| 1. |
- Kaijser, Thomas
(författare)
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On the Computation of the Kantorovich Distance for Images
- 1996
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The Kantorovich distance for images can be defined for grey valued images with equal total grey value. Computing the Kantorovich distance is equivalent to solving a large transportation problem. The cost-function of this transportation problem depends on which distance-function one uses to measure distances between pixels.In this paper we present an algorithm, which is roughly of the order in case the underlying distance-function is l) the L1 – metric, 2) an approximation of the L2 – metric or 3) the square of the L2 – metric, where N is equal to the number of pixels in the two images. The algorithm is based on the classical primal-dual algorithm.The algorithm also gives rise to a transportation plan from one image to the other and we also show how this transportation plan can be used for interpolation and possibly also for compression and discrimination.
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| 2. |
- Falkeborn, Rikard, 1982-, et al.
(författare)
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A Decomposition Algorithm for KYP-SDPs
- 2009
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Ingår i: Proceedings of the 10th European Control Conference (ECC). - Linköping : Linköping University Electronic Press. - 9783952417393 ; , s. 3202-3207
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Konferensbidrag (refereegranskat)abstract
- In this paper, a structure exploiting algorithm for semidefinite programs derived from the Kalman-Yakubovich-Popov lemma, where some of the constraints appear as complicating constraints is presented. A decomposition algorithm is proposed, where the structure of the problem can be utilized. In a numerical example, where a controller that minimizes the sum of the H2-norm and the H∞-norm is designed, the algorithm is shown to be faster than SeDuMi and the special purpose solver KYPD.
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| 3. |
- Gerdin, Markus, et al.
(författare)
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Identification of a Nonlinear Cell Cycle System with Linear Models
- 2005
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Ingår i: Proceedings of the Conference on Modeling and Simulation in Biology, Medicine and Biomedical EngineeringMay 26-27, 2005, Linköping, Sweden. - Linköping : Linköping University Electronic Press. ; , s. 129-138
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A mathematical model by Chen et al. representing the cell cycle of the budding yeast cell (Saccharomyces cerevisiae) is used to simulate levels of 13 different cell biological variables. By using a linear systems approach on the generated data the goal is to identify the original equations of the mathematical model. Since this model is described by a nonlinear system the linear systems approach only gives correct estimations of the linear parts of the system, with one exception. A main issue thus becomes to identify which data that belongs to the linear equations and which does not. This problem is solved using two local linear models on different time intervals. Parameter estimations of coefficients from linear and time invariant equations should be the same over all time intervals.
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| 4. |
- Kang, Jeongmin, 1987-, et al.
(författare)
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State-of-the-art Report of Research about Multi Sensor Image-based Navigation
- 2023
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Rapport (populärvet., debatt m.m.)abstract
- This report aims to describe the latest research and method developmentof image-based multi sensor fusion navigation and summarizes open aerialdatasets which can support the latest research related to this project. Itsupports the initial setting of the direction of the algorithm development inthe early stage of the project.The Multi Sensor Image-based Navigation project aims to study and developthe methods focusing on image-based multisensor navigation in orderto acquire a precise localization of the aircraft. GNSS-based localizationand navigation systems are sensitive to disturbances and jamming, hencethe capability to provide reliable position accuracy without GNSS is a keyelement to develop the navigation systems.The output of this project can be utilized in a wide range of applications,such as aircraft operation in GNSS denied environments or urban air mobilitycontext.
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| 5. |
- Larsson, Fredrik, 1980-
(författare)
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Automatic 3D Model Construction for Turn-Table Sequences - A Simplification
- 2011
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report introduces some simplications to the method by Fitzgibbon et al. that allows for 3D model construction from turn-table sequences. It is assumed that the reader has previously read in order to fully understand this report.Fitzgibbon et al. presents a method for 3D model construction that utilizes the extra constraints imposed by turn-table sequences. Restricting the scenario to a turn-table sequence with a single camera with xed settings produces these extra constraints:C1. The internal parameters for the camera are the same for all imagesC2. The motion of the camera can be described by a rotation around a singleaxisIt is shown that in the uncalibrated case the number of parameters to estimate is m + 8 where m is the number of images.We further simplify the problem by using extra constrains given from the fact that we know:C3. The internal parameters of the camera, i.e the K matrixC4. That the angle between each pair of consecutive cameras is the sameUsing these extra simplications makes it possible to create a 3D model from realistic data without using Bundle Adjustment.
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| 6. |
- Nordberg, Klas, 1963-, et al.
(författare)
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A local geometry based descriptor for 3D data : Addendum on rank and segment extraction
- 2010
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This document is an addendum to the main text in A local geometry-based descriptor for 3D data applied to object pose estimation by Fredrik Viksten and Klas Nordberg. This addendum gives proofs for propositions stated in the main document. This addendum also details how to extract information from the fourth order tensor refered to as S22 in the main document.
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| 7. |
- Ohlsson, Henrik, 1981-, et al.
(författare)
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Direct Weight Optimization Applied to Discontinuous Functions
- 2008
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Ingår i: 47th IEEE Conference on Decision and Control, 2008. CDC 2008. - Cancun, Mexico : IEEE. - 9781424431236 ; , s. 117-122
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Konferensbidrag (refereegranskat)abstract
- The Direct Weight Optimization (DWO) approach is a nonparametric estimation approach that has appeared in recent years within the field of nonlinear system identification. In previous work, all function classes for which DWO has been studied have included only continuous functions. However, in many applications it would be desirable also to be able to handle discontinuous functions. Inspired by the bilateral filter method from image processing, such an extension of the DWO framework is proposed for the smoothing problem. Examples show that the properties of the new approach regarding the handling of discontinuities are similar to the bilateral filter, while at the same time DWO offers a greater flexibility with respect to different function classes handled.
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| 8. |
- Ohlsson, Henrik, 1981-, et al.
(författare)
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Enabling Bio-Feedback using Real-Time fMRI
- 2008
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Ingår i: 47th IEEE Conference on Decision and Control, 2008, CDC 2008. - Linköping : IEEE. - 9781424431236 ; , s. 3336-3341
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Konferensbidrag (refereegranskat)abstract
- Despite the enormous complexity of the human mind, fMRI techniques are able to partially observe the state of a brain in action. In this paper we describe an experimental setup for real-time fMRI in a bio-feedback loop. One of the main challenges in the project is to reach a detection speed, accuracy and spatial resolution necessary to attain sufficient bandwidth of communication to close the bio-feedback loop. To this end we have banked on our previous work on real-time filtering for fMRI and system identification, which has been tailored for use in the experiment setup. In the experiments presented the system is trained to estimate where a person in the MRI scanner is looking from signals derived from the visual cortex only. We have been able to demonstrate that the user can induce an action and perform simple tasks with her mind sensed using real-time fMRI. The technique may have several clinical applications, for instance to allow paralyzed and "locked in" people to communicate with the outside world. In the meanwhile, the need for improved fMRI performance and brain state detection poses a challenge to the signal processing community. We also expect that the setup will serve as an invaluable tool for neuro science research in general.
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| 9. |
- Papageorgiou, Christos, et al.
(författare)
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Formulation of the Stability Margins Clearance Criterion As a Convex Optimization Problem
- 2009
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Ingår i: Proceedings of the 6th IFAC Symposium on Robust Control Design. - Linköping : Linköping University Electronic Press. - 9783902661456 ; , s. 325-330
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Konferensbidrag (refereegranskat)abstract
- This paper presents the formulation of a flight clearance criterion as a convex optimization problem. The criterion is the stability margins criterion which is specified as an allowable phase and gain margin of a certain loop transfer function. The satisfaction of the criterion amounts to the Nichols plot of the loop transfer function being outside a specified trapezoidal region. It was shown previously that the exclusion condition from an ellipsoidal region is implied by using the generalized stability margin bPC and its calculation was performed frequency-wise by solving a sequence of convex optimization problems. In this paper we formulate the calculation of a lower bound on bPC as a convex optimization problem using Integral Quadratic Constraints (IQCs) and avoid the gridding procedure in the frequency domain. Furthermore, we formulate the problem of obtaining a lower bound on the perturbed stability margin, which is defined as the worst-case bPC over variations in real uncertain parameters.
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| 10. |
- Viksten, Fredrik, 1976-, et al.
(författare)
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Maximally Robust Range Regions
- 2010
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In this work we present a region detector, an adaptation to range data of the popular Maximally Stable Extremal Regions (MSER) region detector. We call this new detector Maximally Robust Range Regions (MRRR). We apply the new detector to real range data captured by a commercially available laser range camera. Using this data we evaluate the repeatability of the new detector and compare it to some other recently published detectors. The presented detector shows a repeatability which is better or the same as the best of the other detectors. The MRRR detector also offers additional data on the detected regions. The additional data could be crucial in applications such as registration or recognition.
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