55,922 research outputs found
Attention mechanisms in the CHREST cognitive architecture
In this paper, we describe the attention mechanisms in CHREST, a computational architecture of human visual expertise. CHREST organises information acquired by direct experience from the world in the form of chunks. These chunks are searched for, and verified, by a unique set of heuristics, comprising the attention mechanism. We explain how the attention mechanism combines bottom-up and top-down heuristics from internal and external sources of information. We describe some experimental evidence demonstrating the correspondence of CHREST’s perceptual mechanisms with those of human subjects. Finally, we discuss how visual attention can play an important role in actions carried out by human experts in domains such as chess
Top-down effects on early visual processing in humans: a predictive coding framework
An increasing number of human electroencephalography (EEG) studies examining the earliest component of the visual evoked potential, the so-called C1, have cast doubts on the previously prevalent notion that this component is impermeable to top-down effects. This article reviews the original studies that (i) described the C1, (ii) linked it to primary visual cortex (V1) activity, and (iii) suggested that its electrophysiological characteristics are exclusively determined by low-level stimulus attributes, particularly the spatial position of the stimulus within the visual field. We then describe conflicting evidence from animal studies and human neuroimaging experiments and provide an overview of recent EEG and magnetoencephalography (MEG) work showing that initial V1 activity in humans may be strongly modulated by higher-level cognitive factors. Finally, we formulate a theoretical framework for understanding top-down effects on early visual processing in terms of predictive coding
From perception to action and vice versa: a new architecture showing how perception and action can modulate each other simultaneously
Presentado en: 6th European Conference on Mobile Robots (ECMR) Sep 25-27, 2013 Barcelona, SpainArtificial vision systems can not process all the
information that they receive from the world in real time
because it is highly expensive and inefficient in terms of
computational cost. However, inspired by biological perception
systems, it is possible to develop an artificial attention model
able to select only the relevant part of the scene, as human
vision does. From the Automated Planning point of view, a
relevant area can be seen as an area where the objects involved
in the execution of a plan are located. Thus, the planning system
should guide the attention model to track relevant objects. But,
at the same time, the perceived objects may constrain or provide
new information that could suggest the modification of a current
plan. Therefore, a plan that is being executed should be adapted
or recomputed taking into account actual information perceived
from the world. In this work, we introduce an architecture that
creates a symbiosis between the planning and the attention
modules of a robotic system, linking visual features with high
level behaviours. The architecture is based on the interaction of
an oversubscription planner, that produces plans constrained
by the information perceived from the vision system, and an
object-based attention system, able to focus on the relevant
objects of the plan being executed.Spanish MINECO projects TIN2008-06196, TIN2012-38079-C03-03 and TIN2012-38079-C03-02. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec
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