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Differences between imaging techniques

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Hello, newbie here interested in RTI for an Palaeolithic project. Ive seen a few terms around, and one is multi spectrum imaging. What is the difference, if any, between this and RTI? Can anyone provide some information on the different techniques?


For lithics, as most are fairly small and portable, would making a dome be better? My knowledge base is fairly 'tabla Rasa' so simplicity in structure and lighting with great results is what I'm after for my initial research.


Thank you,


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Dear Rain,


RTI is a great technique for looking at fine details of the surface of objects.  It includes both color and shape information and lets you view that information in an interactive environment, which includes applying mathematical enhancements to the surface shape and/or color.  To learn more and see examples, you should check out the RTI page at Cultural Heritage Imaging: http://culturalheritageimaging.org/Technologies/RTI/


Since you are interested in lithics, I will also point you to Leszek's blog post and website about his use of RTI for lithics: https://culturalheritageimaging.wordpress.com/2015/06/30/using-rti-to-image-and-study-knapped-stone-tools/


Multi Spectral imaging uses different wavelengths of light to image objects.  This can include wavelengths outside of the visible spectrum, usually ultraviolet and infrared. In order to shoot images outside of visible light, you need a camera with a sensor that can detect those wavelengths.  There are a variety of options, including modifying a regular commercial SLR so that it can detect near UV and near IR wavelengths.  Then shooting those wavelengths requires either filtering the camera lens, or filtering the light to get the desired results.  Multi spectral imaging is used for a variety of situations.  For some material it doesn't show anything interesting. However, for some subjects, such as certain kinds of paintings, IR wavelengths can penetrate the outer surface of the painting, and a different layer of paint reflects back. This is totally dependent on the paints used, and which ones let that wavelength of light pass and which ones reflect back the light at that wavelength.  Multi spectral imaging can be combined with other types of imaging, such as RTI.  A very well done experiment with multi spectral bands and RTI was done by Todd Hanneken, and you can find his web site about the project here: http://palimpsest.stmarytx.edu/integrating/productsummary.html


Also of use to you might be the Glossary of photographic and technical terms for RTI - which includes definitions for multi spectral imaging: http://culturalheritageimaging.org/What_We_Offer/Downloads/Capture/CHI-RTI-Glossary_v1.pdf



Good luck with your project.



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