In some application fields, such as underwater archaeology or marine biology, there is the need to collect three-dimensional, close-range data from objects that cannot be removed from their site. In particular, 3D imaging techniques are widely employed for close-range acquisitions in underwater environment. In this work we have compared in water two 3D imaging techniques based on active and passive approaches, respectively, and whole-field acquisition. The comparison is performed under poor visibility conditions, produced in the laboratory by suspending different quantities of clay in a water tank. For a fair comparison, a stereo configuration has been adopted for both the techniques, using the same setup, working distance, calibration, and objects. At the moment, the proposed setup is not suitable for real world applications, but it allowed us to conduct a preliminary analysis on the performances of the two techniques and to understand their capability to acquire 3D points in presence of turbidity. The performances have been evaluated in terms of accuracy and density of the acquired 3D points. Our results can be used as a reference for further comparisons in the analysis of other 3D techniques and algorithms.

In situ protection and conservation of the Underwater Cultural Heritage are now considered a primary choice by the scientific community to be preferred, when possible, over the practice of recovery. The conservation of the artefacts within their environmental context is essential in fact for a correct interpretation of archaeological presences and to preserve their true value intact for future generations. However, this is not an easy task because modern technological equipment is necessary to make the work carried out by underwater restorers and archaeologists faster and more efficient. To this end, the paper presents three innovative underwater power tools for the cleaning, conservation, and consolidation activities to be performed in submerged archaeological sites. The first one is an underwater cleaning brush tool for a soft cleaning of the underwater archaeological structures and artefacts; the second one is a multifunctional underwater hammer drill suitable to be used as a corer sampler, chisel, or drill; the last one is an injection tool specifically designed to dispense mortar underwater for consolidation techniques of submerged structures.

In this paper we present a methodology for the digitization, the survey and the visualization of a 3D model built from a large scale object that combines the use of different hardware, software and geometric data. The results are a detailed virtual model used for the documentation of the preservation status of the artifact and a simplified 3D model for the navigation with an immersive stereoscopic visualization system.

The Riace Bronzes represent one of the most important masterpieces of Magna Graecia archaeology, and of the whole world artistic heritage. The Bronzes, other than for their exquisite workmanship, are also interesting for the mysteries which surround their history. The countless hypotheses about their identity, origin and authors are supported by many studies of historical and iconographic nature. This paper describes a complete morphological study of the Riace Bronzes in order to provide to the archaeologists some objective data about the shape of the most interesting and controversial part of the Bronzes: the right hand of Bronzo “A”. This study aims to provide a series of geometrical data which could help to identify the object that the A Bronze was gripping. This questions is, in fact, one of the fundamental steps for the individuation of the Bronze A's identity.

Coralligenous bioconstructions are biogenic calcareous structures characterized by low accretion rate and high sensitivity to natural and anthropogenic impacts. Assessing their ecological quality and health status requires non-destructive approaches. In the project “FISR 2019_CRESCIBLUREEF”, a ROV-based coring device has been developed to collect samples while ensuring minimal impact on the ecological and structural integrity of bioconstructions and overcoming scuba diving depth and safety constraints. This study evaluates whether fragments retrieved by the device are representative of whole coralligenous build-ups (“tal-quale”) for geobiological characterization at the microscale. Representativeness is assessed through (i) preservation of microfacies textures and framework integrity in thin sections and (ii) relative abundances of skeletal and non-skeletal carbonate components quantified by point-counting. The results suggested that a coring device represents a powerful tool for obtaining representative bioconstruction samples at least in terms of the relationships and distribution between different carbonate components. This innovative approach opens new frontiers in the study of bioconstructed habitats, allowing the collection of samples suitable for qualitative and quantitative analyses while preserving ecosystem integrity. It therefore represents a step toward in sustainable marine research, with great potential for monitoring, conservation, and management of benthic habitats.