| 31. |
- Larsson, Johan, et al.
(författare)
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Fast laser-based feature recognition
- 2005
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Konferensbidrag (refereegranskat)abstract
- This paper we present our methods for feature recognition used for high speed reactive navigation based on a topological map, with none or sparse metric information. Our methods for corridor and intersection detection yields execution times of only a fraction of what we have found previously described in the relevant literature, and have proven robust and reliable in experiments performed both in office environment and in our test mine [Larsson et al., 2005]. A. Related Work Our Corridor
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| 32. |
- Larsson, Johan, et al.
(författare)
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Flexible infrastructure free navigation for vehicles in underground mines
- 2008
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Ingår i: 4th international IEEE conference intelligent systems, IS '08. - New York : IEEE. - 9781424417391 ; , s. 2-45-2-50
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Konferensbidrag (refereegranskat)abstract
- During the last decade, mining companies and mobile equipment manufacturers have pursued improved efficiency, productivity, and safety in underground mining operations by automating some of the functions of underground vehicles. The work presented in this paper is the result of an effort to develop new flexible infrastructureless guidance system for autonomous tramming of center-articulated underground mining vehicles.
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| 33. |
- Larsson, Johan, et al.
(författare)
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Laser-based corridor detection for reactive navigation
- 2008
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Ingår i: Industrial robot. - : Emerald. - 0143-991X .- 1758-5791. ; 35:1, s. 69-79
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Tidskriftsartikel (refereegranskat)abstract
- For mobile robots operating in real-world environments, reactive navigation is a useful complement (or even replacement) to pure plan-based metric navigation. Reactive navigation is performed with respect to local perceived features, rather than a global metric reference frame, and can provide reduced installation costs, increased flexibility, and robustness to changes in the environment. To be effective, however, reactive navigation requires fast and reliable perception of the relevant features in the environment. Corridor-like structures are one of the most common features that are used for this purpose. In this paper, we propose a new method for corridor detection from laser data, based on the Hough transform, which is fast, reliable, and noise tolerant. We describe the algorithm, report an extensive experimental evaluation of its performance, and motivate the research with a real application involving the autonomous operation of a loader vehicle in an underground mine.
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| 34. |
- Larsson, Johan, et al.
(författare)
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Laser based intersection detection for reactive navigation in an underground mine
- 2008
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Ingår i: IEEE/RSJ international conference on intelligent robots and systems, 2008, IROS 2008. - 9781424420575 ; , s. 2222-2227
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Konferensbidrag (refereegranskat)abstract
- In this paper we propose a new feature detection algorithm to enable junction recognition intended for high speed reactive navigation in tunnel like environments. We also present an extensive experimental evaluation of the algorithm based on data recorded in a real mine. The algorithm is faster and has less environmental constraints than similar algorithms that can be found in the litterature.
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| 35. |
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| 36. |
- Lidén, Mats, 1976-, et al.
(författare)
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Two- and three-dimensional CT measurements of urinary calculi length and width : a comparative study
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The standard imaging procedure for a patient presenting with renal colic is unenhanced CT. The CT measured size has a close correlation to the estimated prognosis for spontaneous passage of a ureteral calculus. Size estimations of urinary calculi in CT images are still based on 2d-reformats. In the present study we developed and validated a calculus oriented 3dmethod for measurements of length and width of urinary calculi and compared those with corresponding 2d measurements in axial and coronal reformats.Methods: Fifty unenhanced CT examinations demonstrating urinary calculi were included. A 3d-symmetric segmentation algorithm was validated against reader size estimations. The calculus-oriented size from the segmentation was then compared to the size in axial and coronal reformats.Results: The validation showed 0.1±0.7 mm agreement against reference measure. There was a 0.4 mm median bias for 3d-estimated calculus length compared to 2d (p<0.001), but no significant bias for 3d-width compared to 2d.Conclusion: The size of the urinary calculus becomes underestimated if its orientation is not aligned to the axial or coronal image plane. Future studies aiming to correlate calculus size with patient outcome should use a calculus oriented size estimation.
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| 37. |
- Lidén, Mats, 1976-, et al.
(författare)
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Urinary stone size estimation : a new segmentation algorithm-based CT method
- 2012
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Ingår i: European Radiology. - New York, USA : Springer. - 0938-7994 .- 1432-1084. ; 22:4, s. 731-737
-
Tidskriftsartikel (refereegranskat)abstract
- The size estimation in CT images of an obstructing ureteral calculus is important for the clinical management of a patient presenting with renal colic. The objective of the present study was to develop a reader independent urinary calculus segmentation algorithm using well-known digital image processing steps and to validate the method against size estimations by several readers. Fifty clinical CT examinations demonstrating urinary calculi were included. Each calculus was measured independently by 11 readers. The mean value of their size estimations was used as validation data for each calculus. The segmentation algorithm consisted of interpolated zoom, binary thresholding and morphological operations. Ten examinations were used for algorithm optimisation and 40 for validation. Based on the optimisation results three segmentation method candidates were identified. Between the primary segmentation algorithm using cubic spline interpolation and the mean estimation by 11 readers, the bias was 0.0 mm, the standard deviation of the difference 0.26 mm and the Bland-Altman limits of agreement 0.0 +/- 0.5 mm. The validation showed good agreement between the suggested algorithm and the mean estimation by a large number of readers. The limit of agreement was narrower than the inter-reader limit of agreement previously reported for the same data. The size of kidney stones is usually estimated manually by the radiologist. An algorithm for computer-aided size estimation is introduced. The variability between readers can be reduced. A reduced variability can give better information for treatment decisions.
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| 38. |
- Loutfi, Amy, et al.
(författare)
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Object recognition : a new application for smelling robots
- 2005
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Ingår i: Robotics and Autonomous Systems. - : Elsevier BV. - 0921-8890 .- 1872-793X. ; 52:4, s. 272-289
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Tidskriftsartikel (refereegranskat)abstract
- Olfaction is a challenging new sensing modality for intelligent systems. With the emergence of electronic noses, it is now possible to detect and recognize a range of different odours for a variety of applications. In this work, we introduce a new application where electronic olfaction is used in cooperation with other types of sensors on a mobile robot in order to acquire the odour property of objects.We examine the problem of deciding when, how and where the electronic nose (e-nose) should be activated by planning for active perception and we consider the problem of integrating the information provided by the e-nose with both prior information and information from other sensors (e.g., vision). Experiments performed on a mobile robot equipped with an e-nose are presented.
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| 39. |
- Loutfi, Amy, et al.
(författare)
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Putting olfaction into action : using an electronic nose on an multi-sensing mobile robot
- 2004
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Ingår i: Proceedings of the 2004 IEEE/RSJ international conference on intelligent robots and systems (IROS 2004). - 0780384636 ; , s. 337-342
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Konferensbidrag (refereegranskat)abstract
- Olfaction is a challenging new sensing modality for intelligent systems. With the emergence of electronic noses it is now possible to detect and recognise a range of different odours for a variety of applications. An existing application is to use electronic olfaction on mobile robots for the purpose of odour based navigation. In this work, we introduce a new application where electronic olfaction is used in cooperation with other types of sensors on a mobile robot in order to acquire the odour
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| 40. |
- Loutfi, Amy, et al.
(författare)
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Putting olfaction into action : anchoring symbols to sensor data using olfaction and planning
- 2005
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Ingår i: Workshop on planning and learning in a priori unknown or dynamic domains. ; , s. 35-40
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Konferensbidrag (refereegranskat)abstract
- Olfaction is a challenging new sensing modality for intelligent systems. With the emergence of electronic noses (e-noses) it is now possible to train a system to detect and recognise a range of different odours. In this work, we integrate the electronic nose on a multi-sensing mobile robotic platform. We plan for perceptual actions and examine when, how and where the e-nose should be activated.Finally, experiments are performed on a mobile robot equipped with an e-nose together with a variety of sensors and used for object detection.
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