik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Mårtensson, Lasse
    Högskolan i Gävle.
    Brun, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Large scale style based dating of medieval manuscripts2015Ingår i: Proc. 3rd International Workshop on Historical Document Imaging and Processing, New York: ACM Press, 2015, s. 107-114Konferensbidrag (Refereegranskat)
  • 1696.
    Wahlberg, Fredrik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Wilkinson, Tomas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Brun, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Historical Manuscript Production Date Estimation using Deep Convolutional Neural Networks2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    Deep learning has thus far not been used for dating of pre-modern handwritten documents. In this paper, we propose ways of using deep convolutional neural networks (CNNs) to estimate production dates for such manuscripts. In our approach, a CNN can either be used directly for estimating the production date or as a feature learning framework for other regression techniques. We explore the feature learning approach using Gaussian Processes regression and Support Vector Regression.The evaluation is performed on a unique large dataset of over 10000 medieval charters from the Swedish collection Svenskt Diplomatariums huvudkartotek (SDHK). We show that deep learning is applicable to the task of dating documents and that the performance is on average comparable to that of a human expert.

  • 1697.
    Walker, Jens
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    A motion cueing model for mining and forestry simulator platforms based on Model Predictive Control2015Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Oryx Simulations tillverkar simulatorer i huvudsak för gruv- och skogsindustrinvilket används i utbildnings- och marknadsföringssyfte. Simulatorerna använder en röorelseplattform för att spegla hur fordonet i simulatormiljön rör sig. Denna plattform lutar och accelererar föraren för att förstarka upplevelsen. Tidigare har ett så kallat klassiskt washout-filter använts för att kontrollera plattformen som lämnar en del i övrigt att onska vad gäller hur väl fordonets rörelser speglas, hur lätt det ar att justera samt hur det hanterar plattformens begränsningar.

    Detta projekt ämnar producera en modell som väl speglar vinklar,hastigheter och accelerationer samtidigt som den respekterar plattformens gränser. I tillägg till detta bör modellen vara enkel att modifiera och justera. Detta uppnås genom så kallad Model Predictive Control som förutsager hur plattformen kommer röra sig utifrån dess aktuella tillstånd samtidigt som den respekterar de tvång som finns på plattformen direkt i modellen. Då alla parametrar i modellen är faktiska fysiska kvantiteter blir modellen märkbart lättare att justera. En viktig komponent i denna lösning är så kallad tilt coordination vilket består i att substituera lateral/longtudinell acceleration med en komposant av tyngdaccelerationen genom att luta föraren.

    Denna modell konstrueras och implementeras i Matlab och verifieras genom att använda extraherat data från den simulerade miljön. Vi kan se att parametrarna som består av vinklar, rotationella hastigheter och linjära accelerationer speglas väldigt väl, samtidigt som tvången på plattformen respekteras. Dessa tvång kan enkelt modieras for att passa den aktuella simulatorn. Vi ser även att modellen framgångsrikt implementerar tilt coordination i plattformens beteende. I teorin har denna modell väldigt bra prestanda; vad som kvarstår är att implementera den på en rörelseplattform och finjustera modellen.

  • 1698.
    Wallenberg, Marcus
    Linköpings universitet, Institutionen för systemteknik, Bildbehandling. Linköpings universitet, Tekniska högskolan.
    A Single-Camera Gaze Tracker using Controlled Infrared Illumination2009Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats
    Abstract [en]

    Gaze tracking is the estimation of the point in space a person is “looking at”. This is widely used in both diagnostic and interactive applications, such as visual attention studies and human-computer interaction. The most common commercial solution used to track gaze today uses a combination of infrared illumination and one or more cameras. These commercial solutions are reliable and accurate, but often expensive. The aim of this thesis is to construct a simple single-camera gaze tracker from off-the-shelf components. The method used for gaze tracking is based on infrared illumination and a schematic model of the human eye. Based on images of reflections of specific light sources in the surfaces of the eye the user’s gaze point will be estimated. Evaluation is also performed on both the software and hardware components separately, and on the system as a whole. Accuracy is measured in spatial and angular deviation and the result is an average accuracy of approximately one degree on synthetic data and 0.24 to 1.5 degrees on real images at a range of 600 mm.

  • 1699.
    Wallenberg, Marcus
    Linköpings universitet, Institutionen för systemteknik, Datorseende. Linköpings universitet, Tekniska högskolan.
    Components of Embodied Visual Object Recognition: Object Perception and Learning on a Robotic Platform2013Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Object recognition is a skill we as humans often take for granted. Due to our formidable object learning, recognition and generalisation skills, it is sometimes hard to see the multitude of obstacles that need to be overcome in order to replicate this skill in an artificial system. Object recognition is also one of the classical areas of computer vision, and many ways of approaching the problem have been proposed. Recently, visually capable robots and autonomous vehicles have increased the focus on embodied recognition systems and active visual search. These applications demand that systems can learn and adapt to their surroundings, and arrive at decisions in a reasonable amount of time, while maintaining high object recognition performance. Active visual search also means that mechanisms for attention and gaze control are integral to the object recognition procedure. This thesis describes work done on the components necessary for creating an embodied recognition system, specifically in the areas of decision uncertainty estimation, object segmentation from multiple cues, adaptation of stereo vision to a specific platform and setting, and the implementation of the system itself. Contributions include the evaluation of methods and measures for predicting the potential uncertainty reduction that can be obtained from additional views of an object, allowing for adaptive target observations. Also, in order to separate a specific object from other parts of a scene, it is often necessary to combine multiple cues such as colour and depth in order to obtain satisfactory results. Therefore, a method for combining these using channel coding has been evaluated. Finally, in order to make use of three-dimensional spatial structure in recognition, a novel stereo vision algorithm extension along with a framework for automatic stereo tuning have also been investigated. All of these components have been tested and evaluated on a purpose-built embodied recognition platform known as Eddie the Embodied.

  • 1700.
    Wallenberg, Marcus
    Linköpings universitet, Institutionen för systemteknik, Datorseende. Linköpings universitet, Tekniska fakulteten.
    Embodied Visual Object Recognition2017Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Object recognition is a skill we as humans often take for granted. Due to our formidable object learning, recognition and generalisation skills, it is sometimes hard to see the multitude of obstacles that need to be overcome in order to replicate this skill in an artificial system. Object recognition is also one of the classical areas of computer vision, and many ways of approaching the problem have been proposed. Recently, visually capable robots and autonomous vehicles have increased the focus on embodied recognition systems and active visual search. These applications demand that systems can learn and adapt to their surroundings, and arrive at decisions in a reasonable amount of time, while maintaining high object recognition performance. This is especially challenging due to the high dimensionality of image data. In cases where end-to-end learning from pixels to output is needed, mechanisms designed to make inputs tractable are often necessary for less computationally capable embodied systems.Active visual search also means that mechanisms for attention and gaze control are integral to the object recognition procedure. Therefore, the way in which attention mechanisms should be introduced into feature extraction and estimation algorithms must be carefully considered when constructing a recognition system.This thesis describes work done on the components necessary for creating an embodied recognition system, specifically in the areas of decision uncertainty estimation, object segmentation from multiple cues, adaptation of stereo vision to a specific platform and setting, problem-specific feature selection, efficient estimator training and attentional modulation in convolutional neural networks. Contributions include the evaluation of methods and measures for predicting the potential uncertainty reduction that can be obtained from additional views of an object, allowing for adaptive target observations. Also, in order to separate a specific object from other parts of a scene, it is often necessary to combine multiple cues such as colour and depth in order to obtain satisfactory results. Therefore, a method for combining these using channel coding has been evaluated. In order to make use of three-dimensional spatial structure in recognition, a novel stereo vision algorithm extension along with a framework for automatic stereo tuning have also been investigated. Feature selection and efficient discriminant sampling for decision tree-based estimators have also been implemented. Finally, attentional multi-layer modulation of convolutional neural networks for recognition in cluttered scenes has been evaluated. Several of these components have been tested and evaluated on a purpose-built embodied recognition platform known as Eddie the Embodied.

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