Algorithmic Perception of Vertices in Sketched Drawings of Polyhedral Shapes

In this article, visual perception principles were used to build an artificial perception model aimed at developing an algorithm for detecting junctions in line drawings of polyhedral objects that are vectorized from hand-drawn sketches. The detection is performed in two dimensions (2D), before any 3D model is available and minimal information about the shape depicted by the sketch is used. The goal of this approach is to not only detect junctions in careful sketches created by skilled engineers and designers but also detect junctions when skilled people draw casually to quickly convey rough ideas. Current approaches for extracting junctions from digital images are mostly incomplete, as they simply merge endpoints that are near each other, thus ignoring the fact that different vertices may be represented by different (but close) junctions and that the endpoints of lines that depict edges that share a common vertex may not necessarily be close to each other, particularly in quickly sketched drawings. We describe and validate a new algorithm that uses these perceptual findings to merge tips of line segments into 2D junctions that are assumed to depict 3D vertices

Comments on "what the back of the object looks like: 3D reconstruction from line drawings without hidden lines"

I comment on a paper describing a method for deducing the hidden topology of an object portrayed in a 2D natural line drawing. The principal problem with this paper is that it cannot be considered an advance on (or even an equal of) the state of the art as the approach it describes makes the same limiting assumptions as approaches proposed 10 years ago. There are also important omissions in the review of related wor

A method for reconstructing sketched polyhedral shapes with rounds and fillets

In this paper we present a method for detecting rounds and fillets in engineering sketches and drawings, and automatically generating a 3D model of the corresponding object, with rounds and fillets applied. This method is useful both as a component of computer-aided sketching tools and in determining de- sign intent—although rounds and fillets are common in engineering parts, they often conceal design intent, which is more easily determined from the object’s underlying polyhedral skeleton

Perimeter detection in sketched drawings of polyhedral shapes

Ponència presentada al STAG17: Smart tools and Applications in Graphics, celebrat a Catania (Itàlia) 11-12 setembre 2017This paper describes a new “envelope” approach for detecting object perimeters in line-drawings vectorised from sketches of polyhedral objects. Existing approaches for extracting contours from digital images are unsuitable for Sketch-Based Modelling, as they calculate where the contour is, but not which elements of the line-drawing belong to it. In our approach, the perimeter is described in terms of lines and junctions (including intersections and T-junctions) of the original line drawing

Human Robot Interface for Assistive Grasping

This work describes a new human-in-the-loop (HitL) assistive grasping system for individuals with varying levels of physical capabilities. We investigated the feasibility of using four potential input devices with our assistive grasping system interface, using able-bodied individuals to define a set of quantitative metrics that could be used to assess an assistive grasping system. We then took these measurements and created a generalized benchmark for evaluating the effectiveness of any arbitrary input device into a HitL grasping system. The four input devices were a mouse, a speech recognition device, an assistive switch, and a novel sEMG device developed by our group that was connected either to the forearm or behind the ear of the subject. These preliminary results provide insight into how different interface devices perform for generalized assistive grasping tasks and also highlight the potential of sEMG based control for severely disabled individuals.Comment: 8 pages, 21 figure

Perceiving ribs in single-view wireframe sketches of polyhedral shapes

As part of a strategy for creating 3D models of engineering objects from sketched input, we attempt to identify design features, geometrical structures within objects with a functional meaning. Our input is a 2D B-Rep derived from a single view sketch of a polyhedral shape. In this paper, we show how to use suitable cues to identify algorithmically two additive engineering design features, angular and linear ribs

A fast approach for perceptually-based fitting strokes into elliptical arcs

Fitting elliptical arcs to strokes of an input sketch is discussed. We describe an approach which automatically combines existing algorithms to get a balance of speed and precision. For measuring precision, we introduce fast metrics which are based on perceptual criteria and are tolerant of sketching imperfections. We return a likelihood estimate based on these metrics rather than deterministic yes/no result, in order that the approach can be used in higher-level collaborative-decision recognition flows.1) Ramon y Cajal Scholarship Programme 2) "Pla de Promoció de la Investigació de la Universitat Jaume I", project P1 1B2010-0

Wild camping and the weight of tourism

Wild camping forms a specific social reality within which tourists often claim not to be tourists and within which the capitalist practices central to tourism are messy. Yet, wild camping exemplifies the core idea in tourism: engaging in time during which time is ‘free’. Here the concern is with the ways in which we ‘do’ going camping. We take material interaction with space, place and things as a starting point, via ethnomethodologically informed ethnography, in focusing upon the deployment of mundane, taken-for-granted assumptions, knowledge and practices. We find urban nomads engaged in the clearing, freedom and escape of the outdoors (the lightness), but anchored by the materialities of doing everyday life work, weighted with responsibilities towards nature, things and people

Food tourism and events as tools for social sustainability?

Purpose: Food tourism and events are often prefaced as tools for sustainability within national and intra-national food and agricultural policy contexts. Yet, the realities of enhancing sustainability through food tourism and events are problematic. Sustainability itself is often conceived broadly within policy proclaiming the benefits of food tourism and events, with a need for further deconstruction of the ways each dimension of sustainability – economic, environmental, social and cultural – independently enhances sustainability. The lack of clarity concerning the conceptual utilisation of sustainability works to compromise its value and utilisation for the development of food tourism and events in peripheral areas. In recognition, this paper turns attention to social sustainability within the context of a local food festival, to ask: in what ways is social sustainability enhanced through a local food festival, who benefits from this sustainability, and how? Design: The paper examines the development of a local food festival in a rural coastal community, on Scotland’s west coast. The concept of social capital is utilised to examine the unfolding power relations between committee members, as well as the committee and other social groups. Observant participation undertaken over a 10 month period, between December 2015 and September 2016, renders insights into the ways event planning processes were dependent on the pre-existing accruement of social capital by certain individuals and groups. Findings: Local food festivals have the potential to enhance social sustainability, in offering opportunity to bridge relations across certain diverse groups and foster an environment conducive to cohabitation. Bridging, however, is dependent on preconceived social capital and power relations, which somewhat inhibits social integration for all members of a community. The temporally confined characteristics of events generates difficulties in overcoming the uneven enhancement of social sustainability. Care, thus, needs to be upheld in resolutely claiming enhancement of social sustainability through local food events. Further, broad conceptualisations of ‘community’ need to be challenged during event planning processes; for it is difficult to develop a socially inclusive approach that ensures integration for diverse segments without recognising what constitutes a specific ‘community’. Originality: This paper is situated within the context of a peripheral, yet growing body of literature exploring the potential of events to develop social sustainability. In extending this work, the paper turns attention to the gastronomic - examining the extent to which social sustainability is enhanced through a local food festival, for a rural coastal community – Mallaig, on Scotland’s west coast