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In this paper, we report on an experimental activity aimed at investigating the potential of two terrestrial remote-sensing techniques, namely, ground-based SAR (GB SAR) interferometry and terrestrial laser scanning, in order to retrieve snow-depth (SD) measurements in mountainous regions. Terrestrial laser scanning is a more consolidated technique based on the measurement of the optical (near infrared) reflectivity, and it is affected by the surface of the snow layer: a temporal data sequence allows us to estimate the absolute SD variation. Recent use of SAR interferometry to evaluate snow-mass characteristics is based on relating the measured interferometric phase shift to a change in the snow mass. Interferometric GB SAR measurements and terrestrial laser scanner scans were collected together with pointwise conventional measurements of physical snow parameters during the winters of 2005/2006 and 2006/2007. The experiment was carried out in the Wattener Lizum, a high Alpine area at about 2000-m elevation north of the main ridge of the Austrian Alps in Tyrol. Notwithstanding the difficulty of providing both lengthy data record in dry snow conditions and detailed knowledge of the observed snow characteristics, the obtained results confirmed the presence of a clearly measurable interferometric phase variation in relation to the growing height of the snow layer. A comparison of the SD maps obtained through the two techniques shows differences partly due to the different nature of the two observations. Index Terms--Ground-based microwave interferometry, snow depth (SD), terrestrial laser scanner (TLS).

Remote dynamic monitoring of bridges by a high-speed interferometric radar is proposed. The equipment is a continuous-wave step-frequency radar with very fast frequency hopping that is capable of sampling the structure at a rate high enough for transient analysis of motion through phase comparison of successively acquired images. An experimental test carried out on a highway bridge forced by vehicular traffic is presented. Index Terms--Dynamic monitoring, interferometry, radar, remote sensing, structural test.

The alpine village of Lamosano, Belluno, Italy, located near a wide and active landslide, has been seriously threatened by ground instabilities since 1960. In this paper, the results obtained by two different remote-monitoring techniques, synthetic aperature radar interferometry and three-dimensional laser-scanner imaging, planned for Lamosano hazard assessment, are presented. Both techniques compare images taken at different times to map and classify changes that occurred on the imaged scenario. The radar and laser data are gathered at the same dates with about ten-month temporal separation. The displacements measured separately by each of the two techniques highlight a similar sliding motion on the Lamosano village area, providing a good validation to each other and contributing to the definition of the village instability hazard. Index Terms--Digital models, displacement fields, landslide monitoring, synthetic aperture radar (SAR) interferometry, terrestrial laser scanner (TLS).

Ground-based synthetic aperture radar (GB-SAR) interferometry has already been recognized as a powerful tool, complementary or alternative to spaceborne SAR interferometry, for terrain monitoring, and for detecting structural changes in buildings. It has been noted that, in spite of the very short range, compared with the satellite configuration, in GB-SAR measurement the disturbances due to atmospheric effects cannot be neglected either. The analysis of the interferometric phases of very coherent points, called permanent scatterers (PSs), allows the evaluation of the atmospheric disturbance and the possibility of removing it. In this paper, the PS analysis is carried out both on a test site facility and on a real campaign (Citrin Valley, Italy) that provided data with a temporal baseline of about ten months. Index Terms--Atmospheric effect, ground-based synthetic aperture radar (GB-SAR) interferometry, landslide monitoring, permanent scatterer (PS), radar.

The application of ground-based radar iterferometry for landslide monitoring is here analyzed: a case study based on an experimental campaign carried out in Italy in the year 2002 is discussed. Interferometric data obtained from coherent synthetic aperture radar (SAR) images acquired by means of C-band ground-based equipment ave analyzed. The campaign was aimed at retrieving potential terrain movements of a small landslide observed hundreds of meters away. Critical aspects related to spatial and temporal decorrelation ale discussed: the use of optical photogrammetry as a technique for evaluating mechanical stability and correcting geometric distortion is presented. Results also confirmed that the application of ground-based radar interferometry can be attractive and effective if the acquired SAR images maintain an adequate coherence on different dates. Index Terms--Decorrelation, differential interferometry, ground-based synthetic aperture radar, phase stability, synthetic aperture radar (SAR).

The acquisition process of the 3-D digital model of the Maddalena by Donatello, a wooden statue representing one of the major masterpieces of the Italian Renaissance, is described. The steps of the acquisition procedure, from the project planning to the solution of the various problems due to range camera calibration and to material non optically cooperative are presented.

Joint time-frequency analysis of penetrating radar response has been tested using simulated and experimental data as a processing tool for detecting stratified features inside a masonry structure. The radar response has been simulated exploiting the formalism of the propagators inside a finite number of dielectric layers. Experimental testing has been carried out by varying the thickness of the hollow space between two walls. Index Terms--Continuous wave step frequency (CW-SF), joint time-frequency analysis (JTFA), microwave, nondestructive testing, radar.

The generation of three-dimensional (3-D) digital models produced by optical technologies in some cases involves metric errors. This happens when small high-resolution 3-D images are assembled together in order to model a large object. In some applications, as for example 3-D modeling of Cultural Heritage, the problem of metric accuracy is a major issue and no methods are currently available for enhancing it. In this paper the authors present a procedure by which the metric reliability of the 3-D model, obtained through iterative alignments of many range maps, can be guaranteed to a known acceptable level. The goal is the integration of the 3-D range camera system with a close range digital photogrammetry technique. The basic idea is to generate a global coordinate system determined by the digital photogrammetric procedure, measuring the spatial coordinates of optical targets placed around the object to be modeled. Such coordinates, set as reference points, allow the proper rigid motion of few key range maps, including a portion of the targets, in the global reference system defined by photogrammetry. The other 3-D images are normally aligned around these locked images with usual iterative algorithms. Experimental results on a anthropomorphic test object, comparing the conventional and the proposed alignment method, are finally reported. Index Terms--Error analysis, measurement accuracy, shape measurement, 3-D modeling.

In this paper, the authors propose an innovative survey radar technique based on microwave holographic images for dynamic testing of large structures providing both vibration amplitude pattern and frequency. Theoretical background is provided and experimental results obtained during a dynamic test on a concrete and masonry building are reported. Index Terms--Large structure, microwave, nondestructive testing, radar, remote monitoring.

The serial performance of 64-point fast Fourier transform of Doppler echoes allows an ultrasound multigate system to accurately determine velocity profiles. The echoes have their origin in 64 investigated range cells. The system can provide about 50 velocity profiles per second. All information is obtained by high-resolution A/D converters and is processed using digital circuits. Each spectrum is processed and significant parameters are calculated. The determination of maximum frequency allows highly accurate velocity profiles.

Experiments on a thread phantom reveal that spectral analysis can be used to calculate transverse velocity vector amplitude and direction. The simultaneous use of two focused transducers permits velocity vector determination in three dimensional space. The flow line distance from the transducer does not affect Doppler spectrum width. An efficient spectrum analyzer, capable of exact and reproducible bandwidth measurement, is essential for transverse Doppler studies.

In this paper, the authors propose a ground-based interferometric synthetic aperture radar (SAR) technique for terrain mapping. It is based on a coherent continuos-wave step-frequency (CW-SF) radar moved along a linear horizontal rail. It works synthesising microwave holographic images taken from different points of view to obtain elevation maps by phase comparison. The focusing algorithm for imaging synthetic holograms and digital elevation models (DEM) is able to correct topographic distortion and phase wrap through an iterative multi-baseline procedure. Index Terms--Digital elevation model (DEM), interferometry, synthetic aperture radar (SAR).

The Modern habitats of Morocco and Algeria are an interesting metaphor of the structured, rich and dramatic comparison between the different cultures on the two sides of the Mediterranean sea. This study recognises the complexities and intrinsic qualities contained in the original plans of the most significant masshousing projects of the 1950s-1960s in Casablanca and Algiers, outlining the main processes of continuous transformation and adaptation between the individual and collective spheres. The tension between living and settlement models, product of an "enlightened rationalism" (but nonetheless authoritarian) and the tumultuous process of appropriation of the colonial peripheries by new social players that reinterpret them to their extent, constitutes an extremely interesting field of analysis and design. [ABSTRACT FROM AUTHOR]

This research investigates the effectiveness of Brandi's ‘uniqueness of method' principle for the preservation of multi-layered archaeological landscapes, with particular reference to coastal defence systems in urban area. These are strategic places for the defence of historic settlements that are characterized by the persistence of military use from the old age until modern times. The enhancement of these places goes through the integrated knowledge of the artefacts and the deep understanding of mutual contextual relationships at the different scales of analysis - historical, material, architectural, stratigraphic, conservative - in order to generate design projects compatible with the preservation of historical and testimonial values. The paper illustrates the results of integrated scientific investigations and educational programmes conducted on the archaeological defensive area of the Sant'Ignazio fort in Cagliari, built between 1783 and 1798 but never put into service. Reversible and recognizable functional addictions have been designed, interpreting the memory-space-matter triad. These reading deals with Heritage in a contemporary view, according to the idea of continuity in the historical process and confirming the potential of the formal principles of the overlap, integration, support and suspension. [ABSTRACT FROM AUTHOR]