Close Range Photogrammetry Applied to the Documentation of an Archaeological Site in Gaza Strip, Palestine

Abstract

Abstract. In a geopolitical very complex context as the Gaza Strip it has to be dealt with an enhancement of an archaeological site. This site is the monastery of St. Hilarion. To enable a cultural appropriation of a place with several identified phases of occupation must undertake extensive archaeological excavation. Excavate in this geographical area is to implement emergency excavations, so the aim of such a project can be questioned for each mission. Real estate pressure is also a motivating setting the documentation because the large population density does not allow systematic studies of underground before construction projects. This is also during the construction of a road that the site was discovered. Site dimensions are 150 m by 80 m. It is located on a sand dune, 300 m from the sea. To implement the survey, four different levels of detail have been defined for terrestrial photogrammetry. The first level elements are similar to objects, capitals, fragment of columns, tiles for example. Modeling of small objects requires the acquisition of very dense point clouds (density: 1 point / 1 mm on average). The object must then be a maximum area of the sensor of the camera, while retaining in the field of view a reference pattern for the scaling of the point cloud generated. The pictures are taken at a short distance from the object, using the images at full resolution. The main obstacle to the modeling of objects is the presence of noise partly due to the studied materials (sand, smooth rock), which do not favor the detection of points of interest quality. Pretreatments of the cloud will be achieved meticulously since the ouster of points on a surface of a small object results in the formation of a hole with a lack of information, useful to resulting mesh. Level 2 focuses on the stratigraphic units such as mosaics. The monastery of St. Hilarion identifies thirteen floors of which has been documented years ago by silver photographs, scanned later. Modeling of pavements is to obtain a three-dimensional model of the mosaic in particular to analyze the subsidence, which it may be subjected. The dense point cloud can go beyond by including the geometric shapes of the pavement. The calculation mesh using high-density point cloud colorization allows cloud sufficient to final rendering. Levels 3 and 4 will allow the survey and representation of loci and sectors. Their modeling can be done by colored mesh or textured by a generic pattern but also by geometric primitives. This method requires the segmentation simple geometrical elements and creates a surface geometry by analysis of the sample points. Statistical tools allow the extraction plans meet the requirements of the operator can monitor quantitatively the quality of the final rendering. Each level has constraints on the accuracy of survey and types of representation especially from the point clouds, which are detailed in the complete article.

Creation of a 3d Reference Model of an Archaeological Site From a Large Set of Ground and Uav Images

“…The Monastery of St. Hilarion is a major archaeological site located in the territory of the municipality of Nuseïrat in the Gaza Strip in the Palestinian Territory. The site is approximately 1.5 Ha in size and its main occupation is dated to the 4th century (Alby et al, 2013).…”

Heritage Education: Computational Design of the Virtual Exhibition at the Cultural and Scientific Divulgation Center of USP

“…Amorim e Groetelaars (2008) caracterizam o papel da fotogrametria como método relevante de documentação patrimonial que apresenta vantagens em relação às formas tradicionais de levantamento como, por exemplo, custos, rapidez, precisão e diversidade de produtos resultantes. Diferentemente de outras técnicas de aquisição 3D, a fotogrametria trabalha em múltiplas escalas com um dispositivo, sendo possível identificar objetos de diferentes dimensões, desde pequenos detalhes a edificações em ruínas e sítios arqueológicos (Alby et al 2013). Convencionalmente, o método mais popular e estudado para a documentação das heranças culturais é a fotogrametria de curta distância, caracterizada por Gruen et al (2008apud Shults, 2017) como de baixo custo.…”

Automatic Identification of Archaeological Artifacts on the Excavation Site

“…3D acquisition replaces drawing during excavation to document and record entire archaeological sites. The condition of a site can be preserved regardless of its evolution over time (Alby et al, 2013). The photogrammetric method saves time at the excavation site and reduces time-consuming activities while retaining quality information for the drawing (Alby, 2015).…”