**1. Introduction**

This chapter focuses a new visualization approach to the monitoring of internal microdiscontinuities such as cracks, micro-fractures and cavities, and archaeological remains with foundational infrastructure. The method uses a hybrid interactive two-dimensional / threedimensional (2D/3D) transparent visualization of ground penetrating radar (GPR) data set gathered from sites of archaeological and cultural heritage. The data visualization is based on methodological formulation of amplitude–colour scale function for 2D radargram visualiza‐ tion to indicate micro-discontinuities, infrastructures and buried archaeological remains. The transparent 3D imaging combines to half bird's-eye view was constructed from a processed parallel-aligned 2D GPR profile data set by using an opaque approximation instead of linear opacity. The amplitude–colour scale is balanced by the amplitude range of the buried remains within a proposed depth range, and appointed an opaque coefficient in order to differentiate buried remains from others. Interactive visualizations are conducted of transparent 3D half bird's-eye view of GPR data volumes.

Archaeological and cultural heritage represent cultural identity and a source of creativity for present and future generations. Conservation of art treasures is a serious problem, since all objects change or deteriorate over time, mainly due to natural forces of decay. Requirements for maintaining the existing condition of buildings, monuments or statues of historical interest differ from the requirements of an initial treatment. Many of the problems associated with treatment involve the lack of prior, baseline information. Identification of the causes of degradation and understanding of the cause/effect relationships are crucial for the conserva‐ tion of archaeological and cultural heritage. The treatment of such items generally involves

© 2013 Kadioglu; licensee InTech. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2013 Kadioglu; licensee InTech. This is a paper distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

coating or vapour barriers, and compatibility with substrate. However, cultural heritage requires maintenance not only for its walls, but also its infrastructures and security of foun‐ dations. Therefore, safety and maintenance management of such sites must include imaging of infrastructures and potential discontinuities. The same importance should be given to archaeological sites, especially in urban areas. Therefore, there is also a need for improved non-invasive methods of visualization in evaluating the progress of the buried infrastructures of archaeological heritage.

cy and reveal the fractures, cavities, buried wall remains and foundational infrastructures of

Transparent 2d/3d Half Bird's-Eye View of Ground Penetrating Radar Data Set in Archaeology and Cultural Heritage

http://dx.doi.org/10.5772/54998

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In this chapter, first, the method was used to show micro-discontinuities in monumental statue groups at Mustafa Kemal ATATÜRK's mausoleum (ANITKABIR) in Ankara, Turkey. Second, the method was used to define buried infrastructures and archaeological remains inside and northeast of the Zeynel Bey tomb, in Hasankeyf ancient city in south-eastern Turkey. The studies examined whether the proposed GPR method could yield useful results at these highly restricted sites. Our visualization results were an interpretation of the two datasets with

The Anitkabir mausoleum, was completed in 1953 in Ankara, Turkey (Figure 1). It hosts state ceremonies during national festivals, and represents the Turkish people and Ghazi Mustafa Kemal ATATÜRK, the founder of the Republic of Turkey (Figure 1b). Anitkabir was con‐ structed in three phases. The first part is an entrance road, called the Lion Road, which is 262m long and has a total of 24 lion statues along each side, representing power and peace (Figure 1c). The second part is a ceremonial square, and the third is the Mausoleum (Figure 1c). At the beginning of the Lion Road, the Turkish people are represented by three large male statues in front of the Freedom Tower on the left side (Figure 1d), and three large female statues in front

The monument groups (three women, three men) and twenty-four lion statues of Anitkabir are mainly composed of white travertine from Pinarbasi, Kayseri, Turkey. The white-coloured travertine has a banded and spongy texture under the microscope [23]. It is mainly composed of calcite, aragonite with a small amount of salt, recrystallized calcite, gypsum and plant relicts. Table 1 shows the modal mineralogical composition and physical properties of this travertine. Micro-fractures were observed under a polarizing microscope, especially at the rim of the

**Alteration Products** Recrystallized calcite (13.5) and rarely gypsum and halite (1.5%)

**Table 1.** Mineralogical composition and physical properties of white-coloured travertine in Anitkabir.

interest. The fourth and fifth steps are conducted one within the other.

**2. Monitoring micro-discontinuities in monumental statues**

**2.1. Study area: Mustafa Kemal ATATURK'S Mausoleum, ANITKABIR**

of the Independence Tower (Figure 1e) on the right side [29].

**Mineral Composition** Calcite (54%) and Aragonite (31%)

vesicular of the rocks (Figure 2).

**Colour** White

**Unit Volume Weight** 2.52 gr/cm3 **Porosity Ratio (%)** 9.8 ± 2.180 **Cracks Ration (%)** 3.4 **Alteration Ratio (%)** 2.5

**Hardness** 3 Mohs, 52.8 Schmidt

different objectives.

Ground penetrating radar (GPR), which is also called surface penetrating radar, is a timedependent, high frequency electromagnetic geophysical technique that can provide a 3D pseudo image of the subsurface, including the fourth dimension of colour, and can also provide accurate depth estimates for many common subsurface objects [1, 2]. GPR uses the scattered wave field of high frequency electromagnetic (EM) waves. The EM waves travel at a specific velocity that is determined primarily by the permittivity of the material. The principles of GPR have been explained extensively in the literature [3], especially for fault and fracture imaging [4-9]; in assisting contaminated sites by locating buried features of interest such as under‐ ground storage tanks, pipes [10-11], unexploded ordnance (UXO) and clutter [12-14]; and in the mapping of shallow stratigraphy and discontinuities [3, 15-20].

Ground penetrating radar (GPR) provides more detailed results than other geophysical methods, because it can image the position and the depth of targets within very complex and restricted areas. The method is non-destructive and can be applied on a surface, a wall, or a monument [21-23]. The method can also be used in urban areas or in archaeological structures and, depending on the antennas and the particular situation, can achieve a resolution of the order of several centimetres 24-26]. Therefore, it has been the most commonly used method for defining cultural heritage and buried remains at archaeological sites. Furthermore, detailed imaging has become an important area of interest [1, 24- 28]. Generally, parallel 2D profile data are acquired in the archaeological site. 3D data imaging, obtained by aligning parallel 2D profile data sets, is used to identify temporal changes at a constant depth. The locations and the depth of the remains in the study area can be determined via slices of the 3D data volume. Therefore, the GPR method gives more precise results than other geophysical methods. However, the obtained results and their interpretation can be further improved when the data set is visualized as a volumetric rendering of the remains. This method allows anyone to imagine how an area looked by looking into the 3D image.

The aim of this chapter is to show transparent 3D GPR data visualization with the most suitable viewing angle into this 3D data volume including buried objects, which is called a transpar‐ ent 3D half bird's-eye view of the GPR data volume or its sub-volumes. Therefore, first, we introduce the study areas and data acquisition,followed by general data processing steps ofthe gathered 2D GPR profile data set. Third, we show a revised colour range of the amplitude scale, representing the fourth dimension of the hybrid 2D/3D visualization. Fourth, we attempted to realize a new amplitude–colour-balancing approximation, according to the travel time range ordepthrange,asanalternativeapproximationofgaininordertopreventexaggeratedamplitude gain,whichaffects transparencyandobscuresburiedinfrastructures.Fifth,we appointedanew opaque function, which must support amplitude–colour scale in order to supply transparen‐ cy and reveal the fractures, cavities, buried wall remains and foundational infrastructures of interest. The fourth and fifth steps are conducted one within the other.

In this chapter, first, the method was used to show micro-discontinuities in monumental statue groups at Mustafa Kemal ATATÜRK's mausoleum (ANITKABIR) in Ankara, Turkey. Second, the method was used to define buried infrastructures and archaeological remains inside and northeast of the Zeynel Bey tomb, in Hasankeyf ancient city in south-eastern Turkey. The studies examined whether the proposed GPR method could yield useful results at these highly restricted sites. Our visualization results were an interpretation of the two datasets with different objectives.
