Search results for "change detection"

A context-aware approach for long-term behavioural change detection and abnormality prediction in ambient assisted living

2015

This research aims to describe pattern recognition models for detecting behavioural and health-related changes in a patient who is monitored continuously in an assisted living environment. The early anticipation of anomalies can improve the rate of disease prevention. Here we present different learning techniques for predicting abnormalities and behavioural trends in various user contexts. In this paper we described a Hidden Markov Model based approach for detecting abnormalities in daily activities, a process of identifying irregularity in routine behaviours from statistical histories and an exponential smoothing technique to predict future changes in various vital signs. The outcomes of t…

Anomaly and Change Detection in Remote Sensing Images

2021

Earth observation through satellite sensors, models and in situ measurements provides a way to monitor our planet with unprecedented spatial and temporal resolution. The amount and diversity of the data which is recorded and made available is ever-increasing. This data allows us to perform crop yield prediction, track land-use change such as deforestation, monitor and respond to natural disasters and predict and mitigate climate change. The last two decades have seen a large increase in the application of machine learning algorithms in Earth observation in order to make efficient use of the growing data-stream. Machine learning algorithms, however, are typically model agnostic and too flexi…

Auditory cortical and hippocampal local-field potentials to frequency deviant tones in urethane-anesthetized rats: An unexpected role of the sound fr…

2015

The human brain can automatically detect auditory changes, as indexed by the mismatch negativity of event-related potentials. The mechanisms that underlie this response are poorly understood. We recorded primary auditory cortical and hippocampal (dentate gyrus, CA1) local-field potentials to serial tones in urethane-anesthetized rats. In an oddball condition, a rare (deviant) tone (p = 0.11) randomly replaced a repeated (standard) tone. The deviant tone was either lower (2200, 2700, 3200, 3700 Hz) or higher (4300, 4800, 5300, 5800 Hz) in frequency than the standard tone (4000 Hz). In an equiprobability control condition, all nine tones were presented at random (p = 0.11). Differential respo…

Memory-Based Mismatch Response to Frequency Changes in Rats

2011

Any occasional changes in the acoustic environment are of potential importance for survival. In humans, the preattentive detection of such changes generates the mismatch negativity (MMN) component of event-related brain potentials. MMN is elicited to rare changes (‘deviants’) in a series of otherwise regularly repeating stimuli (‘standards’). Deviant stimuli are detected on the basis of a neural comparison process between the input from the current stimulus and the sensory memory trace of the standard stimuli. It is, however, unclear to what extent animals show a similar comparison process in response to auditory changes. To resolve this issue, epidural potentials were recorded above the pr…

Unsupervised Anomaly and Change Detection With Multivariate Gaussianization

2022

Anomaly detection (AD) is a field of intense research in remote sensing (RS) image processing. Identifying low probability events in RS images is a challenging problem given the high dimensionality of the data, especially when no (or little) information about the anomaly is available a priori. While a plenty of methods are available, the vast majority of them do not scale well to large datasets and require the choice of some (very often critical) hyperparameters. Therefore, unsupervised and computationally efficient detection methods become strictly necessary, especially now with the data deluge problem. In this article, we propose an unsupervised method for detecting anomalies and changes …

Editorial : Visual mismatch negativity (vMMN) : A unique tool in investigating automatic processing

2022

Unsupervised change detection with kernels

2012

In this paper an unsupervised approach to change detection relying on kernels is introduced. Kernel based clustering is used to partition a selected subset of pixels representing both changed and unchanged areas. Once the optimal clustering is obtained the estimated representatives (centroids) of each group are used to assign the class membership to all others pixels composing the multitemporal scenes. Different approaches of considering the multitemporal information are considered with accent on the computation of the difference image directly in the feature spaces. For this purpose a difference kernel approach is successfully adopted. Finally an effective way to cope with the estimation o…

Implicit binding of facial features during change blindness

2014

Change blindness refers to the inability to detect visual changes if introduced together with an eye-movement, blink, flash of light, or with distracting stimuli. Evidence of implicit detection of changed visual features during change blindness has been reported in a number of studies using both behavioral and neurophysiological measurements. However, it is not known whether implicit detection occurs only at the level of single features or whether complex organizations of features can be implicitly detected as well. We tested this in adult humans using intact and scrambled versions of schematic faces as stimuli in a change blindness paradigm while recording event-related potentials (ERPs). …

Lost in space? Using geo-narratives to interpret land use changes in a rural landscape of inner Sicily

2021

Intercropping landscapes characterised by the presence of certain plant features (i.e. old-century olive trees) are usually considered traditional landscapes, extremely important for their biocultural heritage. Olive agroforestry systems were widespread in the past throughout Sicily. Recent evolution processes involving intensification have switched to olive grove monocultures. Here we present ongoing work on the application of geo-narratives to interpret transformation dynamics of land use practices in a rural landscape of inner Sicily. Based on the assumption that spatial patterns are the expression of transformation processes, where the spatial variation of human activities is a signific…

Anger superiority effect for change detection and change blindness

2013

Abstract In visual search, an angry face in a crowd “pops out” unlike a happy or a neutral face. This “anger superiority effect” conflicts with views of visual perception holding that complex stimulus contents cannot be detected without focused top-down attention. Implicit visual processing of threatening changes was studied by recording event-related potentials (ERPs) using facial stimuli using the change blindness paradigm, in which conscious change detection is eliminated by presenting a blank screen before the changes. Already before their conscious detection, angry faces modulated relatively early emotion sensitive ERPs when appearing among happy and neutral faces, but happy faces only…