Defining the Pose of any 3D Rigid Object and an Associated Distance

The pose of a rigid object is usually regarded as a rigid transformation, described by a translation and a rotation. However, equating the pose space with the space of rigid transformations is in general abusive, as it does not account for objects with proper symmetries -- which are common among man-made objects.In this article, we define pose as a distinguishable static state of an object, and equate a pose with a set of rigid transformations. Based solely on geometric considerations, we propose a frame-invariant metric on the space of possible poses, valid for any physical rigid object, and requiring no arbitrary tuning. This distance can be evaluated efficiently using a representation of poses within an Euclidean space of at most 12 dimensions depending on the object's symmetries. This makes it possible to efficiently perform neighborhood queries such as radius searches or k-nearest neighbor searches within a large set of poses using off-the-shelf methods. Pose averaging considering this metric can similarly be performed easily, using a projection function from the Euclidean space onto the pose space. The practical value of those theoretical developments is illustrated with an application of pose estimation of instances of a 3D rigid object given an input depth map, via a Mean Shift procedure

Do-It-Yourself Single Camera 3D Pointer Input Device

We present a new algorithm for single camera 3D reconstruction, or 3D input for human-computer interfaces, based on precise tracking of an elongated object, such as a pen, having a pattern of colored bands. To configure the system, the user provides no more than one labelled image of a handmade pointer, measurements of its colored bands, and the camera's pinhole projection matrix. Other systems are of much higher cost and complexity, requiring combinations of multiple cameras, stereocameras, and pointers with sensors and lights. Instead of relying on information from multiple devices, we examine our single view more closely, integrating geometric and appearance constraints to robustly track the pointer in the presence of occlusion and distractor objects. By probing objects of known geometry with the pointer, we demonstrate acceptable accuracy of 3D localization.Comment: 8 pages, 6 figures, 2018 15th Conference on Computer and Robot Visio

Tele-autonomous control involving contacts: The applications of a high precision laser line range sensor

The object localization algorithm based on line-segment matching is presented. The method is very simple and computationally fast. In most cases, closed-form formulas are used to derive the solution. The method is also quite flexible, because only few surfaces (one or two) need to be accessed (sensed) to gather necessary range data. For example, if the line-segments are extracted from boundaries of a planar surface, only parameters of one surface and two of its boundaries need to be extracted, as compared with traditional point-surface matching or line-surface matching algorithms which need to access at least three surfaces in order to locate a planar object. Therefore, this method is especially suitable for applications when an object is surrounded by many other work pieces and most of the object is very difficult, is not impossible, to be measured; or when not all parts of the object can be reached. The theoretical ground on how to use line range sensor to located an object was laid. Much work has to be done in order to be really useful

The birds and the bees : gender performance in Grandville's Scènes de la vie privée et publique des animaux

Published between 1840 and 1842, J. J. Grandville’s Scènes de la vie privée et publique des animaux is a hybrid work of satirical allegory that stages the scandals, polemics, and power struggles of the July Monarchy through a collection of illustrations by Grandville and stories written to accompany them. The printed image significantly disrupted artistic hierarchies of the period and sparked heated debates about both the expertise of illustrators and the possibilities of the image, described by Philippe Kaenel as an “instrument of seduction”. Scholarly engagement with Scènes des animaux has all but ignored gender, yet the increased visibility of women in the publishing industry during the July Monarchy permanently altered the terms of modern artistic legitimacy. In this paper, I demonstrate that gender has been conceptualized, represented, and reified in terms of animality and evolutionary discourses in Grandville’s text. Drawing on Alexandra Wettlaufer’s analysis of the dialectic between word and image at play in Scenes des animaux, as well as Bakhtinian polyphony and Eve Sedgwick’s concept of erotic triangles, I consider the work in terms of a triple dialectic between word, image, and gender. Through the figures of bird and bee and their associated verbal tropes, Grandville, Hetzel, and Balzac all link women to consumerism, materialism, stupidity, and sensuality. This set of associations distance women from the field of “legitimate” literary production and disempowers them as sociopolitical agents. At the same time, the overdetermined containment strategies employed by the contributors reveal that they rely on women as their primary reading public and clientele. Economic anxiety has been displaced onto the body of the animal-woman, and the contributors dress up their objections with the accoutrements of conservative morality. In titling this project “The Birds and the Bees” —a euphemism used to explain sex and courtship to small children— I call attention to the persistence of animal metaphors related to gender and sexuality in contemporary culture.Comparative Literatur

Difficult forms: critical practices of design and research

As a kind of 'criticism from within', conceptual and critical design inquire into what design is about – how the market operates, what is considered 'good design', and how the design and development of technology typically works. Tracing relations of conceptual and critical design to (post-)critical architecture and anti-design, we discuss a series of issues related to the operational and intellectual basis for 'critical practice', and how these might open up for a new kind of development of the conceptual and theoretical frameworks of design. Rather than prescribing a practice on the basis of theoretical considerations, these critical practices seem to build an intellectual basis for design on the basis of its own modes of operation, a kind of theoretical development that happens through, and from within, design practice and not by means of external descriptions or analyses of its practices and products