| 11. |
- Alvén, Jennifer, 1989, et al.
(författare)
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Shape-aware multi-atlas segmentation
- 2016
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Ingår i: Proceedings - International Conference on Pattern Recognition. - 1051-4651. ; 0, s. 1101-1106
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Konferensbidrag (refereegranskat)abstract
- Despite of having no explicit shape model, multi-atlas approaches to image segmentation have proved to be a top-performer for several diverse datasets and imaging modalities. In this paper, we show how one can directly incorporate shape regularization into the multi-atlas framework. Unlike traditional methods, our proposed approach does not rely on label fusion on the voxel level. Instead, each registered atlas is viewed as an estimate of the position of a shape model. We evaluate and compare our method on two public benchmarks: (i) the VISCERAL Grand Challenge on multi-organ segmentation of whole-body CT images and (ii) the Hammers brain atlas of MR images for segmenting the hippocampus and the amygdala. For this wide spectrum of both easy and hard segmentation tasks, our experimental quantitative results are on par or better than state-of-the-art. More importantly, we obtain qualitatively better segmentation boundaries, for instance, preserving fine structures.
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| 12. |
- Anistratov, Pavel, 1990, et al.
(författare)
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Dynamics-Based Optimal Motion Planning of Multiple Lane Changes using Segmentation
- 2022
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Ingår i: IFAC-PapersOnLine. - : Elsevier BV. - 2405-8963 .- 2405-8963. ; 55:24, s. 233-240
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Konferensbidrag (refereegranskat)abstract
- Avoidance maneuvers at normal driving speed or higher are demanding driving situations that force the vehicle to the limit of tire-road friction in critical situations. To study and develop control for these situations, dynamic optimization has been in growing use in research. One idea to handle such optimization computations effectively is to divide the total maneuver into a sequence of sub-maneuvers and to associate a segmented optimization problem to each sub-maneuver. Here, the alternating augmented Lagrangian method is adopted, which like many other optimization methods benefits strongly from a good initialization, and to that purpose a method with motion candidates is proposed to get an initially feasible motion. The two main contributions are, firstly, the method for computing an initially feasible motion that is found to use obstacle positions and progress of vehicle variables to its advantage, and secondly, the integration with a subsequent step with segmented optimization showing clear improvements in paths and trajectories. Overall, the combined method is able to handle driving scenarios at demanding speeds.
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| 13. |
- Ask, Erik, et al.
(författare)
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Tractable and Reliable Registration of 2D Point Sets
- 2014
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Ingår i: Lecture Notes in Computer Science (Computer Vision - ECCV 2014, 13th European Conference, Zurich, Switzerland, September 6-12, 2014, Proceedings, Part I). - Cham : Springer International Publishing. - 0302-9743 .- 1611-3349. - 9783319105895 - 9783319105901 ; 8689, s. 393-406
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Konferensbidrag (refereegranskat)abstract
- This paper introduces two new methods of registering 2D point sets over rigid transformations when the registration error is based on a robust loss function. In contrast to previous work, our methods are guaranteed to compute the optimal transformation, and at the same time, the worst-case running times are bounded by a low-degree polynomial in the number of correspondences. In practical terms, this means that there is no need to resort to ad-hoc procedures such as random sampling or local descent methods that cannot guarantee the quality of their solutions. We have tested the methods in several different settings, in particular, a thorough evaluation on two benchmarks of microscopic images used for histologic analysis of prostate cancer has been performed. Compared to the state-of-the-art, our results show that the methods are both tractable and reliable despite the presence of a significant amount of outliers.
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| 14. |
- Askerdal, Örjan, 1973, et al.
(författare)
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A Control Theory Approach for Analyzing the Effects of Data Errors in Safety-Critical Control Systems
- 2002
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Ingår i: Pacific Rim International Symposium on Dependable Computing, 2002. Proceedings. 2002. - 0769518524 ; , s. 105-114
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Konferensbidrag (refereegranskat)abstract
- Computers are increasingly used for implementing controlalgorithms in safety-critical embedded applications, such asengine control, braking control and flight surfacecontrol. Addressing the consequent coupling of control performancewith computer related errors, this paper develops a composite computerdependability/control theory methodology for analyzing the effectsdata errors have on control system dependability. The effect is measured as theresulting control error (defined as the difference between the desired value ofa physical property andits actual value). We use maximum bounds on this measure as the criterion forcontrol system failure (i.e., if the control error exceeds a certain threshold,the system has failed).In this paper we a) present suitable models of computer faults for analysis of control level effects andrelated analysis methods, and b) apply traditional control theoryanalysis methods for understanding the effects of data errors onsystem dependability. An automobile slip-control brake-system is used as an example showing the viability of our approach.
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| 15. |
- Assarsson, Ulf, 1972, et al.
(författare)
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A Geometry-based Soft Shadow Volume Algorithm using Graphics Hardware
- 2003
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Ingår i: ACM Transactions on Graphics. - : Association for Computing Machinery (ACM). - 1557-7368 .- 0730-0301. ; 22:3, s. 511-520
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Konferensbidrag (refereegranskat)abstract
- Most previous soft shadow algorithms have either suffered from aliasing, been too slow, or could only use a limited set of shadow casters and/or receivers. Therefore, we present a strengthened soft shadow volume algorithm that deals with these problems. Our critical improvements include robust penumbra wedge construction, geometry-based visibility computation, and also simplified computation through a four-dimensional texture lookup. This enables us to implement the algorithm using programmable graphics hardware, and it results in images that most often are indistinguishable from images created as the average of 1024 hard shadow images. Furthermore, our algorithm can use both arbitrary shadow casters and receivers. Also, one version of our algorithm completely avoids sampling artifacts which is rare for soft shadow algorithms. As a bonus, the four-dimensional texture lookup allows for small textured light sources, and, even video textures can be used as light sources. Our algorithm has been implemented in pure software, and also using the GeForce FX emulator with pixel shaders. Our software implementation renders soft shadows at 0.5-5 frames per second for the images in this paper. With actual hardware, we expect that our algorithm will render soft shadows in real time. An important performance measure is bandwidth usage. For the same image quality, an algorithm using the accumulated hard shadow images uses almost two orders of magnitude more bandwidth than our algorithm.
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| 16. |
- Avdovic, Pajazit, 1955, et al.
(författare)
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Evaluating the machinability of Inconel 718 using polar diagrams
- 2010
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Ingår i: Proceedings of the ASME Turbo Expo 2010: Power for Land, Sea, and Air, GT 2010, Glasgow, United Kingdom, 14-18 June 2010. - 9780791843963 ; , s. 987-996
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Konferensbidrag (refereegranskat)abstract
- The use of a polar diagram method for describing and evaluating the machinability of Inconel 718 was explored. Five key parameters of the work material, representing the mechanical and physical properties which have strongest influence on its machinability, were employed in the diagrams. These five parameters were integrated into a single polar diagram, used to describe the machinability of Inconel 718. Variations in the machinability of Inconel 718 products or components of a given type produced in different batches were analyzed. Industrial experiments were conducted to test the relationship between the polar diagram of the work material, its carbon content, and tool wear of the ceramic cutting tools used in machining it. Work materials of Inconel 718 in which the polar diagrams of machinability were similar in size and shape exhibited very similar behavior during the cutting process. The polar diagram method employed appeared to be useful for selecting suitable cutting data for the machining of new materials.
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| 17. |
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| 18. |
- Bardizbanyan, Alen, 1986, et al.
(författare)
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Logic Filter Cache for Wide-VDD-Range Processors
- 2016
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Ingår i: Proceedings of 23rd IEEE Int. Conf. on Electronics, Circuits and Systems. - 9781509061136 ; , s. 376-379
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Konferensbidrag (refereegranskat)abstract
- Wide-VDD-range processors offer high energy efficiency for varying embedded workloads. But reducing the VDD of the cache as aggressively as the VDD of the CPU logic is not straightforward, since standard 6T SRAMs cease to operate at lower VDDs. We implement a data and instruction filter cache, using logic cells located in the CPU VDD domain, to permit the level-1 (L1) cache to be reliably powered at a higher SRAM VDD. On top of eliminating many energy-wasting L1 cache accesses, the filter cache reduces the total number of executed cycles. Furthermore, the filter cache can be reconfigured as CPU VDD is reduced, to filter out an increasing proportion of cache accesses. We evaluate our approach using a 65-nm 1.2-V low-leakage CMOS process, with a minimal CPU and SRAM VDD of 0.4 and 0.95V, respectively. Assuming 16kB+16kB L1 caches and 256B+256B filter caches, introducing the filter cache reduces the total cache access energy by 71% at 1.2V and 87% at 0.4V at an area overhead which is 13% of the L1 cache area.
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| 19. |
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| 20. |
- Beech, J. P., et al.
(författare)
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What do photons do to fluorescently stained DNA in confinement?
- 2013
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Ingår i: 17th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2013; Freiburg; Germany; 27 October 2013 through 31 October 2013. ; 1, s. 5-7
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Konferensbidrag (refereegranskat)abstract
- We have studied a selection of factors influencing the damage of DNA in nanochannels during fluorescence imaging. For cutting and nicking of DNA we show that the DNA is shortened during imaging. To avoid photodamage over the course of several hours of a typical experiment, we demonstrate the importance of an oxygen free gas to propel the buffer solution through the device. Finally, by varying the size of the channels, we show indications that higher DNA concentrations lead to higher rates of photodamage necessitating a balance between needs for highly stretched DNA and needs for long measurement times.
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