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Abstract. There is an increasing demand for high-resolution recording of in situ underwater cultural heritage. Reflectance transformation imaging (RTI) has a proven track record in terrestrial contexts for acquiring highresolution diagnostic data at small scales. The research presented here documents the first adaptation of RTI protocols to the subaquatic environment, with a scuba-deployable method designed around affordable off-the-shelf technologies. Underwater RTI (URTI) was used to capture detail from historic shipwrecks in both the Solent and the western Mediterranean. Results show that URTI can capture submillimeter levels of qualitative diagnostic detail from in situ archaeological material. In addition, this paper presents the results of experiments to explore the impact of turbidity on URTI. For this purpose, a prototype fixed-lighting semisubmersible RTI photography dome was constructed to allow collection of data under controlled conditions. The signal-to-noise data generated reveals that the RGB channels of underwater digital images captured in progressive turbidity degraded faster than URTI object geometry calculated from them. URTI is shown to be capable of providing analytically useful object-level detail in conditions that would render ordinary underwater photography of limited use.

Abstract:The use of terrestrial remote imaging techniques, specifically LiDAR (Light Detection And Ranging) and digital stereo-photogrammetry, are widely proven and accepted for the mapping of geological structure and monitoring of mass movements. The use of such technologies can be limited, however: LiDAR generally by the cost of acquisition, and stereo-photogrammetry by the tradeoff between possible resolution within the scene versus the spatial extent of the coverage. The objective of this research is to test a hybrid gigapixel photogrammetry method, and investigate optimal equipment configurations for use in mountainous terrain. The scope of the work included field testing at variable ranges, angles, resolutions, and in variable geological and climatologically settings. Original field work was carried out in Canada to test various lenses and cameras, and detailed field mapping excursions were conducted in Norway. The key findings of the research are example data generated by gigapixel photogrammetry, a detailed discussion on optimal photography equipment for gigapixel imaging, and implementations of the imaging possibilities for rockfall mapping. This paper represents a discussion about a new terrestrial 3-dimensional imaging technique. The findings of this research will directly benefit natural hazard mapping programs in which rockfall potential must be recorded and the use of standard 3-dimensional imaging techniques cannot be applied.

The determination of trace concentrations of the platinum group elements in gold bullion can be significant for establishing the geographical location from which the gold was mined. Platinum is of particular importance for ancient gold as a marker of provenance. While many techniques have been used successfully to quantify Pt in a nearly pure Au matrix, wavelength dispersive X-ray Fluorescence Spectrometry (WDXRF) has not yet been evaluated for this application. This paper demonstrates that Pt can be determined in gold coins with a limit of detection of 20 mg g À1 (k ¼ 3). Typical relative standard deviations were observed to range from 2% to 3% for Pt determined in gold coins (at 326 and 339 mg g À1 , respectively). The low bias created from the imprinted coin design raising the coin up (compared to a completely flat coin piece) was largely overcome by making a 50 mm trough in the sample cup to lower the coin relative to the X-ray tube to compensate for the coin design. Determined Pt concentrations on the side of the coin with the imprinted design were within +1 to À13% of the values obtained with the opposite side where the design was removed by polishing (measured in a normal sample cup) using the same XRF method. This method was deemed fit for purpose for historians wanting to track changes in Pt concentration in ancient Roman gold coins over long time intervals.

<p><strong>Abstract.</strong> High-end consumer quadcopter UAVs or so-called “prosumer devices”, have made inroads into the mapping industry over the past few years, arguably displacing more expensive purpose-built systems. In particular, the DJI Phantom series quadcopters, marketed primarily for videography, have shown considerable promise due to their relatively high-quality cameras. Camera pre-calibration has long been a part of the aerial photogrammetric workflow with calibration certificates being provided by operators for every project flown. Most UAV data, however, is processed today in Structure-from-Motion software where the calibration is generated “on-the-fly” from the same image-set being used for mapping. Often the scenes being mapped and their flight-plans are inappropriate for calibration as they do not have enough variation in altitude to produce a good focal-length solution, and do not have cross-strips to improve the estimation of the principal point. What we propose is a new type of flight-plan that can be run on highly textured scenes of varying height prior to mapping missions that will significantly improve the estimation of the interior orientation parameters and, as a consequence, improve the overall accuracy of projects undertaken with these sorts of UAV systems. We also note that embedded manufacturer camera profiles, which correct for distortion automatically, should be removed prior to all photogrammetric processing, something that is often overlooked as these profiles are not made visible to the end user in most image conversion software, particularly Adobe’s CameraRAW.</p>