Unlike fixed cameras, which are limited to a static view of the scene, active cameras are capable of changing their view by means of, for instance, rotation (pan and tilt) and zoom. Cameras with these particular capabilities are known as PTZ (pan-tilt-zoom) cameras, and are widely employed in surveillance for viewing and tracking under dynamic conditions. By shifting to and zooming on a target, PTZ cameras can capture fine-grained detail, such as face and hands.… Read more
Human activity recognition based on wearable sensors has received great attention in areas such as healthcare, homeland security and smart environments, mainly because it enables easy data acquisition and processing. This task consists of assigning a category of activity to signals provided by wearable sensors such as accelerometers, gyroscopes and magnetometers.
The human brain is able to rapidly understand scenes through the recognition of their composing elements and comprehension of the role that each of them plays. This process, related to human perception, impacts in what people care when they see an image and the priority they give to each element. The idea of priority, also referred as importance, is based on biological features of perception and social aspects that interfere in how people perceive what they see and what is considered relevant.… Read more
Activity recognition has become a very active area in the past few years. It is a challenging problem that has attracted the attention of the research community due to its practical and real-world applications, such as human computer interfaces, content based video indexing, video surveillance, and robotics, among others. A definition for such task can be described as labeling video segments containing human motion with activity classes.… Read more
Clustering techniques have been widely used in areas that handle massive amounts of data, such as statistics, information retrieval, data mining and image analysis.
An increasing volume of digital images and videos has become available over the years due to the growth of smartphones, tablets and Internet of Things in general. Therefore, the development of techniques capable of managing large amount of data in a fast and accurate way is important to extract any valuable information.… Read more
During the last years, the task of automatic event analysis in video sequences has gained an increasing attention among the research community. In surveillance systems anomaly behavior is a very important task. Actually, this task is performed by humans. Automatizing this task is pretty complicated since exist infinity possible situations if we think in a scalable automatic surveillance. To reduce the complexity we may look for patterns, normal and anomalous.… Read more
ALPR is a field in which many researchers have been working over the years. This reflect the important role that it plays in numerous real-life applications such as automatic toll collection, traffic law enforcement, parking lot access control and road traffic monitoring. The process of license plates automatic identification is composed by single tasks that must work as well. Examples of these are car and plate detection, character segmentation, optical character recognition and others.… Read more
Person re-identification deals with automatically tracking individuals across cameras without overlapping field of view. It is an important task to assist security personnel to monitor pedestrian behavior at wider areas with reduced costs. In person re-identification, we have a gallery set and the objective is to match a probe image with one of these individuals. Using image pairs, present in the training set, we can learn similarity models. … Read more
Computer Vision problems applied to visual surveillance have been studied for several years aiming at finding accurate and efficient solutions, required to allow the execution of surveillance systems in real environments. The main goal of such systems is to analyze the scene focusing on the detection and recognition of suspicious activities performed by humans in the scene, so that the security personnel can pay closer attention to these preselected activities.… Read more
The three primary face recognition tasks are verification, identification, and watch list. In verification, the task is to accept or deny the identity claimed by a person. In identification, an image of an unknown person is matched to a gallery of known people. In the watch list task, a face recognition system must first detect if an individual is on the watch list.… Read more
Effective techniques for human detection are of special interest in computer vision since many applications involve people’s locations and movements. Thus, significant research has been devoted to detecting, locating and tracking people in images and videos. Over the last few years the problem of detecting humans in single images has received considerable interest. Variations in illumination, shadows, and pose, as well as frequent inter- and intra-person occlusion render this a challenging task.… Read more
Information regarding changes in a scene plays a central role in a myriad of applications. Disaster management, urban growth, security, burned areas, and surveillance are examples of problems which the knowledge of local changes is essential. In general, video monitoring performed by humans is error prone due to the known lack of attention in repetitive tasks that take may many hours.… Read more
Nowadays, we are experiencing an increasing demand for highly secure identification and personal verification technologies. This demand becomes even more apparent as we become aware of new security breaches and transaction frauds. In this context, biometrics has played a key role in the last decade providing tools and solutions either to verify or recognize the identity of a person based on physiological or behavioral characteristics.… Read more
The traffic light is one of the valuable devices to control the vehicular and pedestrian traffic. One of its main issues is that several traffic lights might be improperly calibrated once they do not consider the differences in pedestrian mobility from region to region. As each region presents different pedestrians with different characteristics, there is a need for automatic approaches. In this work, we propose a new approach to automatically adjust the pedestrian traffic light program to provide greater safety for pedestrians and to allow a better flow of the traffic.… Read more
Visual information contained in images is usually represented by low-level feature descriptors focusing on different types of information, such as color, texture, and shape. An adequate feature descriptor is able to discriminate between regions with different characteristics and it allows similar regions to be grouped together even when captured under noisy conditions. However, it is usually difficult to have a single feature descriptor adequate for many application domains; this has motivated researchers to develop a variety of feature extraction methods.… Read more