F. Menna

A Multi-Resolution Methodology for the 3D Modeling of Large and Complex Archeological Areas

This article reports on a multi-resolution and multi-sensor approach developed for the accurate and detailed 3D modeling of the entire Roman Forum in Pompei, Italy. The archaeological area, approximately 150 × 80 m, contains more than 350 finds spread all over the forum as well as larger mural structures of previous buildings and temples. The interdisciplinary 3D modeling work consists of a multi-scale image- and range-based digital documentation method developed to fulfill all the surveying and archaeological needs and exploit all the intrinsic potentialities of the actual 3D modeling techniques. The data resolution spans from a few decimeters down to few millimeters. The employed surveying methodologies have pros and cons which will be addressed and discussed. The results of the integration of the different 3D data in seamlessly textured 3D model are finally presented and discussed.

Dense image matching: Comparisons and analyses

The paper presents a critical review and analysis of dense image matching algorithms. The analyzed algorithms stay in the commercial as well open-source domains. The employed datasets include scenes pictured in terrestrial and aerial blocks, acquired with convergent and parallel-axis images and different scales. Geometric analyses are reported, comparing the dense point clouds with ground truth data.

Gas-Drone: Portable gas sensing system on UAVs for gas leakage localization

Volatile chemical concentration and gas leakage recognition can be crucial in environmental monitoring for risk assessment. The use of Unmanned Aerial Vehicles (UAVs) to measure spatially distributed gas concentration is of great interest because it allows a Simultaneous Localization And Mapping (SLAM) of the volatiles. This field is quite recent and, so far, few efforts have been dedicated to the design of integrated sensing instruments that focus on the optimization of crucial features as weight, dimension and energy autonomy, as important as selectivity and sensitivity of sensors on board UAVs. The proposed Gas Sensing System (GSS) is a fully autonomous board based on a 32bit MCU with 30min autonomy (on its own battery), data storing, wireless connectivity for real-time feedback and embeds a custom micro-machined MOX (Metal Oxide) sensor. This system can be mounted on any UAV thanks to its small dimensions and light weight. Experiments demonstrate that the sensing performance is not impaired by the air flow during the flight and we are able to spatially describe the volatile concentration.

3D modeling of large and complex site using multi-sensor integration and multi-resolution data

The article describes a multi-resolution approach developed for the 3D modeling of the entire Roman Forum in Pompeii, Italy. The archaeological area, approximately 150 x 80 m, contains more than 350 finds spread all over the Forum as well as larger mural structures of previous buildings and temples. The interdisciplinary 3D modeling work consists of a multi-scale image- and range-based digital documentation method developed to fulfil all the surveying and archaeological needs and exploit all the potentialities of the actual 3D modeling techniques. Datas resolution spans from few decimetres down to few millimetres, both in geometry and texture. The employed surveying methodologies have pros and cons which will be addressed and discussed. The first results of the integration of the different 3D data in a unique and seamless textured 3D model will be presented.

Design and implement a reality-based 3D digitisation and modelling project

3D digitisation denotes the process of describing parts of our physical world through finite measurements and representations that can be processed and visualised with a computer system. Reality-based 3D digitisation is essential for the documentation, conservation and preservation of our Cultural Heritage. This article composes a critical review of the digitisation pipeline, ranging from sensor selection and planning to data acquisition, processing and visualisation.

Geometric and Optic Characterization of a Hemispherical Dome Port for Underwater Photogrammetry

The popularity of automatic photogrammetric techniques has promoted many experiments in underwater scenarios leading to quite impressive visual results, even by non-experts. Despite these achievements, a deep understanding of camera and lens behaviors as well as optical phenomena involved in underwater operations is fundamental to better plan field campaigns and anticipate the achievable results. The paper presents a geometric investigation of a consumer grade underwater camera housing, manufactured by NiMAR and equipped with a 7′′ dome port. After a review of flat and dome ports, the work analyzes, using simulations and real experiments, the main optical phenomena involved when operating a camera underwater. Specific aspects which deal with photogrammetric acquisitions are considered with some tests in laboratory and in a swimming pool. Results and considerations are shown and commented.

GNSS/INS aided precise re-photographing

Re-photographing is a well-established method of acquiring new images in the same location where old photos were taken, in order to visualize changes and evolutions of the analyzed scene. According to the goal of the re-photographing procedure, different techniques can be employed, mainly based on visual methods, image cues or positioning sensors. The paper, after a review of the re-photographing procedures and techniques, presents a GNSS/INS aided method to achieve precise re-photographing results. Architectural and natural scenarios are used to test the developed method.

Photogrammetry of the Human Brain: A Novel Method for Three-Dimensional Quantitative Exploration of the Structural Connectivity in Neurosurgery and Neurosciences

BACKGROUND Anatomic awareness of the structural connectivity of the brain is mandatory for neurosurgeons, to select the most effective approaches for brain resections. Although standard microdissection is a validated technique to investigate the different white matter (WM) pathways and to verify the results of tractography, the possibility of interactive exploration of the specimens and reliable acquisition of quantitative information has not been described. Photogrammetry is a well-established technique allowing an accurate metrology on highly defined three-dimensional (3D) models. The aim of this work is to propose the application of the photogrammetric technique for supporting the 3D exploration and the quantitative analysis on the cerebral WM connectivity. METHODS The main perisylvian pathways, including the superior longitudinal fascicle and the arcuate fascicle were exposed using the Klingler technique. The photogrammetric acquisition followed each dissection step. The point clouds were registered to a reference magnetic resonance image of the specimen. All the acquisitions were coregistered into an open-source model. RESULTS We analyzed 5 steps, including the cortical surface, the short intergyral fibers, the indirect posterior and anterior superior longitudinal fascicle, and the arcuate fascicle. The coregistration between the magnetic resonance imaging mesh and the point clouds models was highly accurate. Multiple measures of distances between specific cortical landmarks and WM tracts were collected on the photogrammetric model. CONCLUSIONS Photogrammetry allows an accurate 3D reproduction of WM anatomy and the acquisition of unlimited quantitative data directly on the real specimen during the postdissection analysis. These results open many new promising neuroscientific and educational perspectives and also optimize the quality of neurosurgical treatments.