Developing Methods in High Resolution 3D Image Capture for Ancient Tablets

This summer I hope to provide updates on work being conducted by Kevin Pluta who is investigating and developing methods for reflectance transformation imaging (RTI), specifically tied to inscribed clay tablets.  His work, building off of work being done at the Oriental Institute, USC, and Leuven, will be mobile and require limited space, making the tools attractive for capturing data in a variety of contexts.  In addition to visible light, Pluta intends to investigate imaging in other spectra, resulting in a toolkit that will be portable and flexible for a variety of needs.  His work holds tremendous potential to the College of Charleston for increasing the research capabilities, undergraduate research opportunities, and servicing these opportunities to other researchers.  Combined with other informatic initiatives being drawn off the Avkat Project, Pluta’s imaging techniques have high potential for improving the informatics products under development at the College of Charleston.

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7 Responses to Developing Methods in High Resolution 3D Image Capture for Ancient Tablets

  1. Chris Gold says:

    This is great information about mobile caputre. Sounds like this is going to be a fun project.

  2. J. A. Evans says:

    There are many digital archaeology researchers using and developing methods in high-resolution 3D imaging, but the focus of the technology is not on RTI but close-range terrestrial LiDAR scanning (triangulation scanners) and structured-light scanners.

    How does Pluta’s RTI stack against these technologies?

    • Jim Newhard says:

      Great question! I’m hoping Dr. Pluta will jump in, as indeed, there are a variety of approaches. From the discussions I’ve had with him, RTI is one of several approaches to be investigated. Some of the factors include portability/mobility of the system, accuracy and resolution of the final image, the type of imagery captured (multispectral vs. panchromatic), ease of use and processing, and sensitivity to the artifact’s condition (many of these objects can be both irreplacable and extremely fragile). There are indeed many variables in the mix. RTI is well-used among many of our Near Eastern colleagues, and serves well as a jumping off point. More information will certainly follow as Kevin’s investigations progress.

      • Joe Evans says:

        I’m very interested in the results from analyzing these five factors. We are used to doing RTI in some very inhospitable places (jungles, deserts, steppes), but our setup is very crude and time consuming. Dr. Pluta’s system looks to be robust enough for our environs—possibly with slight modification—but overall it looks to be a great system.

    • Geoff Avern says:

      I would have thought that RTI is simpler, faster and cheaper than laser scanning (I hate the term “terrestrial LiDAR”). Yet it can give similar visual product (albeit from a fixed viewpoint) which can be very useful for qualitative assessment or interpretation, particuarly for coins and incised tablets. BTW, “terrestrial LiDAR” is a time-of-flight scanner, not a triangulation scanner, and are typically not accurate enough for modelling of clay tablets. Smaller triangulation scanners are.

      Personally, I’d be interested to know why the work with multispectral illumination. I wouldn’t have thought it very relevent to clay tablets.


      • Joe Evans says:

        Geoff, in our particular RTI setup, it was indeed cheaper than any of our laser scanners but I would hesitate to say that it is either (relatively) more “simple” or quicker than a laser scanner. It is most certainly more user-friendly, though. You’re correct—RTI is capable of delivering a similar visual product (through PTM) but depending on the project and the subject of investigation, it may not be enough. I know in our case we need the highly accurate metrics that terrestrial LiDAR scanning provides, but we also needing texture mapping, which is why we almost always combine the two.

        Actually, “terrestrial LiDAR” include any high-precision technology that utilizes lasers (or light) to measure distances to a target and image it. In the case of 3D laser scanners, terrestrial LiDAR isn’t limited to only the time-of-flight method and the scanners that utilize it (phase-shift scanners can collect up to 950,000 pps and produce insanely detailed pointclouds, for example) because there are many different methods of applying the LiDAR technology. Triangulation scanners, like ToF or P-S, still measure distance using lasers, so therefore they are still deemed terrestrial LiDAR (terrestrial LiDAR scanners). Also, phase-shift scanners are accurate enough (with the correct settings) to model small clay tablets and other artifacts.
        I am also very, very interested to see their results from multi-spectral illumination as well. I am hoping that it becomes a viable solution for an upcoming project.


      • John Wall says:

        Geoff and Joe,
        I cannot say for certain, but I think he is considering using multispectral data to ascertain the mineral composition of the tablets by using spectral libraries. One use of understanding mineral composition could be helpful in identifying clay sources by non-destructive means. Granted, there could be issues when referencing the spectral libraries due to the mixing of materials. At minimum, I would think signatures from each tablet could be compared thereby allowing us to see if tablets were made in a batch and, if so, which tablets in which batches.

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