Stochastic Functional Analysis and Multilevel Vector Field Anomaly
Detection
- URL: http://arxiv.org/abs/2207.06229v1
- Date: Mon, 11 Jul 2022 13:11:16 GMT
- Title: Stochastic Functional Analysis and Multilevel Vector Field Anomaly
Detection
- Authors: Julio E Castrillon-Candas and Mark Kon
- Abstract summary: We develop a novel analysis approach for detecting anomalies in massive vector field datasets.
An optimal vector field Karhunen-Loeve (KL) expansion is applied to such random field data.
The method is applied to the problem of deforestation and degradation in the Amazon forest.
- Score: 0.0
- License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
- Abstract: Massive vector field datasets are common in multi-spectral optical and radar
sensors and modern multimodal MRI data, among many other areas of application.
In this paper we develop a novel stochastic functional analysis approach for
detecting anomalies based on the covariance structure of nominal stochastic
behavior across a domain with multi-band vector field data. An optimal vector
field Karhunen-Loeve (KL) expansion is applied to such random field data. A
series of multilevel orthogonal functional subspaces is constructed from the
geometry of the domain, adapted from the KL expansion. Detection is achieved by
examining the projection of the random field on the multilevel basis. The
anomalies can be quantified in suitable normed spaces based on local and global
information. In addition, reliable hypothesis tests are formed with
controllable distributions that do not require prior assumptions on probability
distributions of the data. Only the covariance function is needed, which makes
for significantly simpler estimates. Furthermore this approach allows
stochastic vector-based fusion of anomalies without any loss of information.
The method is applied to the important problem of deforestation and degradation
in the Amazon forest. This is a complex non-monotonic process, as forests can
degrade and recover. This particular problem is further compounded by the
presence of clouds that are hard to remove with current masking algorithms.
Using multi-spectral satellite data from Sentinel 2, the multilevel filter is
constructed and anomalies are treated as deviations from the initial state of
the forest. Forest anomalies are quantified with robust hypothesis tests and
distinguished from false variations such as cloud cover. Our approach shows the
advantage of using multiple bands of data in a vectorized complex, leading to
better anomaly detection beyond the capabilities of scalar-based methods.
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