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  • 351.
    Malmberg, Filip
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Lindblad, Joakim
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Östlund, Catherine
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Almgren, Karin M.
    Department of Fiber and Polymer Technology, Royal Institute of Technology, Stockholm.
    Gamstedt, Kristoffer M.
    An Automated Image Analysis Method for Measuring Fibre Contact in Fibrous and Composite Materials2008In: 13th European Conference on Composite Materials (ECCM), 2008Conference paper (Other academic)
  • 352.
    Malmberg, Filip
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Nyström, Ingela
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Interactive Segmentation with Relaxed Image Foresting Transforms2009In: Proceedings of SSBA 2009, 2009Conference paper (Other academic)
    Abstract [en]

    The Image Foresting Transform (IFT) is a framework for efficient image partitioning, used in interactive segmentation. We propose a modified version of the IFT, and demonstratethat the modified algorithm is more robust to noise while maintaining computational complexity. We also show an application of the method for interactive segmentation ofback muscles in magnetic resonance images, where seedpoints representing object and background are placed repeatedly until a desired segmentation result is obtained.

  • 353.
    Malmberg, Filip
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Nyström, Ingela
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Mehnert, Andrew
    Engstrom, Craig
    Bengtsson, Ewert
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Relaxed Image Foresting Transforms for Interactive Volume Image Segmentation2010In: MEDICAL IMAGING 2010: IMAGE PROCESSING / [ed] Dawant BM, Haynor DR, 2010, Vol. 7623Conference paper (Refereed)
    Abstract [en]

    The image Foresting (IFT) is a framework for image partitioning, commonly used for interactive segmentation. Given an image where a subset of the image elements (seed-points) have been assigned correct segmentation labels, the IFT completes the labeling by computing minimal cost paths from all image elements to the seed-points. Each image element is then given the same label as the closest seed-point. Here, we propose the relaxed IFT (RIFT). This modified version of the IFT features an additional parameter to control the smoothness of the segmentation boundary. The RIFT yields more intuitive segmentation results in the presence of noise and weak edges, while maintaining a low computational complexity. We show an application of the method to the refinement of manual segmentations of a thoracolumbar muscle in magnetic resonance images. The performed study shows that the refined segmentations are qualitatively similar to the manual segmentations, while intra-user variations are reduced by more than 50%.

  • 354.
    Malmberg, Filip
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Vidholm, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Nyström, Ingela
    A 3D live-wire segmentation method for volume images using haptic interaction2006In: Proceedings of Discrete Geometry for Computer Imagery, LNCS, ISSN 0302-9743, Vol. 4245, p. 663-673Article in journal (Refereed)
  • 355.
    Malmberg, Filip
    et al.
    Uppsala University, Interfaculty Units, Centre for Image Analysis. Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Vidholm, Erik
    Uppsala University, Interfaculty Units, Centre for Image Analysis. Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Nyström, Ingela
    Uppsala University, Interfaculty Units, Centre for Image Analysis. Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    A 3D live-wire segmentation method for volume images using haptic interaction2006In: DISCRETE GEOMETRY FOR COMPUTER IMAGERY, PROCEEDINGS 4245, 2006, p. 663-673Conference paper (Refereed)
    Abstract [en]

    Designing interactive segmentation methods for digital volume images is difficult, mainly because efficient 3D interaction is much

    harder to achieve than interaction with 2D images. To overcome this issue, we use a system that combines stereo graphics and haptics to facilitate efficient 3D interaction. We propose a new method, based on the 2D live-wire method, for segmenting volume images. Our method consists of two parts: an interface for drawing 3D live-wire curves onto the boundary of an object in a volume image, and an algorithm for connecting two such curves to create a discrete surface.

  • 356.
    Malmberg, Filip
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Östlund, Catherine
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Borgefors, Gunilla
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Binarization of Phase Contrast Volume Images of Fibrous Materials: A Case Study2009In: Proceedings of International Conference on Computer Vision Theory and Applications (VISAPP 2009), INSTICC Press , 2009, p. 148-153Conference paper (Refereed)
    Abstract [en]

    In this paper, we present a method for segmenting phase contrast volume images of fibrous materials into fibre and background. The method is based on graph cut segmentation, and is tested on high resolution X-ray microtomography volume images of wood fibres in paper an composites. The new method produces better results than a standard method based on edge-preserving smoothing and hysteresis thresholding. The most important improvement is that the proposed method handles thick and collapsed fibres more accurately than previous methods.

  • 357.
    Malmberg, Filip
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Östlund, Catherine
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Borgefors, Gunilla
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Graph Cut Based Segmentation of Phase Contrast Volume Images of Fibrous Materials2008In: Proceedings of Swedish Symposium on Image Analysis (SSBA'08), 2008, p. 131-134Conference paper (Other academic)
  • 358.
    Mehnert, Andrew
    et al.
    The University of Queensland, Brisbane, Australia.
    Bengtsson, Ewert
    Uppsala University, Interfaculty Units, Centre for Image Analysis. Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    McMahon, Kerry
    Greenslopes Private Hospital, Brisbane, Australia.
    Kennedy, Dominic
    Greenslopes Private Hospital, Brisbane, Australia.
    Wilson, Stepehen
    The University of Queensland, Brisbane, Australia.
    Crozier, Stuart
    University of Queensland, Brisbane, Australia.
    Dynamic breast MRI visualised through colour mapping2005In: Proceedings SSBA 2005, 2005, p. 9-12Conference paper (Other scientific)
    Abstract [en]

    The pattern of change of signal intensity over time in contrast enhanced MR images of the breast is a useful indicator of malignancy. In this paper a new pixel mapping method for visualising the time course of the contrast uptake is presented. The method reduces the sequence of images of a single spatial slice over time to a single colour-coded image. This is achieved by fitting a linear-slope model pixel-wise to the slice time series and using the fitted parameters to define modified HSV colour space coordinates. The model parameters are related to the shape of the signal intensity-time curve at each pixel. The effect is that pixels with rapid uptake and significant postcontrast enhancement appear brighter and more saturated, whilst the nature and degree of intermediate and late postcontrast enhancement is reflected in the colour hue. Preliminary results are reported for six subjects with suspicious MRI findings subsequently confirmed by pathology. The results suggest that the method shows promise as a replacement for, or adjunct to, the review of the raw time series data and/or associated difference images in the clinical setting.

  • 359.
    Mehnert, Andrew
    et al.
    The University of Queensland.
    Bengtsson, Ewert
    Uppsala University, Interfaculty Units, Centre for Image Analysis. Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    McMahon, Kerry
    Greenslopes Private Hospital.
    Kennedy, Dominic
    Greenslopes Private Hospital.
    Wilson, Stephen
    The University of Queensland.
    Crozier, Stuart
    The University of Queensland.
    Visualisation of the pattern of contrast enhancement in dynamic breast MRI2005In: WDIC 2005: Workshop Proceedings, 2005Conference paper (Refereed)
    Abstract [en]

    A new pixel-mapping method for visualising contrast uptake in dynamic MR images of the breast is presented. The method reduces the sequence of images of a single spatial slice over time to a single colour-coded image. This is achieved by fitting a linear-slope model pixel-wise to the slice time series and using the fitted parameters to define HSV colour space coordinates. The model parameters are related to the shape of the signal intensity-time curve at each pixel. The effect is that pixels with rapid and significant initial postcontrast enhancement appear brighter and more saturated, whilst the nature and degree of intermediate and late postcontrast enhancement is reflected in the colour hue. Preliminary results are reported for six subjects with suspicious MRI findings subsequently confimed by pathology. The results suggest that the method shows

    promise as a replacement for, or adjunct to, the review of the raw time series data and/or associated difference images in the clinical setting.

  • 360. Mehnert, Andrew
    et al.
    Wildermoth, M
    Crozier, Stuart
    Bengtsson, Ewert
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Kennedy, D
    Two Non-linear Parametric Models of Contrast Enhancement for DCE-MRI of the Breast Amenable to Fitting Using Linear Least Squares2010In: Proceedings 2010 International Conference on Digital Image Computing: Techniques and Applications (DICTA 2010), IEEE Computer Society, Los Alamitos, CA, USA: IEEE Computer Society , 2010, p. 611-616Conference paper (Refereed)
  • 361.
    Moell, M
    et al.
    Uppsala University, Interfaculty Units, Centre for Image Analysis. Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Borgefors, G
    An image analysis method to measure cross-sectional tracheid dimensions on softwood increment cores2001In: WOOD AND FIBER SCIENCE, ISSN 0735-6161, Vol. 33, no 2, p. 200-212Article in journal (Refereed)
    Abstract [en]

    Anatomical properties of wood affect the properties of wood products. Ln this paper, an automated image analysis method for measuring cross-sectional tracheid dimensions of softwood cores is presented. The images used were single slice, confocal reflected

  • 362.
    Moell, MK
    et al.
    Uppsala University, Interfaculty Units, Centre for Image Analysis. Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Donaldson, LA
    Comparison of segmentation methods for digital image analysis of confocal microscope images to measure tracheid cell dimensions2001In: IAWA JOURNAL, ISSN 0928-1541, Vol. 22, no 3, p. 267-288Article in journal (Refereed)
    Abstract [en]

    Image analysis is a common tool for measuring tracheid cell dimensions. When analyzing a digital image of a transverse cross section of wood, one of the initial procedures is that of segmentation. This involves classifying a picture element (pixel) as eit

  • 363.
    Mohammadi, Siavoush, M
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Hast, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Daldorff, Lars K. S.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Astronomy and Space Physics.
    Ericsson, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology.
    Bergman, Jan, E. S.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Thidè, Bo
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Interactive visualization of new electromagnetic quantities2008In: SIGRAD 2008: The Annual SIGRAD Conference Special Theme: Interaction, November 27–28, 2008 Stockholm, Sweden, Linköping University Electronic press , 2008, p. 71-74Conference paper (Refereed)
    Abstract [en]

    Recent development in classical electrodynamics has demonstratedthe usefulness of different rotational and topological modes in theelectromagnetic fields (angular momentum, polarization, vorticityetc.). Unfortunately, the visualization tools available to illustratethese electrodynamic quantities have hitherto been inadequate.Therefore we have developed a VTK and Python based interactivevisualization tool, with working name EMVT (ElectroMagnetic VisualizationTool), targeted at visualizing precisely these modes.In the near future, EMVT will be further developed to visualize andcontrol live antenna systems, where electromagnetic field data isinstantly received, calculated, and visualized from an antenna or asystem of antennas. It will then be possible to see how the antennaproperties change through direct user interaction in real time.

  • 364.
    Monazzam, Azita
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology.
    Razifar, Pasha
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Ide, Susan
    Rugaard Jensen, Michael
    Josephsson, Raymond
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences.
    Blomqvist, Carl
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Oncology.
    Langström, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Bergström, Mats
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmaceutical Biosciences.
    Evaluation of the Hsp90 inhibitor NVP-AUY922 in multicellular tumour spheroids with respect to effects on growth and PET tracer uptake2009In: Nuclear Medicine and Biology, ISSN 0969-8051, E-ISSN 1872-9614, Vol. 36, no 3, p. 335-342Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Molecular targeting has become a prominent concept in cancer treatment and heat shock protein 90 (Hsp90) inhibitors are suggested as promising anticancer drugs. The Hsp90 complex is one of the chaperones that facilitate the refolding of unfolded or misfolded proteins and plays a role for key oncogenic proteins such as Her2, Raf-1, Akt/PKB, and mutant p53. NVP-AUY922 is a novel low-molecular Hsp90 inhibitor, currently under clinical development as an anticancer drug. Disruption of the Hsp90-client protein complexes leads to proteasome-mediated degradation of client proteins and cell death. The aim of the current study was to use a combination of the multicellular tumour spheroid (MTS) model and positron emission tomography (PET) to investigate the effects of NVP-AUY922 on tumour growth and its relation to PET tracer uptake for the selection of appropriate PET tracer. A further aim was to evaluate the concentration and time dependence in the relation between growth inhibition and PET tracer uptake as part of translational imaging activities. METHODS: MTS of two breast cancer cell lines (MCF-7 and BT474), one glioblastoma cell line (U87MG) and one colon carcinoma cell line (HCT116) were prepared. Initially, we investigated MTS growth pattern and (3)H-thymidine incorporation in MTS after continuous exposure to NVP-AUY922 in order to determine dose response. Then the short-term effect of the drug on the four PET tracers 2-[(18)F] fluoro-2-deoxyglucose (FDG), 3'-deoxy-3'-fluorothymidine (FLT), methionine and choline was correlated to the long-term effect (changes in growth pattern) to determine the adequate PET tracer with high predictability. Next, the growth inhibitory effect of different dose schedules was evaluated to determine the optimal dose and time. Finally, the effect of a 2-h exposure to the drug on growth pattern and FDG/FLT uptake was evaluated. RESULTS: A dose-dependent inhibition of growth and decrease of (3)H-thymidine uptake was observed with 100% growth cessation in the dose range 7-52 nM and 50% (3)H-thymidine reduction in the range of 10-23 nM, with the most pronounced effect on BT474 cells. The effect of the drug was best detected by FLT. The results suggested that a complete cessation of growth of the viable cell volume was achieved with about 50% inhibition of FLT uptake 3 days after continuous treatment. Significant growth inhibition was observed at all doses and all exposure time spans. Two-hour exposure to NVP-AUY922 generated a growth inhibition which persisted dose dependently up to 10 days. The uptake of FDG per viable tumour volume was reduced by just 25% with 300 nM treatment of the drug, whereas the FLT uptake decreased up to 75% in correlation with the growth inhibition and recovery. CONCLUSIONS: Our results indicate a prolonged action of NVP-AUY922 in this cell culture, FLT is a suitable tracer for the monitoring of the effect and a FLT PET study within 3 days after treatment can predict the treatment outcome in this model. If relevant in vivo, this information can be used for efficient planning of animal PET studies and later human PET trial.

  • 365.
    Monazzam, Azita
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Oncology. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Endocrine Tumor Biology.
    Razifar, Pasha
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Lindhe, Örjan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Endocrine Tumor Biology.
    Josephsson, Raymond
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences.
    Långström, Bengt
    Bergström, Mats
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmaceutical Biosciences.
    A new, fast and semi-automated size determination method (SASDM) for studying multicellular tumor spheroids2005In: Cancer Cell International, ISSN 1475-2867, E-ISSN 1475-2867, no 5, p. 32-Article in journal (Refereed)
    Abstract [en]

    BACKGROUND:

    Considering the width and importance of using Multicellular Tumor Spheroids (MTS) in oncology research, size determination of MTSs by an accurate and fast method is essential. In the present study an effective, fast and semi-automated method, SASDM, was developed to determinate the size of MTSs. The method was applied and tested in MTSs of three different cell-lines. Frozen section autoradiography and Hemotoxylin Eosin (H&E) staining was used for further confirmation.

    RESULTS:

    SASDM was shown to be effective, user-friendly, and time efficient, and to be more precise than the traditional methods and it was applicable for MTSs of different cell-lines. Furthermore, the results of image analysis showed high correspondence to the results of autoradiography and staining.

    CONCLUSION:

    The combination of assessment of metabolic condition and image analysis in MTSs provides a good model to evaluate the effect of various anti-cancer treatments.

  • 366.
    Monazzma, Azita
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Oncology. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Endocrine Tumor Biology.
    Razifar, Pasha
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Simonsson, Martin
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology.
    Qvarnström, Fredrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology.
    Josephsson, Raymond
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences.
    Blomqvist, Carl
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Oncology.
    Långström, Bengt
    Bergström, Mats
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmaceutical Biosciences.
    Multicellular Tumour Spheroid as a model for evaluation of [18F]FDG as biomarker for breast cancer treatment monitoring2006In: Cancer Cell International, ISSN 1475-2867, E-ISSN 1475-2867, Vol. 6, p. 6-Article in journal (Refereed)
    Abstract [en]

    Background

    In order to explore a pre-clinical method to evaluate if [18F]FDG is valid for monitoring early response, we investigated the uptake of FDG in Multicellular tumour spheroids (MTS) without and with treatment with five routinely used chemotherapy agents in breast cancer.

    Methods

    The response to each anticancer treatment was evaluated by measurement of the [18F]FDG uptake and viable volume of the MTSs after 2 and 3 days of treatment.

    Results

    The effect of Paclitaxel and Docetaxel on [18F]FDG uptake per viable volume was more evident in BT474 (up to 55% decrease) than in MCF-7 (up to 25% decrease).

    Doxorubicin reduced the [18F]FDG uptake per viable volume more noticeable in MCF-7 (25%) than in BT474 MTSs.

    Tamoxifen reduced the [18F]FDG uptake per viable volume only in MCF-7 at the highest dose of 1 μM.

    No effect of Imatinib was observed.

    Conclusion

    MTS was shown to be appropriate to investigate the potential of FDG-PET for early breast cancer treatment monitoring; the treatment effect can be observed before any tumour size changes occur.

    The combination of PET radiotracers and image analysis in MTS provides a good model to evaluate the relationship between tumour volume and the uptake of metabolic tracer before and after chemotherapy. This feature could be used for screening and selecting PET-tracers for early assessment of treatment response.

    In addition, this new method gives a possibility to assess quickly, and in vitro, a good preclinical profile of existing and newly developed anti-cancer drugs.

  • 367.
    Moëll, M.
    et al.
    Uppsala University, Interfaculty Units, Centre for Image Analysis. Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Donaldsson, L.
    A comparison of rapid automatic global thresholding methods for wood images2000In: Symposium on Image Analysis - SSAB 2000, 2000, p. 49-52Conference paper (Other scientific)
  • 368.
    Moëll, Mattias K.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Donaldson, Lloyd A.
    Shading correction methods for digital image analysis of confocal wood images2007In: IAWA Journal, ISSN 0928-1541, Vol. 28, no 3, p. 349-364Article in journal (Refereed)
    Abstract [en]

    Confocal fluorescence microscopy provides a rapid method for acquiringhigh quality optically thin section images of wood suitable for meas-urement of cell dimensions. Single optical slice images of wood mayoccasionally contain artefacts due to differential light absorption causedby variation in the distance between the sample surface and the imagingplane across the field of view. Regional brightness variations, which wecall shading, may cause problems when such images are used for woodcell measurements using digital image analysis, affecting the accuracyof wood cell dimensions. We have compared various shading correctionmethods for confocal microscope images and investigated the effect ofshading on both the classification of cell wall pixels and the resulting celldimension measurements. Severe shading results in significant errors formeasurement of cell wall area, but smaller errors for cell wall thicknessand lumen diameter. Some shading correction methods have unwantedeffects on pixel classification and cell dimensions, while more effectivemethods remove the shading without introducing further artefacts. Theeffect of shading is influenced by choice of thresholding method.

  • 369.
    Moëll, Mattias K.
    et al.
    Uppsala University, Interfaculty Units, Centre for Image Analysis. Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Fujita, Minoru
    Fourier Transform Methods in Image Analysis of Compression Wood at the Cellular Level2004In: IAWA Journal, Vol. 25, no 3, p. 311-324Article in journal (Refereed)
  • 370.
    Musinguzi, Moses
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Bax, Gerhard
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Tickodri-Togboa, Sandy
    Analysis of the IMAPCT of GIS/ICT On Wetland ASSESSMENT2007In: Proceedings of the Conference on Collaborative Research for Technological Development: 16th-21st December 2007 Kampala Uganda, 2007Conference paper (Refereed)
  • 371.
    Musinguzi, Moses
    et al.
    Uppsala University, Interfaculty Units, Centre for Image Analysis.
    Bax, Gerhard
    Uppsala University, Interfaculty Units, Centre for Image Analysis.
    Tickodri-Togboa, Sandy
    Assessment of GIS DATA interoperability in Uganda2007In: Proceedings of the Conference on Collaborative Research for Technological Development: 16th-21st December 2007 Kampala Uganda, 2007Conference paper (Refereed)
  • 372.
    Myerscough, Hannah
    Uppsala University, Interfaculty Units, Centre for Image Analysis. Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    3D visualisation of sonar coverage data2003Report (Other scientific)
    Abstract [en]

    The aim of this paper is to examine whether it is possible

  • 373. Nagy, Benedek
    et al.
    Strand, Robin
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Approximating Euclidean Distance Using Distances based on Neighbourhood Sequences in Non-Standard Three-Dimensional Grids.2006In: Proceedings Combinatorial Image Analysis: 11th International Workshop, IWCIA 2006, 2006, p. 89-100Conference paper (Refereed)
    Abstract [en]

    In image processing, it is often of great importance to have small rotational dependency for distance functions. We present an optimization for distances based on neighbourhood sequences for the face-centered cubic (fcc) and body-centered cubic (bcc) grids. In the optimization, several error functions are used measuring different geometrical properties of the balls obtained when using these distances.

  • 374. Nagy, Benedek
    et al.
    Strand, Robin
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Neighborhood Sequences in the Diamond Grid2008In: Image analysis: from theory to applications, Research Publishing, Singapore, Chennai , 2008, p. 187-195Chapter in book (Other (popular science, discussion, etc.))
    Abstract [en]

    In digital image processing digital distances are useful; distances based on neighborhood sequences are widely used.

    In this paper the diamond grid is considered, that is the three-dimensional grid of Carbon atoms in the diamond crystal. An algorithm to compute a shortest path defined by a neighborhood sequence between any two points in the diamond grid is presented. A formula to compute the distance based on neighborhood sequences is given. A necessary and sufficient condition to have a metric distance function is proved.

  • 375.
    Nagy, Benedek
    et al.
    Faculty of Informatics, University of Debrecen, Debrecen, Hungary.
    Strand, Robin
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Neighborhood Sequences in the Diamond Grid - Algorithms with Four Neighbors2009In: Proceedings, theoretical track, International Workshop on Combinatorial Image Analysis (IWCIA 2009), Mexico, Berlin / Heidelberg: Springer , 2009, p. 109-121Conference paper (Refereed)
    Abstract [en]

    In digital image processing digital distances are useful; distances based on neighborhood sequences are widely used. In this paper the diamond grid is considered, that is the three-dimensional grid of Carbon atoms in the diamond crystal. This grid can be described by four coordinate values using axes of the directions of atomic bonds. In this way the sum of the coordinate values can be either zero or one. An algorithm to compute a shortest path defined by a neighborhood sequence between any two points in the diamond grid is presented. The metric and non-metric properties of some distances based on neighborhood sequences are also discussed. The constrained distance transformation and digital balls obtained by some distance functions are presented.

  • 376.
    Nagy, Benedek
    et al.
    Faculty of Informatics, University of Debrecen, Debrecen, Hungary.
    Strand, Robin
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Neighborhood Sequences in the Diamond Grid: Algorithms with Two and Three Neighbors2009In: International journal of imaging systems and technology (Print), ISSN 0899-9457, E-ISSN 1098-1098, Vol. 19, no 2, p. 146-157Article in journal (Refereed)
    Abstract [en]

    In the digital image processing, digital distances are useful; distances based on neighborhood sequences are widely used. In this article, the diamond grid is considered, that is, the three-dimensional grid of carbon atoms in the diamond crystal. An algorithm to compute a shortest path defined by a neighborhood sequence between any two points in the diamond grid is presented. A formula to compute the distance based on neighborhood sequences with two neighborhood relations is given. The metric and nonmetric properties of some distances based on neighborhood sequences are also discussed. Finally, the constrained distance transformation is shown.

  • 377.
    Nagy, Benedek
    et al.
    Faculty of Informatics, University of Debrecen, Debrecen, Hungary.
    Strand, Robin
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Neighborhood Sequences on nD Hexagonal/Face-Centered-Cubic Grids2009In: Proceedings, theoretical track, International Workshop on Combinatorial Image Analysis (IWCIA 2009), Mexico, Berlin / Heidelberg: Springer , 2009, p. 96-108Conference paper (Refereed)
    Abstract [en]

    The two-dimensional hexagonal grid and the three-dimensional face-centered cubic grid can be described by intersecting Z3 and Z4 with a (hyper)plane. Corresponding grids in higher dimensions (nD) are examined. In this paper, we define distance functions based on neighborhood sequences on these, higher dimensional generalizations of the hexagonal grid. An algorithm to produce a shortest path based on neighborhood sequences between any two gridpoints is presented. A formula to compute distance and condition of metricity are presented for neighborhood sequences using two types of neighbors. Distance transform as an application of these distances is also shown.

  • 378.
    Niazi, M Khalid Khan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Hedrich, Jens
    Ingela, Nyström
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Image Registration using Particle swarm optimization approach2010In: Symposium on Image Analysis / [ed] Cris Luengo and Milan Gavrilovic, 2010, p. 31-34Conference paper (Other academic)
  • 379.
    Niazi, M Khalid Khan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Nyström, Ingela
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    A Modified Particle Swarm Optimization Applied in Image Registration2010In: Proceedings of 20th International Conference on Pattern Recognition, IEEE computer society , 2010, p. 2302-2305Conference paper (Refereed)
  • 380.
    Niazi, Muhammad Khalid Khan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Bengtsson, Ewert
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Measuring Heart Rate from Rat Embryo Videos2008In: Swedish Symposium on Image Analysis, Lund, Sweden: Swedish Society for Automated Image Analysis , 2008, p. 35-38Conference paper (Other academic)
    Abstract [en]

     

    Embryo cultures of rodents is an established technique for monitoring adverse e®ects of chemicals on embryonic development. The assessment involves determination of the heart rate of the embryo which is usually done visually, a technique which is tedious and error prone. We present a new method for fully automatic heart detection in digital videos of mouse or rat embryos. First it detects the heart location, and then it counts the number of heart beats for a predetermined period of time.

     

  • 381.
    Niazi, Muhammad Khalid Khan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Nilsson, Mats
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmaceutical Biosciences.
    Danielsson, Bengt R.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmaceutical Biosciences.
    Bengtsson, Ewert
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Fully Automatic Heart Beat Rate Determination in Digital Video Recordings of Rat Embryos2009In: Transactions on Mass-Data Analysis of Images and Signals, ISSN 1868-6451, Vol. 1, no 2, p. 132-146Article in journal (Refereed)
    Abstract [en]

    Embryo cultures of rodents is an established technique for monitoring adverse effects of chemicals on embryonic development. The assessment involves determination of the heart rate of the embryo which is usually done visually, a technique which is tedious and error prone. We present a new method for fully automatic heart detection in digital videos of rat embryos. First it detects the heart location by using decimation free directional filter bank along with first absolute moment, and then it counts the number of heart beats for a predetermined period of time. Using this automated method many more embryos can be evaluated at reasonable cost.

  • 382.
    Niazi, Muhammad Khalid Khan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Nilsson, Mats F.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmaceutical Biosciences.
    Danielsson, Bengt R.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmaceutical Biosciences.
    Bengtsson, Ewert
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Fully Automatic Heart Beat Rate Determination in Digital Video Recordings of Rat Embryos2008In: ADVANCES IN MASS DATA ANALYSIS OF IMAGES AND SIGNALS IN MEDICINE, BIOTECHNOLOGY, CHEMISTRY AND FOOD INDUSTRY, PRCEEDINGS / [ed] Perner P, Salvetti O, 2008, p. 27-37Conference paper (Refereed)
    Abstract [en]

    Embryo cultures of rodents is an established technique for monitoring adverse effects of chemicals on embryonic development. The assessment involves determination of the heart rate of the embryo which is usually done visually, a technique which is tedious and error prone. We present a new method for fully automatic heart detection in digital videos of rat embryos. First it detects the heart location, and then it counts the number of heart beats for a predetermined period of time. Using this automated method many more embryos can be evaluated at reasonable cost.

  • 383.
    Nilsson, Mats F.
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmaceutical Biosciences.
    Danielsson, C.
    Sköld, A.-C.
    Johansson, A.
    Blomgren, B.
    Wilson, J.
    Khan Niazi, Khalid Muhammad
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Bengtsson, Ewert
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Kultima, Kim
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmaceutical Biosciences. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences.
    Webster, W. S.
    Danielsson, Bengt R.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmaceutical Biosciences.
    Improved methodology for identifying the teratogenic potential in early drug development of hERG channel blocking drugs2010In: Reproductive Toxicology, ISSN 0890-6238, E-ISSN 1873-1708, Vol. 29, no 2, p. 156-163Article in journal (Refereed)
    Abstract [en]

    Drugs blocking the potassium current IKr of the heart (via hERG channel-inhibition) have the potential to cause hypoxia-related teratogenic effects. However, this activity may be missed in conventional teratology studies because repeat dosing may cause resorptions. The aim of the present study was to investigate an alternative protocol to reveal the teratogenic potential of IKr-blocking drugs. The IKr blocker astemizole, given as a single dose (80mg/kg) on gestation day (GD) 13 to pregnant rats caused digital defects. In whole rat embryo culture (2h) on GD 13, astemizole caused a decrease in embryonic heart rate at 20nM, and arrhythmias at 200-400nM. Cetirizine, without IKr-blocking properties, did not affect the rat embryonic heart in vitro. The present study shows that single dose testing on sensitive days of development, together with whole embryo culture, can be a useful methodology to better characterize the teratogenic potential of IKr-blocking drugs.

  • 384.
    Nilsson, Ola
    et al.
    Department of Science and Technology.
    Brun, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Distance maps in an arbitrary metric tensor field: An iterative solver for 2-D charts2008In: Proceedings of SSBA, Lund, Sweden: SSBA , 2008Conference paper (Other academic)
  • 385.
    Nisell, J.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Some Applications of Remote Sensing for Monitoring of Environment and Agriculture2000Licentiate thesis, monograph (Other scientific)
  • 386.
    Nordin, Bo
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Bengtsson, Ewert
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Dahlqvist, Bengt
    Eriksson, Olle
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Jarkrans, Torsten
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Stenkvist, Björn
    Object Oriented Cell Image Segmentation1982In: Proceedings of the IEEE International Symposium on Medical Imaging and Image Interpretation, 1982, p. 140-145Conference paper (Refereed)
  • 387.
    Norell, Kristin
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    An automatic method for counting annual rings in noisy sawmill images2009In: Image Analysis and Processing – ICIAP 2009, Springer Berlin / Heidelberg , 2009, p. 307-316Conference paper (Refereed)
    Abstract [en]

    The annual ring pattern of a log end face is related to the quality of the wood. We propose a method for computing the number of annual rings on a log end face depicted in sawmill production. The method is based on the grey-weighted polar distance transform and registration of detected rings from two different directions. The method is developed and evaluated on noisy images captured in on-line sawmill production at a Swedish sawmill during 2008, using an industrial colour camera. We have also evaluated the method using synthetic data with different ring widths, ring eccentricity, and noise levels.

  • 388.
    Norell, Kristin
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Creating synthetic log end face images2009In: Proceedings of 6th International Symposium on Image and Signal Processing and Analysis, 2009.: ISPA 2009. / [ed] P. Zinterhof; S. Loncaric; A. Uhl; A.Carini, 2009, p. 353-358Conference paper (Refereed)
    Abstract [en]

    In this paper we present the design and creation of synthetic images of log end faces. The images are constructed to resemble images of Scots pine taken in on-line sawmill production. Wood features such as knots, heartwood, and annual rings, as well as the sawing procedure, storage, and imaging, including camera position, are simulated. A dataset of 100 images is provided, together with code for generating new synthetic data.

  • 389.
    Norell, Kristin
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Finding the Pith in Rough Cross-Sections of Logs in Saw Mill Environments2006In: Proceedings SSBA 2006: Symposium in Image Analysis, 2006, p. 132-Conference paper (Other academic)
    Abstract [en]

    A method for automatic estimation of the location of the pith, i.e., the centre of the annual rings, in wood log end images is presented. The images used are images of untreated log ends in saw mill environments taken with a standard digital camera. The method consists of three major steps: calculating local orientation in each pixel to compute the normal directions of the annual rings, determining where in the image these normal directions intersect, and refining the result by scalar multiplication with a filter with the properties of a circular pattern.

  • 390.
    Norell, Kristin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Borgefors, Gunilla
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Estimation of pith position in untreated log ends in sawmill environments2008In: Computers and Electronics in Agriculture, ISSN 0168-1699, E-ISSN 1872-7107, Vol. 63, no 2, p. 155-167Article in journal (Refereed)
    Abstract [en]

    Two related methods for automatic estimation of the pith position, i.e., the centre of the annual rings, in wood log end face images are presented. We use images that depict untreated log end faces that are deliberately chosen to include difficulties such as rot, non-circular shape, uncentered pith and dirt. The images are taken with a regular digital camera in sawmill environments. Both presented methods use local orientation and Hough transform to detect the pith position, but two different ways to compute the local orientation are used. The results are promising for both methods. At least one of the methods is fast enough to use on-line at a sawmill.

  • 391.
    Norell, Kristin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Borgefors, Gunilla
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Årsringsmätning med bildanalys2010In: Fakta Skog, SLU, no 2, p. 4p-Article in journal (Other academic)
  • 392.
    Norell, Kristin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Lindblad, Joakim
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Spatially-variant morphological operations on binary images based on the polar distance transform2008In: ICPR 2008, IEEE computer society , 2008Conference paper (Refereed)
    Abstract [en]

    Binary mathematical morphology can be computed by thresholding a distance transform, provided that the distance transform is a metric. Here we show that the polar distance transform is a metric and use it for morphological operations. The polar distance transform varies with the spatial coordinates of the image, resulting in spatially-variant morphology. In this distance transform each pixel is related to an image origin. We prefer angular propagation over radial, thus we construct structuring elements that are elongated in the angular direction, which is useful when circular segments are handled. We show an example where segments of annual rings on a log end face are connected using mathematical morphology based on the polar distance transform.

  • 393.
    Norell, Kristin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Lindblad, Joakim
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Svensson, Stina
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Grey Weighted Polar Distance Transform for Outlining Circular and Approximately Circular Objects2007In: 14th International Conference on Image Analysis and Processing: ICIAP 2007, 2007, p. 647-652Conference paper (Refereed)
    Abstract [en]

    We introduce the polar distance transform and the grey weighted polar distance transform for computation of minimum cost paths preferring circular shape, as well as give algorithms for implementations in a digital setting. An alternative to the polar distance transform is to transform the image to polar coordinates, and then apply a Cartesian distance transform. By using the polar distance transform, re-sampling of the image and interpolation of new pixel values are avoided. We also handle the case of grey weighted distance transform in a $5\times 5$ neighbourhood, which, to our knowledge, is new. Initial results of using the grey weighted polar distance transform to outline annual rings in images of log end faces are presented.

  • 394.
    Norell, Kristin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Lindblad, Joakim
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Svensson, Stina
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    The polar distance transform2008In: Proceedings SSBA 2008, Symposium on image analysis, Lund, 2008Conference paper (Other academic)
    Abstract
  • 395.
    Norrman, John
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Lindell, Tommy
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    The Coast of the South-East Mediterrenian - El Alamein to Haifa1997In: Ymer Årsbok, The Swedish Society for Anthropology and Geography , 1997, p. 11-Chapter in book (Other (popular science, discussion, etc.))
  • 396. Nygård, Per
    et al.
    Gradin, Per
    Gregersen, Øyvind
    Lindblad, Joakim
    Axelsson, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Svensson, Stina
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Malmberg, Filip
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Borgefors, Gunilla
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Damage Mechanisms in Paper2006In: 2006 Progress in Paper Physics, 2006Conference paper (Other academic)
  • 397.
    Nystrom, I
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Smedby, O
    Skeletonization of volumetric vascular images - Distance information utilized for visualization2001In: JOURNAL OF COMBINATORIAL OPTIMIZATION, ISSN 1382-6905, Vol. 5, no 1, p. 27-41Article in journal (Refereed)
    Abstract [en]

    This paper deals with two techniques to represent relevant information from volumetric vascular images in a more compact format. The images are obtained with contrast-enhanced magnetic resonance angiography (MRA). After segmentation of the vessels, the cu

  • 398.
    Nyström, I.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Sanniti di Baja, G.
    Svensson, S.
    Curve Skeletonization by Junction Detection2001In: International Workshop on Visual Form (IWVF4), Capri, Italy, 2001, p. 229-238Conference paper (Refereed)
    Abstract [en]

    We present an algorithm that, starting from the surface skeleton of a 3D solid

  • 399.
    Nyström, I.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Sanniti di Baja, G.
    Svensson, S.
    Representing Volumetric Vascular Structures Using Curve Skeletons2001Conference paper (Refereed)
    Abstract [en]

    This paper describes a technique to represent relevant information of tree-like

  • 400.
    Nyström, I.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Smedby, Ö.
    Analysis of Magnetic Resonance Angiography Images Using Skeletonization and Distance Transforms2000Chapter in book (Refereed)
    Abstract [en]

    In magnetic resonance angiography (MRA), large 3D data sets of the vascular

567891011 351 - 400 of 683
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