SkiMap: An Efficient Mapping Framework for Robot Navigation

We present a novel mapping framework for robot navigation which features a multi-level querying system capable to obtain rapidly representations as diverse as a 3D voxel grid, a 2.5D height map and a 2D occupancy grid. These are inherently embedded into a memory and time efficient core data structure organized as a Tree of SkipLists. Compared to the well-known Octree representation, our approach exhibits a better time efficiency, thanks to its simple and highly parallelizable computational structure, and a similar memory footprint when mapping large workspaces. Peculiarly within the realm of mapping for robot navigation, our framework supports realtime erosion and re-integration of measurements upon reception of optimized poses from the sensor tracker, so as to improve continuously the accuracy of the map.Comment: Accepted by International Conference on Robotics and Automation (ICRA) 2017. This is the submitted version. The final published version may be slightly differen

Streaming visualisation of quantitative mass spectrometry data based on a novel raw signal decomposition method

As data rates rise, there is a danger that informatics for high-throughput LC-MS becomes more opaque and inaccessible to practitioners. It is therefore critical that efficient visualisation tools are available to facilitate quality control, verification, validation, interpretation, and sharing of raw MS data and the results of MS analyses. Currently, MS data is stored as contiguous spectra. Recall of individual spectra is quick but panoramas, zooming and panning across whole datasets necessitates processing/memory overheads impractical for interactive use. Moreover, visualisation is challenging if significant quantification data is missing due to data-dependent acquisition of MS/MS spectra. In order to tackle these issues, we leverage our seaMass technique for novel signal decomposition. LC-MS data is modelled as a 2D surface through selection of a sparse set of weighted B-spline basis functions from an over-complete dictionary. By ordering and spatially partitioning the weights with an R-tree data model, efficient streaming visualisations are achieved. In this paper, we describe the core MS1 visualisation engine and overlay of MS/MS annotations. This enables the mass spectrometrist to quickly inspect whole runs for ionisation/chromatographic issues, MS/MS precursors for coverage problems, or putative biomarkers for interferences, for example. The open-source software is available from http://seamass.net/viz/

Iterative transmission image reconstruction for the DPET positron emission tomograph

Positron emission tomography (PET) systems use transmission imaging to compensate for attenuation. One commercial example of this approach is the Siemens Inveon Dedicated PET (DPET), a 120mm bore system dedicated to the study of small animals. DPET transmission images are currently reconstructed using single slice rebinning followed by filtered backprojection. Single slice rebinning attributes the attenuation associated with an oblique line integral to the direct midplane intersected thereby. This leads to position-dependent axial blurring, especially for large diameter animals, and objects with abrupt axial changes in diameter. The mathematics underlying filtered backprojection are based on assumptions that are not met by the scanner, including but not limited to data being sampled in a uniform fashion. These limitations can be alleviated by an iterative algorithm if the associated system model is made to match the physical set-up. The downside is typically viewed as a potentially prohibitive increase in the computational cost. In this dissertation, we report on the implementation and use of Simultaneous Iterative Reconstruction Technique (SIRT) (a weighted least-squares solver) for transmission imaging on the DPET. We provide experimental evidence regarding the improvement in transmission image quality. We also show that these new, higher quality images can be computed in less than two minutes on the existing DPET host computer thus making the approach practical. Computational speed is gained both algorithmically through relaxation and use of ordered subsets and implementation-wise through vector based arithmetic and multi-core program execution

Reunion and reconciliation, reviewed and reconsidered

At the close of the Civil War in 1865, many Americans began talking about “reunion” and “reunification,” even “healing” and “reconciliation,” although the precise meaning of those words would remain elusive. From 1865 down to the present day, these sentiments have reverberated in American culture and American politics, and they sounded at gatherings of Union and Confederate veterans and then of their descendants, in the pages of newspapers and magazines in the late nineteenth and early twentieth centuries, in the speeches of presidents and politicians, and in countless films and theatrical productions that imagined northern and southern men joining hands in unity and fraternal love. Two years after the surrender at Appomattox, the former abolitionist Gerrit Smith told of his longing “for a heart-union between the North and the South.” Seventy-one years later, in a final gathering of ancient soldiers on the once-blood-soaked fields of Gettysburg, Franklin D. Roosevelt dedicated an Eternal Light Peace Memorial and honored the “joint and precious heritage” that Gettysburg had come to symbolize. Speaking in July 1938 to the “men who wore the blue and men who wore the gray,” fdr praised all the soldiers, “not asking under which flag they fought then—thankful that they stand together under one flag now.” Roosevelt’s tribute to a peace-loving and unified America, coming at this moment when the world was poised on the brink of an even more catastrophic war, may have offered its own small measure of comfort to anxious Americans.Accepted manuscrip

Mesh-based 3D Textured Urban Mapping

In the era of autonomous driving, urban mapping represents a core step to let vehicles interact with the urban context. Successful mapping algorithms have been proposed in the last decade building the map leveraging on data from a single sensor. The focus of the system presented in this paper is twofold: the joint estimation of a 3D map from lidar data and images, based on a 3D mesh, and its texturing. Indeed, even if most surveying vehicles for mapping are endowed by cameras and lidar, existing mapping algorithms usually rely on either images or lidar data; moreover both image-based and lidar-based systems often represent the map as a point cloud, while a continuous textured mesh representation would be useful for visualization and navigation purposes. In the proposed framework, we join the accuracy of the 3D lidar data, and the dense information and appearance carried by the images, in estimating a visibility consistent map upon the lidar measurements, and refining it photometrically through the acquired images. We evaluate the proposed framework against the KITTI dataset and we show the performance improvement with respect to two state of the art urban mapping algorithms, and two widely used surface reconstruction algorithms in Computer Graphics.Comment: accepted at iros 201

DIGITAL: multidisciplinary and multidimensional in the classrooms

In this paper our aim is to analyse and present some pedagogical paths that prefigure and guide the teaching-learning devices developed "around" the digital tools. In this context issues related to the implementation with teaching methodologies and teaching techniques acquire a new dimension due to the need of transpose them into online learning environments (technologies to teach to technologies to learn). This starting point is a deep understanding from the analysis of actors in the online learning process: student, teacher, platform and e- contents. Thus, it is our goal in this chapter to promote digital education, think of teaching methods, tools and learning processes, to adapted to eLearninginfo:eu-repo/semantics/publishedVersio