Massimo Sciotti

SAR prescreening using both target and shadow information

The utility of fusing shadow and intensity detections in a SAR prescreener is evaluated over the MSTAR database. We use either power ratio, GLRT or two-parameter CFAR tests to extract the two detections. For any testing strategy, the addition of shadow information improves performance.

Optimum model-based segmentation techniques for multifrequency polarimetric SAR images of urban areas

A new technique, named diagonal polarimetric merge-using-moments (DPOL MUM), is proposed for the segmentation of multifrequency polarimetric synthetic aperture radar (SAR) images that exploits the characteristic block diagonal structure of their covariance matrix. This technique is based on the newly introduced split-merge test, which has a reduced fluctuation error than the straight extension of the polarimetric test (POL MUM) and is shown to yield a more accurate segmentation on simulated SAR images. DPOL MUM is especially useful in the extraction of information from urban areas that are characterized by the presence of different spectral and polarimetric characteristics. Its effectiveness is demonstrated by applying it to segment a set of SIR-C images of the town of Pavia. The classification of the image segmented with DPOL MUM shows higher probability of correct classification compared to POL MUM and to a similar technique that does not use the correlation properties (MT MUM).

Maritime multi-sensor data association based on geographic and navigational knowledge

The integration of current traffic monitoring operational systems in the field of maritime surveillance is widely acknowledged as a key requirement for borders control and illegal trafficking prevention. In this paper, an overview of the satellite-extended-vessel traffic service (SEV) system for in-situ and earth observation (EO) data association is presented. The description of the cognitive data correlation concept shows the benefits brought to the resulting maritime recognised picture (RMP) in supporting decision making and situation awareness applications.

Polarimetric detectors of extended targets for ship detection in SAR images

This paper deals with polarimetric detection of ships in SAR images of medium/high resolution (about meters). The aim is to develop detection techniques able to exploit the polarimetric information in order to improve the detection capability of ships or generally man-made targets modelled as extended targets (i.e. occupying multiple pixels). Both a decentralized and a centralized approach are considered for the fusion of the polarimetric information and their performance are characterized.

Exploiting the polarimetric information for the detection of ship targets in non-homogeneous SAR images

Ship detection in polarimetric SAR images of non-homogeneous sea areas is considered. We demonstrate the impact of non-homogeneous sea features on the false alarm rate and the need of extracting the image structure. We thus introduce polarimetric segmentation procedures that cooperate with high-resolution polarimetric detection features for the control of the false alarms. Different polarimetric segmentation-plus-detection procedures are tested over real data to devise the appropriate method to exploit the polarimetric information.

GPR for archaeological investigations: real performance assessment for different surface and subsurface conditions

This paper assesses GPR (Ground Penetrating Radar) performance for archaeological investigations. We exploit extensive data acquisition campaigns to characterize the instrument behavior in different operative conditions and we select ad hoc processing techniques to optimally extract target signatures from the collected data. The extensive analysis demonstrates the real effectiveness of GPR surveys in archaeological investigations.

Multi-sensor autonomous tracking for Maritime Surveillance

The fusion of multiple monitoring systems is essential to build an accurate recognised traffic picture in support to maritime surveillance. In this paper, a novel approach to perform autonomous data correlation is described, focussing on the alignment of tracks originated by different sensors and technologies into a common spatial and time reference system, and introducing the quality characterisation of the association process based on Bayesian inference. This is performed following the sensors uncertainties characterisation, the implementation of the tracks propagation concept and the influence of the scenario of interest calculation. The proposed algorithm represents a flexible solution to the problem of data fusion on multiple platforms, either ground-, air- and space-based.

Performance evaluation of radar detection schemes based on CA-CFAR against K-distributed clutter

An accurate analytical approximation is derived for the performance of the simple and widely used CA-CFAR detection schemes, when operating against K-distributed clutter. This compensates the absence in the literature of exact performance expressions for this well known type of disturbance. The proposed approximations are validated by Monte Carlo simulation to show their effectiveness.

Ship wake detection in SAR images: a segmentation-based approach

This paper deals with the derivation of a fully automatic and reliable ship wake detector (SWD), which can operate in conjunction with a ship detector scheme (SD) for ship traffic control against non-homogeneous sea background in SAR images. A novel segmentation-based technique is introduced for ship wake detection, which overcomes the drawbacks suffered by standard techniques operating in non-homogeneous background. This is composed of a preliminary segmentation stage to extract context information, followed by a modified wake detector. The new SWD scheme is shown to yield a large performance improvement on both simulated and real SAR data.

Decision support platforms for Satellite-Extended Vessel Traffic Services

The present work addresses the integration of satellite-based radar information into the operational process for recognized maritime picture (RMP) formation within maritime security applications. The concept of satellite-extended vessel traffic service (SEV) is illustrated and an efficient strategy for its implementation is here reported. Results from live test exercises are presented as (i) monitoring of sea borders, and (ii) monitoring of marine electronic highways. The two related decision support platforms are presented, for which the satellite-aided RMP plays a key role.