2,305 research outputs found
Phototaxic foraging of the archaepaddler, a hypothetical deep-sea species
An autonomous agent (animat, hypothetical animal), called the (archae) paddler, is simulated in sufficient detail to regard its simulated aquatic locomotion (paddling) as physically possible. The paddler is supposed to be a model of an animal that might exist, although it is perfectly possible to view it as a model of a robot that might be built. The agent is assumed to navigate in a simulated deep-sea environment, where it hunts autoluminescent prey. It uses a biologically inspired phototaxic foraging-strategy, while paddling in a layer just above the bottom. The advantage of this living space is that the navigation problem is essentially two-dimensional. Moreover, the deep-sea environment is physically simple (and hence easier to simulate): no significant currents, constant temperature, completely dark. A foraging performance metric is developed that circumvents the necessity to solve the travelling salesman problem. A parametric simulation study then quantifies the influence of habitat factors, such as the density of prey, and the body-geometry (e.g. placement, direction and directional selectivity of the eyes) on foraging success. Adequate performance proves to require a specific body-% geometry adapted to the habitat characteristics. In general performance degrades smoothly for modest changes of the geometric and habitat parameters, indicating that we work in a stable region of 'design space'. The parameters have to strike a compromise between on the one hand the ability to 'fixate' an attractive target, and on the other hand to 'see' as many targets at the same time as possible. One important conclusion is that simple reflex-based navigation can be surprisingly efficient. In the second place, performance in a global task (foraging) depends strongly on local parameters like visual direction-tuning, position of the eyes and paddles, etc. Behaviour and habitat 'mould' the body, and the body-geometry strongly influences performance. The resulting platform enables further testing of foraging strategies, or vision and locomotion theories stemming either from biology or from robotics
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Virtual viewpoint three-dimensional panorama
Conventional panoramic images are known to provide for an enhanced field of view in which the scene
always has a fixed appearance. The idea presented in this paper focuses on the use of the concept of virtual
viewpoint creation to generate different panoramic images of the same scene with three-dimensional
component. Three-dimensional effect in a resultant panorama is realized by superimposing a stereo-pair of
panoramic images
Aerospace medicine and biology: A continuing bibliography with indexes, supplement 204
This bibliography lists 140 reports, articles, and other documents introduced into the NASA scientific and technical information system in February 1980
Cortical Dynamics of 3-D Surface Perception: Binocular and Half-Occluded Scenic Images
Previous models of stereopsis have concentrated on the task of binocularly matching left and right eye primitives uniquely. A disparity smoothness constraint is often invoked to limit the number of possible matches. These approaches neglect the fact that surface discontinuities are both abundant in natural everyday scenes, and provide a useful cue for scene segmentation. da Vinci stereopsis refers to the more general problem of dealing with surface discontinuities and their associated unmatched monocular regions within binocular scenes. This study develops a mathematical realization of a neural network theory of biological vision, called FACADE Theory, that shows how early cortical stereopsis processes are related to later cortical processes of 3-D surface representation. The mathematical model demonstrates through computer simulation how the visual cortex may generate 3-D boundary segmentations and use them to control filling-in of 3-D surface properties in response to visual scenes. Model mechanisms correctly match disparate binocular regions while filling-in monocular regions with the correct depth within a binocularly viewed scene. This achievement required introduction of a new multiscale binocular filter for stereo matching which clarifies how cortical complex cells match image contours of like contrast polarity, while pooling signals from opposite contrast polarities. Competitive interactions among filter cells suggest how false binocular matches and unmatched monocular cues, which contain eye-of-origin information, arc automatically handled across multiple spatial scales. This network also helps to explain data concerning context-sensitive binocular matching. Pooling of signals from even-symmetric and odd-symmctric simple cells at complex cells helps to eliminate spurious activity peaks in matchable signals. Later stages of cortical processing by the blob and interblob streams, including refined concepts of cooperative boundary grouping and reciprocal stream interactions between boundary and surface representations, arc modeled to provide a complete simulation of the da Vinci stereopsis percept.Office of Naval Research (N00014-95-I-0409, N00014-85-1-0657, N00014-92-J-4015, N00014-91-J-4100); Airforce Office of Scientific Research (90-0175); National Science Foundation (IRI-90-00530); The James S. McDonnell Foundation (94-40
Stereo Matching in Address-Event-Representation (AER) Bio-Inspired Binocular Systems in a Field-Programmable Gate Array (FPGA)
In stereo-vision processing, the image-matching step is essential for results, although it
involves a very high computational cost. Moreover, the more information is processed, the more time
is spent by the matching algorithm, and the more ine cient it is. Spike-based processing is a relatively
new approach that implements processing methods by manipulating spikes one by one at the time
they are transmitted, like a human brain. The mammal nervous system can solve much more complex
problems, such as visual recognition by manipulating neuron spikes. The spike-based philosophy
for visual information processing based on the neuro-inspired address-event-representation (AER)
is currently achieving very high performance. The aim of this work was to study the viability of a
matching mechanism in stereo-vision systems, using AER codification and its implementation in
a field-programmable gate array (FPGA). Some studies have been done before in an AER system
with monitored data using a computer; however, this kind of mechanism has not been implemented
directly on hardware. To this end, an epipolar geometry basis applied to AER systems was studied
and implemented, with other restrictions, in order to achieve good results in a real-time scenario.
The results and conclusions are shown, and the viability of its implementation is proven.Ministerio de Economía y Competitividad TEC2016-77785-
Aerospace Medicine and Biology: A continuing bibliography with indexes, supplement 140
This bibliography lists 306 reports, articles, and other documents introduced into the NASA scientific and technical information system in March 1975
Beyond Gazing, Pointing, and Reaching: A Survey of Developmental Robotics
Developmental robotics is an emerging field located
at the intersection of developmental psychology
and robotics, that has lately attracted
quite some attention. This paper gives a survey of
a variety of research projects dealing with or inspired
by developmental issues, and outlines possible
future directions
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