Ändra sökning
Avgränsa sökresultatet
28293031323334 1501 - 1550 av 1956
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Träffar per sida
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
Markera
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 1501. Shokoufandeh, Ali
    et al.
    Dickinson, Sven Josef
    Jönsson, Clas
    KTH, Tidigare Institutioner, Numerisk analys och datalogi, NADA.
    On the representation and matching of qualitative shape at multiple scales2002Ingår i: ECCV '02: Proceedings of the 7th European Conference on Computer Vision, 2002, Vol. 2352, s. 759-775Konferensbidrag (Refereegranskat)
    Abstract [en]

    We present a framework for representing and matching multi-scale, qualitative feature hierarchies. The coarse shape of an object is captured by a set of blobs and ridges, representing compact and elongated parts of an object. These parts, in turn, map to nodes in a directed acyclic graph, in which parent/child edges represent feature overlap, sibling edges join nodes with shared parents, and all edges encode geometric relations between the features. Given two feature hierarchies, represented as directed acyclic graphs, we present an algorithm for computing both similarity and node correspondence in the presence of noise and occlusion. Similarity, in turn, is a function of structural similarity, contextual similarity (geometric relations among neighboring nodes), and node contents similarity. Moreover, the weights of these components can be varied on a node by node basis, allowing a graph-based model to effectively parameterize the saliency of its constraints. We demonstrate the approach on two domains: gesture recognition and face detection.

  • 1502. Shokoufandeh, Ali
    et al.
    Dickinson, Sven
    Jönsson, Clas
    Bretzner, Lars
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP.
    Lindeberg, Tony
    KTH, Tidigare Institutioner, Numerisk analys och datalogi, NADA.
    On the Representation and Matching of Qualitative Shape at Multiple Scales2002Ingår i: Computer Vision — ECCV 2002: 7th European Conference on Computer Vision Copenhagen, Denmark, May 28–31, 2002 Proceedings, Part III, Springer Berlin/Heidelberg, 2002, s. 759-775Konferensbidrag (Refereegranskat)
    Abstract [en]

    We present a framework for representing and matching multi-scale, qualitative feature hierarchies. The coarse shape of an object is captured by a set of blobs and ridges, representing compact and elongated parts of an object. These parts, in turn, map to nodes in a directed acyclic graph, in which parent/child edges represent feature overlap, sibling edges join nodes with shared parents, and all edges encode geometric relations between the features. Given two feature hierarchies, represented as directed acyclic graphs, we present an algorithm for computing both similarity and node correspondence in the presence of noise and occlusion. Similarity, in turn, is a function of structural similarity, contextual similarity (geometric relations among neighboring nodes), and node contents similarity. Moreover, the weights of these components can be varied on a node by node basis, allowing a graph-based model to effectively parameterize the saliency of its constraints. We demonstrate the approach on two domains: gesture recognition and face detection.

  • 1503.
    Siadat, Medya
    et al.
    Azarbaijan Shahid Madani Univ, Dept Appl Math, Tabriz 5375171379, Iran..
    Aghazadeh, Nasser
    Azarbaijan Shahid Madani Univ, Dept Appl Math, Tabriz 5375171379, Iran..
    Akbarifard, Farideh
    Azarbaijan Shahid Madani Univ, Dept Appl Math, Tabriz 5375171379, Iran..
    Brismar, Hjalmar
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biofysik. KTH, Centra, Science for Life Laboratory, SciLifeLab. SciLifeLab, Adv Light Microscopy Facil, S-17165 Solna, Sweden..
    Öktem, Ozan
    KTH, Skolan för teknikvetenskap (SCI), Matematik (Inst.), Matematik (Avd.). KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Joint Image Deconvolution and Separation Using Mixed Dictionaries2019Ingår i: IEEE Transactions on Image Processing, ISSN 1057-7149, E-ISSN 1941-0042, Vol. 28, nr 8, s. 3936-3945Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The task of separating an image into distinct components that represent different features plays an important role in many applications. Traditionally, such separation techniques are applied once the image in question has been reconstructed from measured data. We propose an efficient iterative algorithm, where reconstruction is performed jointly with the task of separation. A key assumption is that the image components have different sparse representations. The algorithm is based on a scheme that minimizes a functional composed of a data discrepancy term and the l(1)-norm of the coefficients of the different components with respect to their corresponding dictionaries. The performance is demonstrated for joint 2D deconvolution and separation into curve- and point-like components, and tests are performed on synthetic data as well as experimental stimulated emission depletion and confocal microscopy data. Experiments show that such a joint approach outperforms a sequential approach, where one first deconvolves data and then applies image separation.

  • 1504.
    Sibirtseva, Elena
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Robotik, perception och lärande, RPL.
    Ghadirzadeh, Ali
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Robotik, perception och lärande, RPL. Intelligent Robotics Research Group, Aalto University, Espoo, Finland.
    Leite, Iolanda
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Robotik, perception och lärande, RPL.
    Björkman, Mårten
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Robotik, perception och lärande, RPL.
    Kragic, Danica
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Robotik, perception och lärande, RPL.
    Exploring Temporal Dependencies in Multimodal Referring Expressions with Mixed Reality2019Ingår i: Virtual, Augmented and Mixed Reality. Multimodal Interaction 11th International Conference, VAMR 2019, Held as Part of the 21st HCI International Conference, HCII 2019, Orlando, FL, USA, July 26–31, 2019, Proceedings, Springer Verlag , 2019, s. 108-123Konferensbidrag (Refereegranskat)
    Abstract [en]

    In collaborative tasks, people rely both on verbal and non-verbal cues simultaneously to communicate with each other. For human-robot interaction to run smoothly and naturally, a robot should be equipped with the ability to robustly disambiguate referring expressions. In this work, we propose a model that can disambiguate multimodal fetching requests using modalities such as head movements, hand gestures, and speech. We analysed the acquired data from mixed reality experiments and formulated a hypothesis that modelling temporal dependencies of events in these three modalities increases the model’s predictive power. We evaluated our model on a Bayesian framework to interpret referring expressions with and without exploiting the temporal prior.

  • 1505.
    Sigfridsson, Andreas
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska högskolan.
    Multidimensional MRI of Cardiac Motion: Acquisition, Reconstruction and Visualization2006Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Methods for measuring deformation and motion of the human heart in-vivo are crucial in the assessment of cardiac function. Applications ranging from basic physiological research, through early detection of disease to follow-up studies, all benefit from improved methods of measuring the dynamics of the heart. This thesis presents new methods for acquisition, reconstruction and visualization of cardiac motion and deformation, based on magnetic resonance imaging.

    Local heart wall deformation can be quantified in a strain rate tensor field. This tensor field describes the local deformation excluding rigid body translation and rotation. The drawback of studying this tensor-valued quantity, as opposed to a velocity vector field, is the high dimensionality of the tensor. The problem of visualizing the tensor field is approached by combining a local visualization that displays all degrees of freedom for a single tensor with an overview visualization using a scalar field representation of the complete tensor field. The scalar field is obtained by iterated adaptive filtering of a noise field.

    Several methods for synchronizing the magnetic resonance imaging acquisition to the heart beat have previously been used to resolve individual heart phases from multiple cardiac cycles. In the present work, one of these techniques is extended to resolve two temporal dimensions simultaneously, the cardiac cycle and the respiratory cycle. This is combined with volumetric imaging to produce a five-dimensional data set. Furthermore, the acquisition order is optimized in order to reduce eddy current artifacts.

    The five-dimensional acquisition either requires very long scan times or can only provide low spatiotemporal resolution. A method that exploits the variation in temporal bandwidth over the imaging volume, k-t BLAST, is described and extended to two simultaneous temporal dimensions. The new method, k-t2 BLAST, allows simultaneous reduction of scan time and improvement of spatial resolution.

  • 1506.
    Simberg, Gustav
    et al.
    Linköpings universitet, Institutionen för systemteknik.
    Viggeborn, Björn
    Linköpings universitet, Institutionen för systemteknik.
    Utveckling av mobiltelefonapplikation för kommunikation i ad-hoc nätverk med Bluetoothteknik2005Självständigt arbete på avancerad nivå (magisterexamen), 20 poäng / 30 hpStudentuppsats
    Abstract [en]

    The purpose of this thesis is to develop an application for mobile phones that simplifies communication. The company Doberman wanted to look at possibilities to develop such an application that uses Bluetooth™ technol-ogy to communicate in ad-hoc networks. The aim has been an application to run on mobile phones in which you can send messages and files to other devices and also add a user profile with personal information to share with others. The communication will take place in temporary networks created when Bluetooth enabled devices is in range of each other.

    The market for mobile phones has grown rapidly over the past years and is still growing. There are many differ-ent phone models and it is difficult to find a developer platform that covers many phone models. In the beginning of this thesis an inquiry of different developer platforms has been made. The Java™ platform is supported by most phones but has limitations in accessing functions on the device. The best alternative was Symbian C++ for devices with Symbian OS. This alternative does not have the same limitations as Java and is still supported by relatively many devices. The application was then developed in Symbian C++. There are a number of different versions of Symbian OS and different GUI-platforms that runs on Symbian OS which leads to other issues in the development. We have limited the development of the application to the Series 60 platform for Symbian OS v7.0s. During design and implementation portability to other GUI-platforms has been considered.

    We have tested the application on emulator compatible with Symbian OS v7.0s and Symbian OS v8.0a and found some compatibility problems between the two versions. We have also tested the application on mobile phones and between emulator and the phone with corresponding OS-version no new problems occurred

  • 1507.
    Simoens, Pieter
    et al.
    IDLab, Ghent University – imec, Ghent, Belgium.
    Dragone, Mauro
    Research Institute of Signals, Sensors and Systems (ISSS), Heriot-Watt University, Edinburgh, United Kingdom.
    Saffiotti, Alessandro
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    The Internet of Robotic Things: A review of concept, added value and applications2018Ingår i: International Journal of Advanced Robotic Systems, ISSN 1729-8806, E-ISSN 1729-8814, Vol. 15, nr 1, artikel-id 1729881418759424Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    The Internet of Robotic Things is an emerging vision that brings together pervasive sensors and objects with robotic and autonomous systems. This survey examines how the merger of robotic and Internet of Things technologies will advance the abilities of both the current Internet of Things and the current robotic systems, thus enabling the creation of new, potentially disruptive services. We discuss some of the new technological challenges created by this merger and conclude that a truly holistic view is needed but currently lacking.

  • 1508.
    Sintorn, I.
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Automatic identification and classification of Cytomegalovirus capsids in electron micrographs2002Ingår i: Proc. Medicintekniska konferensen, Huddinge, Stockholm, 8-9 oktober, 2002., 2002Konferensbidrag (Övrigt vetenskapligt)
  • 1509.
    Sintorn, Ida-Maria
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Object decomposition based on grey-level and shape information2004Ingår i: Proc. Swedish Society for Automated Image Analysis (SSBA) Symposium 2004, 2004, s. 25-Konferensbidrag (Övrigt vetenskapligt)
  • 1510.
    Sintorn, Ida-Maria
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys.
    Bischof, Leanne
    CSIRO Mathematical and Information Sciences.
    Buckley, Michael
    CSIRO Mathematical and Information Sciences.
    Jackway, Paul
    CSIRO Mathematical and Information Sciences.
    Haggarty, Stephen
    BROAD Institute of Harvard and MIT.
    Gradient based intensity normalization2010Ingår i: Journal of Microscopy, ISSN 0022-2720, E-ISSN 1365-2818, Vol. 240, nr 3, s. 249-258Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Intensity normalization is important in quantitative image analysis, especially when extracting features based on intensity. In automated microscopy, particularly in large cellular screening experiments, each image contains objects of similar type (e.g. cells) but the object density (number and size of the objects) may vary markedly from image to image. Standard intensity normalization methods, such as matching the grey-value histogram of an image to a target histogram from, i.e. a reference image, only work well if both object type and object density are similar in the images to be matched. This is typically not the case in cellular screening and many other types of images where object type varies little from image to image, but object density may vary dramatically. In this paper, we propose an improved form of intensity normalization which uses grey-value as well as gradient information. This method is very robust to differences in object density. We compare and contrast our method with standard histogram normalization across a range of image types, and show that the modified procedure performs much better when object density varies between images.

  • 1511.
    Sintorn, Ida-Maria
    et al.
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Borgefors, Gunilla
    Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Weighted distance transforms for images using elongated voxel grids2002Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper we investigate weighted distance transforms in 3D images using elongated voxel grids. We use a local neighbourhood of size 3x3x3 and assume a voxel grid with equal resolution along two axes and lower along the third. The weights (local dista

  • 1512.
    Sintorn, Ida-Maria
    et al.
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Borgefors, Gunilla
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Weighted distance transforms for volume images digitized in elongated voxel grids2004Ingår i: Pattern Recognition Letters, Vol. 25, s. 571-580Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Weighted distance transforms in volume (3D) images using a voxel grid with equal resolution along two axes

    and lower, one, along the third are investigated. The weights (neighbour distances) in a local neighbourhoo

    d of size 3 x 3 x 3 are optimized by minimizing the maximum error in a cubic image.

  • 1513.
    Sintorn, Ida-Maria
    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.
    Gedda, Magnus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys.
    Svensson, Stina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys.
    Mata, Susana
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys.
    Medial grey-level based representation for proteins in volume images2005Ingår i: Pattern Recognition and Image Analysis: Second Iberian Conference (IbPRIA 2005), Proceedings, Part II, 2005, s. 421-428Konferensbidrag (Refereegranskat)
    Abstract [en]

    We present an algorithm to extract a medial representation of proteins in volume images. The representation (MGR) takes into account the internal grey-level distribution of the protein and can be extracted without first segmenting the image into object and background. We show how MGR can facilitate the analysis of the structure of the proteins and thereby also classification. Results are shown on two types of protein images.

  • 1514.
    Sintorn, Ida-Maria
    et al.
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Homman, Mohammed
    Description, Segmentation and Classification of Human Cytomegalovirus Capsids2002Ingår i: Proceedings SSAB'02 Symposium on Image Analysis, 2002, s. 21-24Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Three stages in the capsid assembly of Human Cytomegalovirus in the host cell nucleus are investigated. The classes are described by a radial grey-level profile constructed for each class. A segmentation and classification method, based on matching of tem

  • 1515.
    Sintorn, Ida-Maria
    et al.
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Homman-Loudiyi, Mohammed
    Söderberg-Nauclér, Cecilia
    Borgefors, Gunilla
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    A refined circular template matching method for classification of human cytomegalovirus capsids in TEM images2004Ingår i: Computer Methods and Programs in Biomedicine, Vol. 76, s. 95-102Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An automatic image analysis method for describing, segmenting, and classifying Human Cyto\-megalo\-virus c

    apsids in transmission electron micrograph (TEM) images of host cell nuclei has been developed. Three stage

    s of the capsid assembly process in the host cell nucleus have been investigated. Each class is described b

    y a radial density profile, which is the average grey-level at each radial distance from the centre. A temp

    late, constructed from the profile, is used to find possible capsid locations by correlation based matching

    . The matching results are further refined by size and distortion analysis of each possible capsid, resulti

    ng in a final segmentation and classification.

  • 1516.
    Sintorn, Ida-Maria
    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.
    Kylberg, Gustaf
    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.
    Regional Zernike Moments for Texture Recognition2012Ingår i: Proceedings of the 21st International Conference on Pattern Recognition (ICPR), 2012, s. 1635-1638Konferensbidrag (Refereegranskat)
    Abstract [en]

     Zernike moments are commonly used in pattern recognition but are not suited for texture analysis. In this paper we introduce regional Zernike moments (RZM) where we combine the Zernike moments for the pixels in a region to create a measure suitable for texture analysis. We compare our proposed measures to texture measures based on Gabor filters, Haralick co-occurrence matrices and local binary patterns on two different texture image sets, and show that they are noise insensitive and very well suited for texture recognition.

  • 1517.
    Sintorn, Ida-Maria
    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. Uppsala universitet, Science for Life Laboratory, SciLifeLab.
    Kylberg, Gustaf
    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.
    Virus recognition based on local texture2014Ingår i: Proceedings 22nd International Conference on Pattern Recognition (ICPR), 2014, 2014, s. 3227-3232Konferensbidrag (Refereegranskat)
    Abstract [en]

    To detect and identify viruses in electron microscopy images is crucial in certain clinical emergency situations. It is currently a highly manual task, requiring an expert sittingat the microscope to perform the analysis visually. Here wefocus on and investigate one aspect towards automating the virusdiagnostic task, namely recognizing the virus type based on theirtexture once possible virus objects have been segmented. Weshow that by using only local texture descriptors we achievea classification rate of almost 89% on texture patches from 15different virus types and a debris (false object) class. We compareand combine 5 different types of local texture descriptors andshow that by combining the different types a lower classificationerror is achieved. We use a Random Forest Classifier and comparetwo approaches for feature selection.

  • 1518.
    Sintorn, Ida-Maria
    et al.
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Mata, Susana
    Using grey-level and shape information for decomposing proteins in 3D images2004Ingår i: IEEE International, 2004, s. 800-803Konferensbidrag (Refereegranskat)
    Abstract [en]

    An image analysis method for decomposing 3D objects using a combination

    of grey-level and shape is presented. The method consists of two major p

    arts: seeding based on grey-level information and growth from the seeds

    based on shape information. The growth is performed in two steps in orde

    r to prevent seeds located in peripheral or protruding parts of the obje

    ct from growing into other parts. The method was developed to decompose

    3D reconstructions of proteins into their structural subunits. The prote

    ins are imaged with SET (Sidec Electron Tomography) at a resolution of a

    pproximately 2nm, and delineated from the background by thresholding pri

    or to application of our decomposition method. Decomposition can be a us

    eful tool in the second step of the segmentation process to help disting

    uish between true protein molecules and other objects. It can also be us

    eful for analyzing and visualizing interactions between proteins.

  • 1519.
    Sintorn, Ida-Maria
    et al.
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Svensson, Stina
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Axelsson, Maria
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Borgefors, Gunilla
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Segmentation of individual pores in 3D paper images2005Ingår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, Vol. 20, nr 3, s. 316-319Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, we show that the void space in 3D images of paper can be successfully divided into subspaces using digital volume image analysis. The subspaces are denoted pores, which are connected to each other by contractions or narrowings, throats. This division of the void space into individual pores opens the possibility of extracting geometrical features as well as localising where pores with a certain feature are located in the paper. The method is illustrated on a 3D reconstruction from 2D Scanning Electron Microscopy images of a five layered duplex board. Examples of easily extracted features for the segmented pores and plots for some pore features versus the position in the paper are presented.

  • 1520.
    Sintorn, I.-M.
    et al.
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Borgefors, G.
    Weighted Distance Transforms in Rectangular Grids2001Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper we have investigated weighted distance transforms in 2D images in

  • 1521. Siozios, K.
    et al.
    Diamantopoulos, D.
    Kostavelis, Ioannis
    Production and Management Engineering Dept., Democritus University of Thrace, Greece.
    Boukas, Evangelos
    Production and Management Engineering Dept., Democritus University of Thrace, Greece.
    Nalpantidis, Lazaros
    Production and Management Engineering Dept., Democritus University of Thrace, Greece.
    Soudris, D.
    Gasteratos, Antonios
    Production and Management Engineering Dept., Democritus University of Thrace, Greece.
    Aviles, M.
    Anagnostopoulos, I.
    SPARTAN project: Efficient implementation of computer vision algorithms onto reconfigurable platform targeting to space applications2011Ingår i: 6th International Workshop on Reconfigurable Communication-Centric Systems-on-Chip, ReCoSoC 2011 - Proceedings, 2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    Vision-based robotic applications exhibit increased computational complexity. This problem becomes even more important regarding mission critical application domains. The SPARTAN project focuses in the tight and optimal implementation of computer vision algorithms targeting to rover navigation for space applications. For evaluation purposes, these algorithms will be implemented with a co-design methodology onto a Virtex-6 FPGA device.

  • 1522.
    Sjanic, Zoran
    et al.
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska högskolan.
    Gustafsson, Fredrik
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska fakulteten.
    Simultaneous Navigation and Synthetic Aperture Radar Focusing2015Ingår i: IEEE Transactions on Aerospace and Electronic Systems, ISSN 0018-9251, E-ISSN 1557-9603, Vol. 51, nr 2, s. 1253-1266Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Synthetic aperture radar (SAR) equipment is a radar imaging system that can be used to create high-resolution images of a scene by utilizing the movement of a flying platform. Knowledge of the platforms trajectory is essential to get good and focused images. An emerging application field is real-time SAR imaging using small and cheap platforms where estimation errors in navigation systems imply unfocused images. This contribution investigates a joint estimation of the trajectory and SAR image. Starting with a nominal trajectory, we successively improve the image by optimizing a focus measure and updating the trajectory accordingly. The method is illustrated using simulations using typical navigation performance of an unmanned aerial vehicle. One real data set is used to show feasibility, where the result indicates that, in particular, the azimuth position error is decreased as the image focus is iteratively improved.

  • 1523.
    Sjödahl, Mikael
    et al.
    Luleå University of Technology, Lkuleå, Sweden.
    Hallstig, Emil
    Optronic, Sekellefteå, Sweden.
    Khodadad, Davood
    Luleå University of Technology, Lkuleå, Sweden.
    Multi-spectral speckles: theory and applications2012Ingår i: Speckle 2012: V International Conference on Speckle Metrology / [ed] Ángel Fernandez Doval & Cristina Trillo, SPIE - International Society for Optical Engineering, 2012, Vol. 8413, artikel-id 841306Konferensbidrag (Refereegranskat)
    Abstract [en]

    The objective of this paper is to discuss the properties and a few applications of multi-spectral speckles. The paper starts with a theoretical section where the correlation properties of multi-spectral speckles are detailed for the case of reflective imaging geometry. Both a free-space geometry and an imaging geometry are detailed. As an application example effects and possibilities provided by the theory in a measurement of surface shape of a generally shaped object from a dual-wavelength holographic recording are detailed. It is showed that the same phase profile is obtained from integration of speckle movements and phase unwrapping and they are therefore exchangeable quantities.

  • 1524.
    Sjöholm, Alexander
    Linköpings universitet, Institutionen för systemteknik, Datorseende. Linköpings universitet, Tekniska högskolan.
    Closing the Loop: Mobile Visual Location Recognition2014Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Visual simultaneous localization and mapping (SLAM) as field has been researched for ten years, but with recent advances in mobile performance visual SLAM is entering the consumer market in a completely new way. A visual SLAM system will however be sensitive to non cautious use that may result in severe motion, occlusion or poor surroundings in terms of visual features that will cause the system to temporarily fail. The procedure of recovering from such a fail is called relocalization. Together with two similar problems localization, to find your position in an existing SLAM session, and loop closing, the online reparation and perfection of the map in an active SLAM session, these can be grouped as visual location recognition (VLR).

    This thesis presents novel results by combining the scalability of FabMap and the precision of 13th Lab's tracking yielding high-precision VLR, +/- 10 cm, while maintaining above 99 % precision and 60 % recall for sessions containing thousands of images. Everything functional purely on a normal mobile phone.

    The applications of VLR are many. Indoors, where GPS is not functioning, VLR can still provide positional information and navigate you through big complexes like airports and museums. Outdoors, VLR can improve the precision of GPS tenfold yielding a new level of navigational experience. Virtual and augmented reality applications are other areas that benefit from improved positioning and localization.

  • 1525.
    Sjöholm, Daniel
    KTH, Skolan för datavetenskap och kommunikation (CSC).
    Calibration using a general homogeneous depth camera model2017Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Att noggrant kunna mäta avstånd i djupbilder är viktigt för att kunna göra bra rekonstruktioner av objekt. Men denna mätprocess är brusig och dagens djupsensorer tjänar på ytterligare korrektion efter fabrikskalibrering. Vi betraktar paret av en djupsensor och en bildsensor som en enda enhet som returnerar komplett 3D information. 3D informationen byggs upp från de två sensorerna genom att lita på den mer precisa bildsensorn för allt förutom djupmätningen. Vi presenterar en ny linjär metod för att korrigera djupdistorsion med hjälp av en empirisk modell, baserad kring att enbart förändra djupdatan medan plana ytor behålls plana. Djupdistortionsmodellen implementerades och testades på kameratypen Intel RealSense SR300. Resultaten visar att modellen fungerar och i regel minskar mätfelet i djupled efter kalibrering, med en genomsnittlig förbättring kring 50 procent för de testade dataseten.

  • 1526.
    Sjöström, Mårten
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Härdling, Peter
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Karlsson, Linda S.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Olsson, Roger
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Improved Depth-Image-Based Rendering Algorithm2011Ingår i: 3DTV Conference: The True Vision - Capture, Transmission and Display of 3D Video, 3DTV-CON 2011 - Proceedings, IEEE conference proceedings, 2011, s. Art. no. 5877183-Konferensbidrag (Refereegranskat)
    Abstract [en]

    The present work analyses a layered depth-image-based-rendering algorithm based on possible errors occurring with perspective 3D warping. The outcome is improvements to the algorithm that treats depth reliably for scenes containing several levels of foreground objects. The filling of holes of different kinds is addressed so that results have better visual quality. The analysis compares the results of the algorithm with a reference algorithm for the potential error types, and visual examples exhibit the consequences of the improvements. Different objective metrics give ambiguous results, which may be explained by the reduction of structure caused by the reference algorithm.

  • 1527.
    Sjöö, Kristoffer
    et al.
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP.
    Zender, Hendrik
    Jensfelt, Patric
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP.
    Kruijff, Geert-Jan M.
    Pronobis, Andrzej
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP.
    Hawes, Nick
    Brenner, Michael
    The explorer system2010Ingår i: Cognitive Systems Monographs: Cognitive Systems / [ed] H. I. Christensen, G.-J. M. Kruijff, J. L. Wyatt, Springer Berlin/Heidelberg, 2010, 8, s. 395-421Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    In the Explorer scenario we deal with the problems of modeling space, acting in this space and reasoning about it. Spatial models are built using input from sensors such as laser scanners and cameras but equally importantly also based on human input. It is this combination that enables the creation of a spatial model that can support low level tasks such as navigation, as well as interaction. Even combined, the inputs only provide a partial description of the world. By combining this knowledge with a reasoning system and a common sense ontology, further information can be inferred to make the description of the world more complete. Unlike the PlayMate system, all the information that is needed to build the spatial models are not available to it sensors at all times. The Explorer need to move around, i.e. explorer space, to gather information and integrate this into the spatial models. Two main modes for this exploration of space have been investigated within the Explorer scenario. In the first mode the robot explores space together with a user in a home tour fashion. That is, the user shows the robot around their shared environment. This is what we call the Human Augmented Mapping paradigm. The second mode is fully autonomous exploration where the robot moves with the purpose of covering space. In practice the two modes would both be used interchangeably to get the best trade-off between autonomy, shared representation and speed. The focus in the Explorer is not on performing a particular task to perfection, but rather acting within a flexible framework that alleviates the need for scripting and hardwiring. We want to investigate two problems within this context: what information must be exchanged by different parts of the system to make this possible, and how the current state of the world should be represented during such exchanges. One particular interaction which encompasses a lot of the aforementioned issues is giving the robot the ability to talk about space. This interaction raises questions such as:  how can we design models that allow the robot and human to talk about where things are, and how do we link the dialogue and the mapping systems?

  • 1528.
    Skoglund, Johan
    Linköpings universitet, Institutionen för systemteknik, Bildbehandling. Linköpings universitet, Tekniska högskolan.
    Robust Real-Time Estimation of Region Displacements in Video Sequences2007Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The possibility to use real-time computer vision in video sequences gives many opportunities for a system to interact with the environment. Possible ways for interaction are e.g. augmented reality like in the MATRIS project where the purpose is to add new objects into the video sequence, or surveillance where the purpose is to find abnormal events.

    The increase of the speed of computers the last years has simplified this process and it is now possible to use at least some of the more advanced computer vision algorithms that are available. The computational speed of computers is however still a problem, for an efficient real-time system efficient code and methods are necessary. This thesis deals with both problems, one part is about efficient implementations using single instruction multiple data (SIMD) instructions and one part is about robust tracking.

    An efficient real-time system requires efficient implementations of the used computer vision methods. Efficient implementations requires knowledge about the CPU and the possibilities given. In this thesis, one method called SIMD is explained. SIMD is useful when the same operation is applied to multiple data which usually is the case in computer vision, the same operation is executed on each pixel.

    Following the position of a feature or object in a video sequence is called tracking. Tracking can be used for a number of applications. The application in this thesis is to use tracking for pose estimation. One way to do tracking is to cut out a small region around the feature, creating a patch and find the position on this patch in the other frames. To find the position, a measure of the difference between the patch and the image in a given position is used. This thesis thoroughly investigates the sum of absolute difference (SAD) error measure. The investigation involves different ways to improve the robustness and to decrease the average error. One method to estimate the average error, the covariance of the position error is proposed. An estimate of the average error is needed when different measurements are combined.

    Finally, a system for camera pose estimation is presented. The computer vision part of this system is based on the result in this thesis. This presentation contains also a discussion about the result of this system.

  • 1529.
    Sladoje, Natasa
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    A Brief Review on Benno Artman's "Euclid - The Creation of Mathematics"2005Rapport (Övrigt vetenskapligt)
    Abstract
  • 1530.
    Sladoje, Natasa
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    A report on 10th Summer School on Image Processing2002Rapport (Övrigt vetenskapligt)
    Abstract
  • 1531.
    Sladoje, Natasa
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Review of scientific papers on fuzzy shape analysis2005Rapport (Övrigt vetenskapligt)
  • 1532.
    Sladoje, Natasa
    Uppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Reviews on Scientific Papers on Application of Fuzzy Set Theory in Image Segmentation2002Rapport (Övrigt vetenskapligt)
  • 1533.
    Sladoje, Natasa
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys. Faculty of Technical Sciences, University of Novi Sad.
    The Reconstruction of the Digital Hyperbola Segment from Its Code2000Ingår i: International Conference on Discrete Geometry for Computer Imagery / [ed] Borgefors G., Nyström I., di Baja G.S., Berlin, Heidelberg: Springer Berlin/Heidelberg, 2000, s. 159-170Konferensbidrag (Refereegranskat)
  • 1534.
    Sladoje, Natasa
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Mathematical Institute, Serbian Academy of Sciences and Arts, Belgrade, Serbia.
    Lindblad, Joakim
    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. Mathematical Institute, Serbian Academy of Sciences and Arts, Belgrade, Serbia.
    Distance Between Vector-Valued Representations of Objects in Images with Application in Object Detection and Classification2017Ingår i: In Proc. of the 18th International Workshop on Combinatorial Image Analysis, IWCIA2017 / [ed] Brimkov, Valentin E. & Barneva, Reneta P., Springer, 2017, Vol. 10256, s. 243-255Konferensbidrag (Refereegranskat)
    Abstract [en]

    We present a novel approach to measuring distances between objects in images, suitable for information-rich object representations which simultaneously capture several properties in each image pixel. Multiple spatial fuzzy sets on the image domain, unified in a vector-valued fuzzy set, are used to model such representations. Distance between such sets is based on a novel point-to-set distance suitable for vector-valued fuzzy representations. The proposed set distance may be applied in, e.g., template matching and object classification, with an advantage that a number of object features are simultaneously considered. The distance measure is of linear time complexity w.r.t. the number of pixels in the image. We evaluate the performance of the proposed measure in template matching in presence of noise, as well as in object detection and classification in low resolution Transmission Electron Microscopy images.

  • 1535.
    Sladoje, Natasa
    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.
    Lindblad, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Estimation of moments of digitized objects with fuzzy borders2005Ingår i: Proc. of 13th International Conference on Image Analysis and Processing: Cagliari, Italy / [ed] Roli F., Vitulano S., Springer, 2005, Vol. 3617, s. 188-195Konferensbidrag (Refereegranskat)
    Abstract [en]

    Error bounds for estimation of moments from a fuzzy representation of a shape are derived, and compared with estimations from a crisp representation. It is shown that a fuzzy membership function based on the pixel area coverage provides higher accuracy of the estimates, compared to binary Gauss digitization at the same spatial image resolution. Theoretical results are confirmed by a statistical study of disks and squares, where the moments of the shape, up to order two, are estimated from its fuzzy discrete representation. The errors of the estimates decrease both with increased size of a shape (spatial resolution) and increased membership resolution (number of available grey-levels).

  • 1536.
    Sladoje, Natasa
    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. Faculty of Engineering, University of Novi Sad, Serbia.
    Lindblad, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    High-precision boundary length estimation by utilizing gray-level information2009Ingår i: IEEE Transaction on Pattern Analysis and Machine Intelligence, ISSN 0162-8828, E-ISSN 1939-3539, Vol. 31, nr 2, s. 357-363Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present a novel method that provides an accurate and precise estimate of the length of the boundary (perimeter) of an object by taking into account gray levels on the boundary of the digitization of the same object. Assuming a model where pixel intensity is proportional to the coverage of a pixel, we show that the presented method provides error-free measurements of the length of straight boundary segments in the case of nonquantized pixel values. For a more realistic situation, where pixel values are quantized, we derive optimal estimates that minimize the maximal estimation error. We show that the estimate converges toward a correct value as the number of gray levels tends toward infinity. The method is easy to implement; we provide the complete pseudocode. Since the method utilizes only a small neighborhood, it is very easy to parallelize. We evaluate the estimator on a set of concave and convex shapes with known perimeters, digitized at increasing resolution. In addition, we provide an example of applicability of the method on real images, by suggesting appropriate preprocessing steps and presenting results of a comparison of the suggested method with other local approaches.

  • 1537.
    Sladoje, Natasa
    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. Faculty of Engineering, University of Novi Sad, Serbia.
    Lindblad, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Perimeter estimation based on grey level object representation2008Rapport (Övrigt vetenskapligt)
    Abstract [en]

    We present a novel method that provides an accurate and precise estimate of the length of the boundary (perimeter) of an object, by taking into account gray-levels on the boundary of the digitization of the same object. Assuming a model where pixel intensity is proportional to the coverage of a pixel, we show that the presented method provides error-free measurements of the length of straight boundary segments in the case of non-quantized pixel values. For a more realistic situation, where pixel values are quantized, we derive optimal estimates that minimize the maximal estimation error. We show that the estimate converges toward a correct value as the number of gray-levels tends toward infinity. The method is easy to implement; we provide complete pseudo-code. Since the method utilizes only a small neighborhood, it is very easy to parallelize. We evaluate the estimator on a set of concave and convex shapes with known perimeters, digitized at increasing resolution.

  • 1538.
    Sladoje, Natasa
    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. Faculty of Engineering, University of Novi Sad, Serbia.
    Lindblad, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Pixel Coverage Segmentation for Improved Feature Estimation2009Ingår i: 15th International Conference on Image Analysis and Processing: ICIAP 2009 / [ed] Pasquale Foggia, Carlo Sansone, Mario Vento, Berlin / Heidelberg: Springer , 2009, s. 929-938Konferensbidrag (Refereegranskat)
    Abstract [en]

    By utilizing intensity information available in images, partial coverage of pixels at object borders can be estimated. Such information can, in turn, provide more precise feature estimates. We present a pixel coverage segmentation method which assigns pixel values corresponding to the area of a pixel that is covered by the imaged object(s). Starting from any suitable crisp segmentation, we extract a one-pixel thin 4-connected boundary between the observed image components where a local linear mixture model is used for estimating fractional pixel coverage values. We evaluate the presented segmentation method, as well as its usefulness for subsequent precise feature estimation, on synthetic test objects with increasing levels of noise added. We conclude that for reasonable noise levels the presented method outperforms the achievable results of a perfect crisp segmentation. Finally, we illustrate the application of the suggested method on a real histological colour image.

     

  • 1539.
    Sladoje, Natasa
    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.
    Lindblad, Joakim
    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.
    The coverage model and its use in image processing2012Ingår i: Selected Topics on Image Processing and Cryptology: Zbornik radova (Collection of Papers) / [ed] Miodrag Mihaljević, Belgrade, Serbia: Mathematical Institute of the Serbian Academy of Sciences and Arts , 2012, s. 39-117Kapitel i bok, del av antologi (Refereegranskat)
  • 1540.
    Sladoje, Natasa
    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.
    Lindblad, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    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.
    Defuzzification of discrete objects by optimizing area and perimeter similarity2004Ingår i: Proceedings of International Conference on Pattern Recognition (ICPR 2004), 2004, Vol. 3, s. 526-629Konferensbidrag (Refereegranskat)
    Abstract [en]

    We present a defuzzification method which produces a crisp digital object starting from a fuzzy digital one, while keeping selected properties of them as similar as possible. Our main focus is on defuzzification based on the invariance of perimeter and area measures while taking into account with the membership values. We perform a similarity optimization procedure using on a region growing approach to obtain a crisp object with the desired properties.

  • 1541. Sladoje, Natasa
    et al.
    Lindblad, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Centrum för bildanalys. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Nyström, Ingela
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Centrum för bildanalys. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Defuzzification of spatial fuzzy sets by feature distance minimization2011Ingår i: Image and Vision Computing, ISSN 0262-8856, E-ISSN 1872-8138, Vol. 29, s. 127-141Artikel i tidskrift (Refereegranskat)
    Abstract
  • 1542.
    Sladoje, Natasa
    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.
    Nyström, Ingela
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.
    Saha, Punam K.
    Measuring perimeter and area in low resolution images using a fuzzy approach2003Ingår i: Proceedings of 13th Scandinavian Conference on Image Analysis (SCIA 2003) / [ed] Bigun J., Gustavsson T., 2003, Vol. 2749, s. 853-860Konferensbidrag (Refereegranskat)
    Abstract [en]

    To overcome the problems of low quality of image segmentation, as well as significant loss of the data, it seems promising to retain the data inaccuracies as realistic as possible during the image analysis procedures, instead of making hard decisions in t

  • 1543.
    Sladoje, Natasa
    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.
    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.
    Saha, Punam K.
    Perimeter and Area Estimations of Digitized Objects with Fuzzy Borders2003Ingår i: Proceedings of 11th International Conference on Discrete Geometry for Computer Imagery (DGCI 2003) / [ed] Nyström I., Sanniti di Baja G., Svensson S., Springer, 2003, Vol. 2886, s. 368-377Konferensbidrag (Refereegranskat)
    Abstract [en]

    Fuzzy segmentation methods have been developed in order to reduce the negative effects of the unavoidable loss of data in the digitization process. These methods require the development of new image analysis methods, handling grey-level images. This paper

  • 1544.
    Sladoje, Natasa
    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. Faculty of Technical Sciences, University of Novi Sad.
    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.
    Saha, Punam K.
    Shape Description of Fuzzy Segmented Objects: Area and Perimeter Estimators2003Ingår i: Proceedings of SSAB (Swedish Society for Automated Image Analysis) Symposium on Image Analysis, Stockholm, Sweden, 2003, s. 17-20Konferensbidrag (Övrigt vetenskapligt)
  • 1545.
    Sladoje, Natasa
    et al.
    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.
    Saha, Punam Kumar
    Measurements of digitized objects with fuzzy borders in 2D and 3D2005Ingår i: Image and Vision Computing, ISSN 0262-8856, Vol. 23, nr 2, s. 123-132Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The results of our investigation of several measurements on digitized 2D and 3D objects with fuzzy borders are presented. The performance of surface area, volume, and roundness measure estimators for digitized balls with fuzzy borders is analyzed. The method we suggest provides significant improvement in precision, compared to analogous estimation results obtained on a crisp (hard) segmentation, especially in the case of low resolution images.

  • 1546.
    Sladoje, Nataša
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Centrum för bildanalys. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys. Faculty of Technical Sciences, University of Novi Sad.
    Ellipses estimation from their digitization1997Ingår i: International Conference on Discrete Geometry for Computer Imagery / [ed] Ahronovitz E., Fiorio C., Berlin, Heidelberg: Springer Berlin/Heidelberg, 1997, Vol. 1347, s. 187-198Konferensbidrag (Refereegranskat)
  • 1547. Smedby, Örjan
    et al.
    Bengtsson, EwertUppsala universitet, Fakultetsövergripande enheter, Centrum för bildanalys. Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datoriserad bildanalys.Persson, Anders
    Interaction in medical image analysis and visualization2007Konferensmeddelanden, proceedings (Refereegranskat)
  • 1548.
    Smeraldi, Fabrizio
    et al.
    Högskolan i Halmstad. Swiss Federal Institute of Technology (EPFL-DI), Lausanne, Switzerland.
    Bigun, Josef
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS).
    Gerstner, Wulfram
    Swiss Federal Institute of Technology (EPFL-DI), Lausanne, Switzerland.
    Support vector features and the role of dimensionality in face authentication2002Ingår i: Pattern recognition with support vector machines / [ed] Seong-Whan Lee, Alessandro Verri, Heidelberg: Springer Berlin/Heidelberg, 2002, Vol. LNCS-2388, s. 249-259Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    A study of the dimensionality of the Face Authentication problem using Principal Component Analysis (PCA) and a novel dimensionality reduction algorithm that we call Support Vector Features (SVFs) is presented. Starting from a Gabor feature space, we show that PCA and SVFs identify distinct subspaces with comparable authentication and generalisation performance. Experiments using KNN classifiers and Support Vector Machines (SVMs) on these reduced feature spaces show that the dimensionality at which saturation of the authentication performance is achieved heavily depends on the choice of the classifier. In particular, SVMs involve directions in feature space that carry little variance and therefore appear to be vulnerable to excessive PCA-based compression. © Springer-Verlag Berlin Heidelberg 2002.

  • 1549.
    Solli, Martin
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Digitala Medier. Linköpings universitet, Tekniska högskolan.
    Color Image Retrieval with Bags-of-Emotions2009Ingår i: Proceedings of SSBA 2009, Symposium on image analysis, 2009 / [ed] Josef Bigun, Antanas Verikas, Halmstad, Sweden: Halmstad University , 2009, s. 37-40Konferensbidrag (Övrigt vetenskapligt)
  • 1550.
    Solli, Martin
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap, Digitala Medier.
    Topics in Content Based Image Retrieval: Fonts and Color Emotions2009Licentiatavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    Two novel contributions to Content Based Image Retrieval are presented and discussed. The first is a search engine for font recognition. The intended usage is the search in very large font databases. The input to the search engine is an image of a text line, and the output is the name of the font used when printing the text. After pre-processing and segmentation of the input image, a local approach is used, where features are calculated for individual characters. The method is based on eigenimages calculated from edge filtered character images, which enables compact feature vectors that can be computed rapidly. A system for visualizing the entire font database is also proposed. Applying geometry preserving linear- and non-linear manifold learning methods, the structure of the high-dimensional feature space is mapped to a two-dimensional representation, which can be reorganized into a grid-based display. The performance of the search engine and the visualization tool is illustrated with a large database containing more than 2700 fonts.

    The second contribution is the inclusion of color-based emotion-related properties in image retrieval. The color emotion metric used is derived from psychophysical experiments and uses three scales: activity, weight and heat. It was originally designed for single-color combinations and later extended to include pairs of colors. A modified approach for statistical analysis of color emotions in images, involving transformations of ordinary RGB-histograms, is used for image classification and retrieval. The methods are very fast in feature extraction, and descriptor vectors are very short. This is essential in our application where the intended use is the search in huge image databases containing millions or billions of images. The proposed method is evaluated in psychophysical experiments, using both category scaling and interval scaling. The results show that people in general perceive color emotions for multi-colored images in similar ways, and that observer judgments correlate with derived values.

    Both the font search engine and the emotion based retrieval system are implemented in publicly available search engines. User statistics gathered during a period of 20 respectively 14 months are presented and discussed.

28293031323334 1501 - 1550 av 1956
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf