Search results for "Form Perception"
showing 9 items of 29 documents
Attentional vs computational complexity measures in observing paintings
2009
Because of the great heterogeneity of subjects and styles, esthetic perception delineates a special and elusive field of research in vision, which represents an interesting challenge for cognitive science tools. With specific regard to the role of visual complexity, in this paper we present an experiment aimed to measure this dimension in a heterogeneous set of paintings. We compared perceived time complexity measures - based on a temporal estimation paradigm - with physical and statistical properties of the paintings, obtaining a strong correlation between psychological and computational results.
Seeing with the visual cortex
1984
A short analysis of the input-output organization of the primary visual cortical areas in the cat and monkey is followed by a description of the salient microelectrophysiological properties of retino-geniculo-cortical system neurons. It is concluded that a strict hierarchical model of cortical processing of visual information is no longer tenable.
On the classification of visual patterns: systems analysis using detection experiments.
1977
Behavioral experiments are indispensable for the analysis of biological systems for cognition and recognition. When these are carried out as detection experiments three types of description can be used for the problem of visual pattern recognition which allow conclusions to be drawn on the operating function of the system. Provided that the signals to be recognized have additive noise superimposed on them, system description is possible: 1. on the basis on the probabilities of recognition and of mix-up,--2. through the analysis of the transformation of distribution densities of the noise,--3. by means of the measurable distances of the patterns from each other in feature space.-The analysis…
When Geometry Constrains Vision: Systematic Misperceptions within Geometrical Configurations.
2016
International audience; How accurate are we in reproducing a point within a simple shape? This is the empirical question we addressed in this work. Participants were presented with a tiny disk embedded in an empty circle (Experiment 1 and 3) or in a square (Experiment 2). Shortly afterwards the disk vanished and they had to reproduce the previously seen disk position within the empty shape by means of the mouse cursor, as accurately as possible. Several loci inside each shape were tested. We found that the space delimited by a circle and by a square is not homogeneous and the observed distortion appears to be consistent across observers and specific for the two tested shapes. However, a com…
On the analysis of the cat's pattern recognition system
1983
The objective of the paper is to determine in abstract terms the algorithms used by the cat detecting simple patterns and to quantify the contributions of the visual areas 17, 18, 19 for this task. The data incorporated in the algorithm are collected from behavioral experiments where the animals had to distinguish between two patterns. The patterns were superimposed with gaussian noise and the detection probability was measured. The resulting model describes pattern recognition in two steps: first extraction of features and second classification. The test of the validity of the model system was to predict the outcome of similar experiments but with different patterns. With the help of the m…
Does matching of internal and external facial features depend on orientation and viewpoint?
2009
Although it is recognized that external (hair, head and face outline, ears) and internal (eyes, eyebrows, nose, mouth) features contribute differently to face recognition it is unclear whether both feature classes predominately stimulate different sensory pathways. We employed a sequential speed-matching task to study face perception with internal and external features in the context of intact faces, and at two levels of contextual congruency. Both internal and external features were matched faster and more accurately in the context of totally congruent/incongruent facial stimuli compared to just featurally congruent/ incongruent faces. Matching of totally congruent/incongruent faces was no…
Visuospatial deficits in schizophrenia: central executive and memory subsystems impairments
2002
Object and spatial visual working memory are impaired in schizophrenic patients. It is not clear if the impairments reside in each memory subsystem alone or also in the central executive component that coordinates these processes. In order to elucidate which memory component is impaired, we developed a paradigm with single spatial and object working memory tasks and dual ones with two different delays (5 and 30 s). Fifteen schizophrenic patients and 14 control subjects performed these tests. Schizophrenic patients had a poorer performance compared to normal controls in all tasks and in all time delays. Both schizophrenics and controls performed significantly worse in the object task than in…
Extraction of objects from structured backgrounds in the cat superior colliculus. Part II
1980
Specific changes occur in the cells of the uppers layers of the cat's superior colliculus when a two dimensional noise (background) is superimposed onto a deterministic signal (spot of light). Some of the measurements can be interpreted as meaning that some cells only react to certain relative movements of object (spot) and background (noise). The movement of the visual background is interpreted as environmental movement occurring due to the animal's own movement. The results of the measurements provide all the necessary presuppositions for a distinction between the animal's own velocity and that of the object (Part I). The experimental results can be interpreted with a model. The essential…
Effect of Repetition and Inspection Times on Picture Recall in Patients with Dementia of Alzheimer Type
1997
The present study is part of a series of systematic studies intended to identify simple strategies of picture presentation to improve recall performance in demented subjects. The aims of this design were to examine the effects of elaboration by naming, 4-fold repetition and different inspection times on memory performance. 19 patients with senile dementia of Alzheimer type and 21 control subjects with remitted depression were included. Picture recall was examined using different presentation conditions on 5 consecutive days. The presentation conditions significantly influenced recall performance depending on the diagnosis and on the delay of recall. Naming of pictures did not improve later …