You are here! Finding position and orientation on a 2D map from a single image: The Flatlandia localization problem and dataset

We introduce Flatlandia, a novel problem for visual localization of an image from object detections composed of two specific tasks: i) Coarse Map Localization: localizing a single image observing a set of objects in respect to a 2D map of object landmarks; ii) Fine-grained 3DoF Localization: estimating latitude, longitude, and orientation of the image within a 2D map. Solutions for these new tasks exploit the wide availability of open urban maps annotated with GPS locations of common objects (\eg via surveying or crowd-sourced). Such maps are also more storage-friendly than standard large-scale 3D models often used in visual localization while additionally being privacy-preserving. As existing datasets are unsuited for the proposed problem, we provide the Flatlandia dataset, designed for 3DoF visual localization in multiple urban settings and based on crowd-sourced data from five European cities. We use the Flatlandia dataset to validate the complexity of the proposed tasks

Rethinking Pose in 3D: Multi-stage Refinement and Recovery for Markerless Motion Capture

We propose a CNN-based approach for multi-camera markerless motion capture of the human body. Unlike existing methods that first perform pose estimation on individual cameras and generate 3D models as post-processing, our approach makes use of 3D reasoning throughout a multi-stage approach. This novelty allows us to use provisional 3D models of human pose to rethink where the joints should be located in the image and to recover from past mistakes. Our principled refinement of 3D human poses lets us make use of image cues, even from images where we previously misdetected joints, to refine our estimates as part of an end-to-end approach. Finally, we demonstrate how the high-quality output of our multi-camera setup can be used as an additional training source to improve the accuracy of existing single camera models.Comment: International Conference on 3DVision (3dv

Timber-concrete composite bridges: Three case studies

During the last years, timber-concrete composite (TCC) structures have been extensively used in Europe both in new and existing buildings. Generally speaking, a composite structure combines the advantages of both materials employed: the strength and stiffness of the concrete in compression and the tensile strength, lightweight, low embodied energy, and aesthetical appearance of the timber. The concrete slab provides protection of the timber beams from direct contact with water, which is crucial to ensure the durability of the timber beams, particularly when used for bridges. Different types of connectors can be used to provide force exchange between the concrete slab and the timber beam. The choice of a structurally effective yet cheap shear connection between the concrete topping and the timber joist is crucial to make the TCC structures a viable solution that can compete with reinforced concrete and steel structures. In this paper, the possibilities offered by TCC structures for short-span bridge decks are discussed. The technology of TCC structures and the general design rules are illustrated. Three case studies are reported, including a short-span bridge tested in Colorado, USA, with the timber layer being constructed from recycled utility poles and notch connection; a TCC bridge with glulam beams and triangular notches with epoxy-glued rebar connectors built in Portugal; and a TCC bridge with glulam beams and rectangular notches built in Germany. All the solutions were found to be structurally effective and aesthetically pleasing. They can all provide a sustainable option for short-span bridges. Keywords: Timber-concrete composite, Bridge, Design, Connection syste

Grid Cells Lose Coherence in Realistic Environments

Spatial cognition in naturalistic environments, for freely moving animals, may pose quite different constraints from that studied in artificial laboratory settings. Hippocampal place cells indeed look quite different, but almost nothing is known about entorhinal cortex grid cells, in the wild. Simulating our self-organizing adaptation model of grid cell pattern formation, we consider a virtual rat randomly exploring a virtual burrow, with feedforward connectivity from place to grid units and recurrent connectivity between grid units. The virtual burrow was based on those observed by John B. Calhoun, including several chambers and tunnels. Our results indicate that lateral connectivity between grid units may enhance their “gridness” within a limited strength range, but the overall effect of the irregular geometry is to disable long-range and obstruct short-range order. What appears as a smooth continuous attractor in a flat box, kept rigid by recurrent connections, turns into an incoherent motley of unit clusters, flexible or outright unstable

OUTCOMES OF ELDERLY PATIENTS WITH ST-ELEVATION OR NON-ST-ELEVATION ACUTE CORONARY SYNDROME UNDERGOING PERCUTANEOUS CORONARY INTERVENTION

Acute coronary syndromes have been classified according to the finding of ST-segment elevation on the presenting ECG, with different treatment strategies and practice guidelines. However, a comparative description of the clinical characteristics and outcomes of acute coronary syndrome elderly patients undergoing percutaneous coronary intervention during index admission has not been published so far