Pictures in Your Mind: Using Interactive Gesture-Controlled Reliefs to Explore Art

Tactile reliefs offer many benefits over the more classic raised line drawings or tactile diagrams, as depth, 3D shape, and surface textures are directly perceivable. Although often created for blind and visually impaired (BVI) people, a wider range of people may benefit from such multimodal material. However, some reliefs are still difficult to understand without proper guidance or accompanying verbal descriptions, hindering autonomous exploration. In this work, we present a gesture-controlled interactive audio guide (IAG) based on recent low-cost depth cameras that can be operated directly with the hands on relief surfaces during tactile exploration. The interactively explorable, location-dependent verbal and captioned descriptions promise rapid tactile accessibility to 2.5D spatial information in a home or education setting, to online resources, or as a kiosk installation at public places. We present a working prototype, discuss design decisions, and present the results of two evaluation studies: the first with 13 BVI test users and the second follow-up study with 14 test users across a wide range of people with differences and difficulties associated with perception, memory, cognition, and communication. The participant-led research method of this latter study prompted new, significant and innovative developments

Feature-assisted interactive geometry reconstruction in 3D point clouds using incremental region growing

Reconstructing geometric shapes from point clouds is a common task that is often accomplished by experts manually modeling geometries in CAD-capable software. State-of-the-art workflows based on fully automatic geometry extraction are limited by point cloud density and memory constraints, and require pre- and post-processing by the user. In this work, we present a framework for interactive, user-driven, feature-assisted geometry reconstruction from arbitrarily sized point clouds. Based on seeded region-growing point cloud segmentation, the user interactively extracts planar pieces of geometry and utilizes contextual suggestions to point out plane surfaces, normal and tangential directions, and edges and corners. We implement a set of feature-assisted tools for high-precision modeling tasks in architecture and urban surveying scenarios, enabling instant-feedback interactive point cloud manipulation on large-scale data collected from real-world building interiors and facades. We evaluate our results through systematic measurement of the reconstruction accuracy, and interviews with domain experts who deploy our framework in a commercial setting and give both structured and subjective feedback.Comment: 13 pages, submitted to Computers & Graphics Journa

An interleukin-1 polymorphism additionally intensified by atopy as prognostic factor for aseptic non-mechanical complications in metal knee and hip arthroplasty

Background: In contrast to infection or mechanical issues joint replacement failure following inflammatory adverse reactions is poorly understood. Objective: To assess the association of IL-1β polymorphisms and history of allergy with aseptic non-mechanical complications following arthroplasty. Methods: In 102 patients with aseptic non-mechanically caused symptomatic knee or hip arthroplasty (SA) and 93 patients with asymptomatic arthroplasty (AA) questionnaire-based history, patch test with at least standard series, lymphocyte transformation test (LTT) with nickel, cobalt and chromium and interleukin-1 polymorphism analysis were done. Three polymorphisms of the IL1B gene [IL-1b -3954 (rs1143634), IL-1b -511 (rs16944) and IL-1b -31 (rs1143627)] and one polymorphism of the IL1RN gene [IL1RN intron 2, variable number of tandem repeats, VNTR (rs2234663)] were assessed by PCR and gel electrophoresis. Results: We found no significant difference in smoking history and atopy but 25% versus 10% of self-reported metal allergy in SA versus AA; the patch test (respective, LTT) for metal sensitivity was more often positive in SA patients. The allele 498 bp of the IL1RN polymorphism occurred significantly more often in the SA group (37% versus 11%; p < 0.0001). Upon additional presence of atopy, the difference was even greater (60% vs 10%) (p < 0.000001). There was no association of IL-1 polymorphisms with metal allergy. Conclusion: The IL1RN VNTR allele 498 bp was strongly associated with SA. In patients with a history of atopy, presence of the IL1RN VNTR allele 498 bp led to a four-fold higher SA prevalence compared to patients without this allele

Improved Illumination Estimation for Photon Maps in Architectural Scenes

The photon map algorithm provides a number of advantages for fast global illumination algorithms. In order to calculate the illumination at each point in a scene, the photon density needs to be estimated. Standard estimation methods will have problems with typical architectural scenes, as walls and corners will lead to undesirable light and shadow leaks. We introduce a new method for estimating photon density in photon maps, that is especially suited for calculating global illumination in architectural scenes. By providing additional information using a limited number of ray-casts, shadow and light leaks can be significantly reduced, thereby resulting in a significant improvement in the speed and accuracy of global illumination algorithms based on photon maps

A Mesh Data Structure for Rendering and Subdivision

Generating subdivision surfaces from polygonal meshes requires the complete topological information of the original mesh, in order to find the neighbouring faces, and vertices used in the subdivision computations. Normally, winged-edge type data-structures are used to maintain such information about a mesh. For rendering meshes, most of the topological information is irrelevant, and winged-edge type data-structures are inefficient due to their extensive use of dynamical data structures. A standard approach is the extraction of a rendering mesh from the winged-edge type data structure, thereby increasing the memory footprint significantly. We introduce a mesh data-structure that is efficient for both tasks: creating subdivision surfaces as well as fast rendering. The new data structure maintains full topological information in an efficient and easily accessible manner, with all information necessary for rendering optimally suited for current graphics hardware. This is possible by disallowing modifications of the mesh, once the topological information has been created. In order to avoid any inconveniences due to this limitation, we provide an API that makes it possible to stitch multiple meshes and access the topology of the resulting combined mesh as if it were a single mesh. This API makes the new mesh data structure also ideally suited for generating complex geometry using mesh-based L-systems