1,721,311 research outputs found
Advanced Studies in Biometrics
No full textThe ability to automatically recognize an individual has increasingly been acknowledged as a significant step in many application domains. In the last decade, several recognition and identification systems have been utilized: fingerprints, face and facial features, retinal scans, iris patterns, hand geometry, DNA traces, and gait, and others. Not only have research tools been developed, but a notable number of new applications have been observed, making studies on biometrics a very stimulating but also challenging area
Première partie - À propos de quelques nouveautés dans la jurisprudence de la cour constitutionnelle italienne en 1993
No full textGiorgis Andrea, Grosso Enrico, Luther Jörg. Première partie - À propos de quelques nouveautés dans la jurisprudence de la cour constitutionnelle italienne en 1993 . In: Annuaire international de justice constitutionnelle, 9-1993, 1995. Constitutions et partis politiques. pp. 531-543
On the importance of local and global analysis in the judgment of similarity and dissimilarity of faces
No full textThe ability to recognize faces and to detect differences and similarities between faces has proved to be fundamental in the evolution of humans and in the conditioning of their social behaviors. In this paper, we investigate basic mechanisms underlying this ability, focusing in particular on the relevance of local and global features and on some interesting differences characterizing judgments of similarity with respect to judgments of dissimilarity.In a first experiment, a set of participants is involved in order to evaluate the human response with respect to a simple judgment protocol based on two-alternative forced choice. Triplets of face stim uli are evaluated first with the aim of identifying (between two candidate faces) the face more similar to a reference face. The protocol is then repeated for the same triplets but involving a different set of participants and asking to identify the face less similar to a reference face. These visual judgments of similarity and dissimilarity are finally analyzed and compared with the results of a closely related computational experiment based on the same set of triplets: in this case, however, the similarity-dissimilarity measure is derived by automatically extracting facial points and matching with regression techniques (LASSO and Elastic Net) two configurations of image descriptors: the first capturing holistic information, the second capturing local information, that is few localized facial features.Our results suggest that computational models based on holistic cues (emphasizing the concept of the whole as a composed set of interdependent parts) better fit judgments of humans participating to the first experiment (similarity judgments). On the other hand, models based on spatially localized cues do not offer significant accuracy. Vice versa, computational models based on local cues better fit dissimilarity judgments and are less adequate to express similarity information. Notably, our results provide some empirical evidence that local and global cues are both important in face perception, but with different roles. This finding supports the hypothesis that similarity and dissimilarity should not merely be considered as opposing concepts, as they could derive from different processing paths. (C) 2019 Elsevier B.V. All rights reserved
On testing methods for biometric authentication
Full text linkThe use of biometric data for user authentication and/or
recognition is now a reality. On the other hand, there is
still a strong need for new technologies to overpass
intrinsic limitations of already “established” techniques.
This not only requires to devise new algorithms but to
determine the real potential and limitations of existing
techniques. This is possible only devising standard testing
and assessment procedures based on statistical
observations of the outputs of the system. In order to
define better a standard evaluation process, a system based
on space-variant iconic image matching is described and
the validation procedure defined. I turns out that all
methods based on the same biometric measurements have
the same intrinsic limitations, which can be only overcome
by the adoption of a multi-modal or multi-algorithmic
approach
Active face recognition with a hybrid approach
No full textThe automatic detection of person's identity is a very interesting issue both in social and industrial environments. In this paper a system for automatic identity recognition from face images, is presented. The proposed approach is based on an hybrid iconic approach, where a first recognition score is obtained by matching a person's face against an eigen-space obtained from an image ensemble of known individuals. The hypothesis is then verified by computing the correlation of the gray level histogram of the new face image with the histograms of the subjects in the database. A selective attentional mechanism is applied to reduce the amount of information needed to describe a database of human faces. This is accomplished both at the task level, by performing planned fixations, and at the sensor level, by adopting a space-variant sampling of the images. By using a space-variant image geometry, the size of the database is considerably reduced and consequently also the processing time for recognition
ACTIVE DYNAMIC STEREO VISION
Full text linkVisual navigation is a challenging issue in automated
robot control. In many robot applications, like object manipulation
in hazardous environments or autonomous locomotion, it is
necessary to automatically detect and avoid obstacles while planning
a safe trajectory. In this context the detection of corridors of
free space along the robot trajectory is a very important capability
which requires nontrivial visual processing. In most cases it is
possible to take advantage of the active control of the cameras.
In this paper we propose a cooperative schema in which motion
and stereo vision are used to infer scene structure and determine
free space areas. Binocular disparity, computed on several
stereo images over time, is combined with optical flow from
the same sequence to obtain a relative-depth map of the scene.
Both the time-to-impact and depth scaled by the distance of the
camera from the fixation point in space are considered as good,
relative measurements which are based on the viewer, but centered
on the environment.The need for calibrated parameters is considerably reduced by
using an active control strategy. The cameras track a point in
space independently of the robot motion and the full rotation of
the head, which includes the unknown robot motion, is derived
from binocular image data.The feasibility of the approach in real robotic applications is
demonstrated by several experiments performed on real image
data acquired from an autonomous vehicle and a prototype camera
head
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