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Table 1 Summary of methods and technologies used for this study with expected outcomes

From: Application of multi-modal 2D and 3D imaging and analytical techniques to document and examine coins on the example of two Roman silver denarii

Method Sensor/analytical tools used Expected data outcome Conclusions
Photography DSLR (Nikon D200) Digital images = pixel-data Appearance of the coin, text and image, corrosion, etc.
Focus-stacking DSLR Canon EOS 600D + Cognisys Stackshot
Digital microscopy Hirox KH-7700
Digital images = pixel-data, 3D surface geometry Surface image in high-resolution and high depth of field, imagery with high photographic detail
Digital microscopy Digital microscopy Hirox KH-7700 Same as above Same as above
Dome-photography/PTM/RTI DSLR camera in nadir position + lights (flash or LED lights) in a half-dome, four arrangements used in this research Raw digital image data and colour calibrated images according to camera/lens/resolution Surface visualisation with interactive lighting of near-flat objects, no 3D information
Photometric stereo Same as above, (machine vision) camera and robotic light with rotation table in dark space Same as above + coloured surface geometry 3D surface geometry for near-flat objects (in colour) at high detail
Photogrammetry and SfM DSLR + lights Raw digital image data, colour calibrated images, 3D surface point cloud, 3D surface model Surface geometry in 3D and surface colour
3D scanning 3D laser scanner (IDENTIK 300L Arius Technology Scanner, Micro-Epsilon, NextEngine), 3D structured light scanner (MechScan 3D Macro, SmartSCAN HE with 8MP stereo cameras) (complemented by analytical balance) Same as above; volume [cm3], plus in combination with the analytical balance weight: density [g/cm3] Surface geometry in 3D and surface colour; determination of volume, material composition estimation due to known material densities
microCT Microtomograph Nanotom 180 (GE Phoenix), measurement conditions X-ray images Internal structure, rendered 3D model, film of slices (link to Additional files 1, 2, 3, 4)
SEM/EDX SEM (JEOL JSM 7600F) coupled with EDX Elemental spectra with characteristic peaks, tables of elemental % per sampling area, 3D Image of the surface, elemental analysis to 15 μm surface depth Elemental analysis of coins, elemental matrix maps of surface, surface image with 3D visualisation
XRF ARTAX 200, ARTAX 800, S1 Titan handheld XRF spectrometer (Bruker) Elemental spectra with elemental analysis to 150 μm surface depth Surface chemistry of the coin, multi-elemental analysis
Gas pycnometry Pycnometer Micrometrics AccuPyc II 1340 (complemented by analytical balance) Volume [cm3], plus in combination with the analytical balance weight: density [g/cm3] Determination of volume, material composition estimation due to known material densities
Analytical balance Kern, Sartorius B120S Weight [g] Same as above