The Influence of Spatial Reference Frames on Imagined Object-and vVewer Rotations

The human visual system can represent an object\u27s spatial structure with respect to multiple frames of reference. It can also utilize multiple reference frames to mentally transform such representations. Recent studies have shown that performance on some mental transformations is not equivalent: Imagined object rotations tend to be more difficult than imagined viewer rotations. We reviewed several related research domains to understand this discrepancy in terms of the different reference frames associated with each imagined movement. An examination of the mental rotation literature revealed that observers\u27 difficulties in predicting an object\u27s rotational outcome may stem from a general deficit with imagining the cohesive rotation of the object\u27s intrinsic frame. Such judgments are thus more reliant on supplementary information provided by other frames, such as the environmental frame. In contrast, as assessed in motor imagery and other studies, imagined rotations of the viewer\u27s relative frame are performed cohesively and are thus mostly immune to effects of other frames. © 1999 Elsevier Science B.V. All rights reserved

Intelligent Automatic Interpretation of Active Marine Sonar

This dissertation explores the problems raised by the design and construction of a real-time sonar interpreter operating in a three dimensional marine context, and then focusses on two major research issues inherent in sonar interpretation: the treatment of observer and object motion, and the efficient exploitation of the specularity of acoustic reflection. The theoretical results derived in these areas have been tested where appropriate by computer simulation. In the context of mobile marine robotics, the registration of sensory data obtained from differing viewpoints is of paramount importance. Small marine vehicles of the type considered here do not carry sophisticated navigational equipment, and cannot be held stationary in the water for any length of time. The viewpoint registration problem is defined and analysed in terms of the new problem of motion resolution: the task of resolving the apparent motion of objects into that part due to the movement of the observer and that due to the objects' proper motion. Two solutions to this under constrained problem are presented. The first presupposes that the observer orientation is known ~ priori so that only the translational observer motion must be determined. It is applicable to two and three-dimensional situations. The second solution determines both the translational and the rotational motion of the observer, but is restricted to a two-dimensional situation. Both solutions are based on target extensively tested in two tracking techniques, and have dimensions by computer simulation. been The necessary extensions to deal with full three-dimensional motion are also discussed. The second major research issue addressed in this thesis is the efficient use of specularity. Specular echoes have a high intrinsic information content because of the alignment conditions necessary for their generation. In the marine acoustic context they provide a significant proportion of the information available from an acoustic ranger. I suggest a new method that uses directly the information present in specular reflections and the history of the vehicle motion to classify the specular echo sources and infer the local structure of the objects bearing them. The method builds on the output of a motion resolution system. Six distinct types of specular echo source are described and three properties useful for their discrimination are discussed. A suitable inference system for the analysis and classification of specular echo sources is also proposed

Knowledge-based vision and simple visual machines

The vast majority of work in machine vision emphasizes the representation of perceived objects and events: it is these internal representations that incorporate the 'knowledge' in knowledge-based vision or form the 'models' in model-based vision. In this paper, we discuss simple machine vision systems developed by artificial evolution rather than traditional engineering design techniques, and note that the task of identifying internal representations within such systems is made difficult by the lack of an operational definition of representation at the causal mechanistic level. Consequently, we question the nature and indeed the existence of representations posited to be used within natural vision systems (i.e. animals). We conclude that representations argued for on a priori grounds by external observers of a particular vision system may well be illusory, and are at best place-holders for yet-to-be-identified causal mechanistic interactions. That is, applying the knowledge-based vision approach in the understanding of evolved systems (machines or animals) may well lead to theories and models that are internally consistent, computationally plausible, and entirely wrong

Vision and Action

(Also cross-referenced as CAR-TR-722) Our work on Active Vision has recently focused on the computational modelling of navigational tasks, where our investigations were guided by the idea of approaching vision for behavioral systems in form of modules that are directly related to perceptual tasks. These studies led us to branch in various directions and inquire into the problems that have to be addressed in order to obtain an overall understanding of perceptual systems. In this paper we present our views about the architecture of vision syst ems, about how to tackle the design and analysis of perceptual systems, and promising future research directions. Our suggested approach for understanding behavioral vision to realize the relationship of perception and action builds on two earlier approac hes, the Medusa philosophy 13] and the Synthetic approach [15 The resulting framework calls for synthesizing an artificial vision system by studying vision corr petences of increasing complexity and at the same time pursuing the integration of the percept ual components with action and learning modules. We expect that Computer Vision research in the future will progress in tight collaboration with many other disciplines that are concerned with empirical approaches to vision, i.e. the understanding of biolo gical vision. Throughout the paper we describe biological findings that motivate computational arguments which we believe will influence studies of Computer Vision in the near future

Seeing Government Purpose Through the Objective Observer\u27s Eyes: The Evolution-Intelligent Design Debates

In October, 2004, the Dover, Pennsylvania School District became the first in the nation to adopt a policy requiring students studying evolution to be told about the concept of intelligent design. Soon thereafter, parents filed a lawsuit challenging the policy as violating the Establishment Clause. But, Establishment Clause doctrine is one of the most splintered, incoherent areas of the Court’s jurisprudence—and even more so after the Court’s June 2005 McCreary County v. Kentucky decision. Read strictly, McCreary County imports the effects-endorsement “objective observer” into the government purpose inquiry. This subtle shift has significant ramifications: McCreary County changes the nature of the constitutional harm from an allegedly impermissible actual purpose to apparent purpose; results in an objective observer with a bizarrely expansive knowledge of issues of law but more limited knowledge of issues of fact; and requires de novo review throughout the circuits which previously were split on the proper standard of review for a government purpose inquiry. Analyzing McCreary County’s meaning in the context of the intelligent design debates shows that while McCreary County’s general focus on government purpose is helpful, the objective observer’s perspective on government purpose does more doctrinal harm than good. Thus, courts should return the reasonable observer to the effects-endorsement aspect of the Establishment Clause analysis

Le Corbusier between sketches. A graphic analysis of the Acropolis sketches

[EN] In contrast to Le Corbusier's later written accounts and the opinions critics have formed from these texts, this article concentrates on the ideas and opinions Le Corbusier developed in-situ during his first visit to the Acropolis in 1911. Using a detailed method of graphic analysis, this research deconstructs a set of Le Corbusier’s original sketches of the Acropolis made in Carnet 3 during his Voyage d’Orient in 1911. Comparing them in chronological sequence reveals how the ideas of the architect evolved whilst he was immersed in the physical experience of the Acropolis. The article focuses on two themes prevalent in the sketches and also in his later work: The various relationships between architecture and ground; and the representation of dynamic spatial experience across time and space. It finds that Le Corbusier used in-situ sketching as an intentional and rigorous method to analyse the Acropolis, actively forming his opinions through experimentation and refinement rather than merely illustrating pre-established ideas. This analysis reveals how Le Corbusier made use of his prior knowledge of the Acropolis but also, how he used his sketches to gradually transform this into a personal and original interpretation of the site and its buildings. It also shows that a number of his most celebrated ideas are not present in these sketches and may have developed in retrospect under the influence of other authors.[ES] Este artículo se centra en las ideas y opiniones de Le Corbusier desarrolladas in-situ durante su primera visita a la Acrópolis en 1911 y contrasta con escritos posteriores del propio Le Corbusier e historiadores de estos textos. Este artículo deconstruye una serie croquis originales dibujados por Le Corbusier en el Carnet 3 de su Viaje al Oriente a través de un análisis gráfico detallado. Comparando sus croquis originales en secuencia cronológica revela como las ideas del arquitecto evolucionaron mientras que estaba inmerso en la experiencia física de la Acrópolis. El artículo se enfoca en dos temas predominantes que son presentes tanto en los croquis como en su obra posterior: Las relaciones entre la arquitectura y el terreno; y la representación de la experiencia espacio-temporal del conjunto arquitectónico. El artículo argumenta que Le Corbusier utilizaba sus croquis in-situ como método intencional y riguroso para analizar la arquitectura formando sus opiniones por experimentación y refinamiento más que para ilustrar conceptos preestablecidos. Este análisis muestra como Le Corbusier aprovechaba sus conocimientos previos de la Acrópolis, además de transformarlos gradualmente por medio de sus croquis en una interpretación personal y original del lugar y de la arquitectura. También explica que varias de sus ideas más celebradas no están presentes en estos croquis y que las desarrolló retrospectivamente bajo la influencia de otros autores.Harris, S. (2016). Le Corbusier between sketches. A graphic analysis of the Acropolis sketches. En LE CORBUSIER. 50 AÑOS DESPUÉS. Editorial Universitat Politècnica de València. 975-992. https://doi.org/10.4995/LC2015.2015.911OCS97599

Realism and Explanatory Perspectivism

This chapter defends a (minimal) realist conception of progress in scientific understanding in the face of the ubiquitous plurality of perspectives in science. The argument turns on the counterfactual-dependence framework of explanation and understanding, which is illustrated and evidenced with reference to different explanations of the rainbow