I am a scientist who utilizes multispectral imaging to recover and preserve information from old documents. AMA!

What was the (persumabely) oldest document you ever recovered?

I know my colleagues have worked on the Dead Sea Scrolls, which I'm pretty sure are as old as they come. But personally, the Archimedes Palimpsest is the oldest document I've worked on.

I'm new to this whole world and gave both The Dead Sea Scrolls and Archimedes Palimpsest a Google. Your job is the coolest ever and so is this AMA. Can you ELI5 the findings on both of those?

Wow thank you! While I'm not sure of the significance of the findings for the Dead Sea Scrolls or the Archimedes (in terms of history, culture, or the translations), I do know that so far, there have been many successful recoveries on both documents. I am not literate in the languages of the text I try to reveal, so unfortunately I can't read as I go, I pass along my data to the experts who can.

Getting successful recoveries is the best outcome because:

1) The information is now preserved digitally and won't fade over time, so it can be studied for an indefinite period of time.

2) We are able to reveal text that hasn't been looked at in over 2000 years... We hope that the text is significant in terms of it's content, and if it is, it can literally change what we know about our world's history.

That makes total sense! So you just focus in on the actual process of uncovering the info, not the analysis?

In that case, I have another question! Was there ever a document you were working on that completely infatuated your interest outside of the technical details of uncovering hidden text? Like, a piece of history that really interested you in all ways?

For example, if I had your job (and obvious vast amount of knowledge, kudos for that btw) I'd be all over Egyptian scrolls. That shit just rings my interest

Yeah, in other words, I really just try to provide useful images to those who can read and make sense of the information.

Yes, absolutely. The Martellus Map really grabbed my attention, and I was pretty desperate to start working on it. I bugged my advisor for a very long time before I started working with him. And while I know there are millions of people who know more about history and maps than I do, I think it's so interesting to learn first-hand what the educated people in the 15th century thought about the world.

Scattered all around the map are these legends and cartouches which contain text that very briefly describe the land there. They can be pretty funny to us now, but it's really interesting to see how our knowledge of the world progressed to what it is now.

Digital information doesnt fade but formats/filesystems change so rapidly that you can quickly find yourself without any data that is readable. https://en.wikipedia.org/wiki/Digital_dark_age

On top of storing our images in multiple file formats, uncompressed and compressed, we store copies of them in multiple places! I don't think that we are concerned about not being able to read them.

As a historian studying Christianity, I can definitely say the Dead Sea Scrolls are extremely important for understanding the development of language and also providing the earliest known copies of the Hebrew Bible. This allows for a better reading of the Bible today because we can take direct translations of the earliest known text rather than having translations of translations of translations. In the case of the King James Bible written in 1611, the first prominent and widespread English Bible, it was translated from Hebrew into Aramaic (possibly into Coptic, a language that developed between Egyptian hieroglyphs and its modern alphabet) into Latin and finally into English. And if you've ever played the translation game, words and meaning of sayings can get seriously messed up. That is the significance for at least the Dead Sea Scrolls! I would love to know about the other one if anyone knows!

Also, love to add that this is really cool to see someone who works on the other side of me. As a historian/research librarian I work with the documents and preserve them as much as possible in temp controlled rooms and such, but never really get to meet the guys saving and digitizing the documents for us! Currently working on my masters in medieval history but I hope to learn more about your field while working as a Rare Books and Manuscripts curator. Do you have any advice for me?

Please check out the links I provided in the original post! If you're more curious about the Imaging Science side of things, please look at Roger Easton's page and the CIS website. You may also be able to connect with other researchers in the same discipline as yourself if you connect with the researchers mentioned in the Martellus or Archimedes articles! Best of luck to you!

Microsoft Word crashed and none of my documents saved. Is there anything you can do to recover them?

Just kidding, Kevin. Thanks for doing an AMA! In your estimation, is the image science research community working at a sufficient rate to preserve our great libraries before the books are inevitably lost? How much longer do the Martellus Map of 1491 and other artifacts like it stand to survive in their present cozy, climate-controlled environments?

Thanks for the question!

Well, considering the amount of text that was lost on the Martellus in the 500 years since it was painted, and also considering the fact that the documents that many people want imaged are much, much older than 500 years old, we need to act as soon as we can to try to preserve as much as possible.

In my opinion, I think not. We need a larger community working on this type of research. The imaging science community is surprisingly small considering its applications in almost every other field in the world. While that kind of job security should make me happy, it actually worries me that we aren't putting enough resources into preserving our history and culture when it's sitting in museums doing nothing but deteriorating.

Gotcha, that was my concern that there'd be too few scholars going into the field. All the better reason to do an AMA!

Has Google been of any help with delicate works? I know their main effort has been more of a feed-into-a-machine-and-go, but they could do wonders with their ability to charge forward on a project and make the information so widely accessible.

Yeah, at first when I got requests for an AMA, I kind of laughed to myself. But after thinking about it a little, I decided to do it with the off-chance that someone with influence sees and decides to act.

I'm not aware of the efforts Google is making in this field, but I'm sure they have their chip in the dip (Is that a saying? I don't know. Maybe I just made something up.) as they so often do.

That being said, Google translate has been super helpful to me working in the lab, to help me figure out if the words I recover mean anything!

Are there any dangers involved during the processing of ancient manuscripts? Could a misstep lead to a portion of a text being lost, and has this ever happened?

Yes there is significant risk in removing some of the documents from their casing and exposing them to intense light. However, my group is very conscientious about how we expose the target. Previous imaging teams used broad-spectrum light which exposed the targets to way more light than they should have, and that resulted in heat transfer and the loss of ink/pigment.

We use LED light sources which emit a very narrow bandpass, which dramatically reduces the light energy incident upon the target to the point where there is almost no risk.

I can't imagine a job where I could get fired for turning the lights on too bright... What's the worst thing you'll admit to screwing up?

This AMA is great, btw. ^{100 times better than Hilary Duff's} I'm captivated by such an obscure branch of science.

Well, I've honestly been quite good about not screwing things up. The worst I've done so far is forget which hard drive (of like 80 4TB hard drives that surround me) I stored my data on. So, I had to start over, which is fine, but all that data took some time to process again.

Wow. Move over Hillary Duff. I'll be stealing the spotlight today. Thank you so much! To have so many people ask me questions about the stuff I spend so much time doing is actually really nice!

How accurate was National Treasure I and II, and why were they very accurate?

Not accurate. They had a very whimsical interpretation of document imaging techniques. Great movies though.

Would you consider National Treasure the Jurassic Park or Indiana Jones of your career?

Also on a related and more serious note, do you consider yourself an archaeologist? You are in essence recovering ancient artifacts for the study of cultures past, even if your methods of excavating and far from traditional.

I'd love to haphazardly travel across the world uncovering the dark secrets of history, so I'd totally try National Treasure out. I'm afraid of dinosaurs, loved the new movie, but I'll have to say no to dinosaurs. My boss is Indiana Jones, so I can't.

I don't consider myself an archaeologist, I don't actually uncover the documents. I am proud to be part of a team who leads an effort into preserving cultural heritage! But I think the more scholarly colleagues of mine are more suited to the title of archaeologist.

Can you walk us through the general practices of finding the overwritten text?

Well, we capture high-resolution, narrow-band multispectral imagery using tunable LED light sources and color filter wheels in combination with our multispectral camera.

We then take our massive data products into ENVI, a software package from Exelis Inc., which is very useful for image processing. Usually used for Remote Sensing purposes, ENVI also contains statistical processing routines that are invaluable for our research task too!

Within ENVI, we simply use combinations of statistical processing routines, like Principal Component Analysis, Independent Component Analysis, and spectral math to generate imagery whose contents are visually enhanced.

Can you talk a little more about these instruments? Makes and models. Just curious to see the equipment.

I'm not positive of the model (maybe the EV?), but check out MegaVision! MegaVision -- Cultural Heritage Division

We most often use a MegaVision multispectral camera for our imaging, mainly because we have a colleague who works for them, but also because their equipment is top!

Oh, that's pretty cool. I actually worked on a competitor's multispectral & hyperspectral image processing tools for remote sensing about a decade ago. I'd like to second a request for more info on the hardware and frequencies used since I only really worked with the software end.

The wavelengths of light we capture at are 365 to 940 nanometers in steps of ~50nm. Then we perform fluorescent ultraviolet imaging, which uses ultraviolet light, but not at specific wavelengths.

Like this?

basically.

what file format do you store the images in? Something standard (TIF, PDF) or something proprietary?

If it's anything like the radiation imaging results I've worked with, it's nothing like the examples you gave. They are not even "proprietary" per say, they are just not even really "images" in the traditional sense of the word - rather, they are voltmeter readings from the detectors, that are later processed (into something that is really closest to Raw images).

No, they are images in the way everyone is familiar with! We capture digital RAWs and process them! They aren't your every day 8-bit images though. We capture 12-bit images, so our digital count values range between 0 and 4096 instead of 0 to 255! A higher dynamic range is incredibly useful for our statistical processing!

We store the images in multiple file formats, tiffs because they are lossless, jpegs because they can be convenient for viewing, PDFs for use in documents and articles, and finally, .img files for working in ENVI.

This needs more votes; if we're exposing the document to air, even slightly like OP, then the results should be in open data otherwise they are at even greater risk of being lost to time.

I'm all for open-source, free, available data! I wish it was my call to make. However, I'm pretty sure that one of our main goals is to publish the original images as well as our processed images for the general public and for scholars to be able to research the documents as well.

I think you can expect to see our data available in the future.

Has there ever been anything surprising you've come across while imaging documents?

Yes, the craziest thing is when you find an entire layer of text below text you can see clearly. It makes you wonder all sorts of things about the limitations of our human visual system, and that there is much more than meets the eye.

What has been your most interesting find so far?

Cartouches are treasure troves of hidden text. On the Martellus map, I've found text in small sections of the map where there was thought to be no text (or no recoverable text). Written in these cartouches are some pretty interesting passages by Martellus himself.

Congratulations on your scholarship, it is certainly a fascinating pursuit. Why can't you disclose your work?

Thank you!

Well... funding for our research is typically from private donors, museums, and, in the case of remote sensing, the government or government contractors. While maybe it's okay to show you guys stuff, I wouldn't take a chance disclosing any of my work that could result in some legal shitstorm that could affect my career or the careers of my friends who I work with.

How was the original writing in these old documents erased? Was it painted over or some such?

Many times the ink was washed off with water or chemicals, other times the ink was scraped off. Then, the cleaned paper is reused and written/painted over. Otherwise, the text is faint due to natural aging and fading of pigments.

From the RIT website about imaging science:

"If we can remotely probe the structure and nature of an object, we can make an image of it and use that image to develop human comprehension."

Sounds amazing. What inspired you to want to study imaging science? How did you end up where you are?

Long story, I changed my major a handful of times (even before arriving at R.I.T) from International Business, Physics, Film & Animation, and finally Imaging Science.

I knew I wanted to study math and physics, but I wanted a specialized curriculum, so I looked into Imaging Science because I had the connection with the Film & Animation program.

I attended a presentation given by a PhD student who worked on the palimpsest research project, and it was so interesting that I decided to switch. And I switched my first week of freshman year and have loved it since.

So you switched from business into physics and eventually imaging science? You give me hope that wall street is yet not able to steal away all of the best minds. Good on you, you are doing great work and setting an example for other able minds. Having studied physics and seen many of my colleagues end up as quants on wall street, I am always happy to see someone using his brain for advancing knowledge, instead of trying to game the financial markets.

Yeah, I've thought a lot about what it meant to switch my major so drastically, and the career paths that open up (and close) by doing so, and to be summarized simply:

I ended up here because I'm studying something I genuinely think is interesting, something that I can do for a career that can help others, the people around me every day are amazing, and I'm happy where I am in life. I think as long as those remain true, I can accomplish what I want to.

So, when you are imaging a document, are you capturing reflective photons, transmissive, or both? Are you looking for florescence in any of the target materials?

All of the above. We capture transmissive, reflective, and fluorescence from both sides of the parchment. We have images of both sides because sometimes, the ink can stain through the layers and not fade as much as the surface layer.

Do you use anything above UV or below IR to reveal pigments that can't be seen using the EM spectrum?

I'm not sure if I understand your question entirely, as we can only use the EM spectrum to capture digital images.

We don't usually go below IR for any reason, but sometimes, a document may be a good candidate for X-Ray Fluorescence Imaging, which, as you can imagine, uses x-rays to generate images.

Whats the 'coolest' peace you have worked with / worked on ?

I love maps, I get lost in them really easily. So hands-down, for me, the Martellus map of 1491. If you have a minute, check out the link I provided to an article talking about the significance of this map. Pretty cool stuff.

What guides/books/websites would you reccomend where I can learn about the basics of image processing? I am about to take a course on image processing and eager to get started!

Excellent! I recommend you check out the software ENVI if you can, as it is an environment where you can learn about a lot of different image processing routines.

In terms of books... I'd check out Gonzalez and Woods book, Digital Image Processing. Any edition will do. I see their books everywhere in my building at school.

I do a lot of image processing in Python, so if you're new to programming, I recommend CodeAcademy.com to learn the basics of programming, and then I'd check out any documentation for image manipulation in python using scipy or spectral libraries!

Is it possible to check work that didn't use this technology to see if we've missed anything? I realize that certain pieces are almost untouchable but I think it's amazing knowing that we could be sitting on new information and never know it.

Yes it is entirely possible, and highly recommended that we do so soon! The longer we wait, the more time that aging and fading has to destroy the evidence!

There is a huge call to museums and universities to get their important artifacts imaged using multispectral/hyperspectral techniques!

Some pieces are much better candidates to put the time and resources into imaging them, but I know that if we had all the time and money, my team would image every document in the world.

if you could inspect any document that exists in the world today what would it be?

and a second question

if you could inspect a document that no longer is know to exists, or can't be proved to have existed but is rumored to have, what would it be?

Fun question! Okay, well I don't know about specific documents, but I'm an aspiring treasure hunter, and I'd absolutely love to image old treasure maps! That would be SO COOL. Very National Treasure-like.

I think the Lost Library of Alexandria exists, and I hope we are able to uncover some text that proves it's existence, or best-case scenario, where it is! You never know!

I work in these materials daily (Dead Sea Scrolls, Codex Ephraemi Syri Rescriptus, etc.). I presumed St. Catherines had been thoroughly raked through by now. Is there anything of historical religious significance (say before 4th century) that you expect will soon see the light of day?

Yes, we have been planning more imaging this summer at St. Catherines. There are very old copies of the Bible (presumably), and other materials that may contain undertext of a completely different nature.

If you set the documents on fire, will they burn?

Does Terry Tate know when you don't recycle? Answer here

First off, thanks for doing this AMA! In terms of your hours and free time, what is a general work day for you?

Of course! I'm so flattered that I'm getting so much attention! This kind of thing has never happened to me, not even in my dreams.

Well during the academic year, I work mainly on weekends. This summer, however, I work full-time on processing data.

My typical work day starts with checking my email, looking for requests from my scholar colleagues for processing specific images that have grabbed their attention.

I have a long long list of documents to process, and so I take the scholar's requests as priority, slowly checking things off the list.

I usually spend around four hours on one image, as that's about the time it takes for me to finish all of my processing routines in my arsenal. Then, I take the best results and create a psuedocolor rendering of them and send them off to the scholars for interpretation. Many times they are able to read entire words that they could not see or read before!

In terms of free time, there's honestly so much work to be done that there is never really any free time. However, while the computer is chugging through the processing, I have time to look into new statistical processing methods, and try them out on samples to see if they work or not! All in the effort to improve the results!

I have plans to go abroad to Germany this summer to image documents from the bombing in Dresden, so that will be about a week or so.

Hi there, fellow RIT student here.

My uncle has a journal from a Civil War soldier that he rescued in the 1960s from a refuse pile (a small local museum that was clearing out stuff they didn't find important) that he wishes to preserve. While I recommended turning it in to a museum or other people who know what they're doing, he's adamant on holding onto it (he's afraid of the decendents of the soldier swooping in at the last moment and claiming it as theirs).

What's something I could tell him to do to preserve it? At lease until the point he passes it onto his daughter (a curator of old documents). It's still readable, if that tells you anything.

I am not too knowledgeable on this matter, but I do know this: Keep it in a dust/dirt/water free container out of the light. Light is a big player in fading the text.

If you're a fellow RIT student, you might know about the Carey Collection at the Wallace Library. They would be EXCELLENT people to go talk to about just this. Please, please talk to them.

This may not be in your alley per se, but have you heard any professional scuttlebutt on the progress of the digital unwrapping and reading of the Herculaneum Papyri?

Hmm no I haven't heard of that specific document before I think. However, I'm sure there's something in my lab about it. My advisor Dr. Easton has his hands in everything going on in the document imaging world.

The wiki article looks like it's a 12 band (7 vis, 1 UV, 4 IR) and you did raking light in a visible band (blue) and an IR band (910nm) and it hints at some other methods like XRF being used.

Three questions:

• Was it just standard raking light or did you use anything like Reflectance Transform Imaging for surface normal mapping?

• Were any preliminary tests done with cameras with deeper IR penetration (like an InGaAs sensor that can record in the ballpark of 1500-2000nm) and if so were they just not showing any useful information/separation?

• Of the various methods and channels uses, was anything most striking visually to you?

Answer 1: That's a good question, I can immediately tell that you know some things. Raking light has been predominantly used on the documents that I've been working on. I can't say for certain about other methods.

Answer 2: Yes, I think that given the delicate nature of the documents and the fact that we probably only have one chance to image the documents, we check the documents for various characteristics that may tell us which type of imaging techniques could be the most beneficial. In some cases, we determine that multispectral is the way to go, and sometimes, infrared may be the focus. It all depends on the document!

Answer 3: Fluorescent ultraviolet has by far, the largest impact of any I've ever encountered. Sometimes text under this illumination stands out so much and the contrast is so amazing that no further processing needs to be done. It's incredible.

thoughts on the, mes aynak excavation situation in afghanistan?

I don't know enough about the situation to contribute anything of substance.

Links to any papers that explain the results you've obtained?

Any data you've worked with that we can play with?

My first co-authorship paper will be finished and hopefully presented at the IEEE conference in Rome this year, so I don't have a paper explaining my personal results. But please check out Roger Easton's website which I have linked in the original post. He has plenty of stuff to look at.

I can't give out any of my data right now, because I don't want to somehow get into any trouble. But! I encourage you to Google for RIT Archimedes data or RIT Martellus data or anything of the like, because I know there is some posted online that you can download yourself! Because if you find and download it yourself, then that's A-okay!

Have you found Ben Franklin's magical spectacles yet?

You can find them at walmart!

The team in which you work with - have you lot ever encountered a document which unveiled information which broke new grounds and changed the perception of what we know of the history of that period? If so, what was it and how did you (and the team) feel?

While I've been a part of the team, no, nothing ground-shattering.

However, in the recent past, the whole foundation for this type of research was, in all seriousness, accidentally stumbled upon. The main goal I believe was simply to enhance the text that we could already see a little, but they ended up finding a palimpsest, so an entirely new layer of text under the existing text.

I know the efforts at the St. Catherines Monastery have been quite fruitful as well. There's been talk about possibly discovering Shakespeare's 13th signature or more Archimedes works, it's all so amazing!

What are some texts or papers you would recommend as "required reading" for multispectral imaging? I'm hoping to begin an engineering project at work that will involve multispectral imaging of tissue for medical purposes.

Well for starters, the best book for any kind of spectral imaging work is Schott's book, Remote Sensing: An Imaging Chain Approach. Because honestly, we are always doing remote sensing, but on a smaller scale.

For a multispectral medical imaging focused book, check out Dr. M. Ali Roula's book. I know I've seen it around before, and it might hit the nail on the head for you.

Also find this book: Introduction to Medical Imaging by Nadine Barrie Smith. My classmates used this book for a medical imaging physics class and said it was amazing.

Do you think we'll ever get consumer/commodity hyperspectral imagers? Something akin to the FLIR One? Are there any hacks that allow cheap hyperspectral imagery?

What spectral ranges are useful? Is polarization also a useful signal at all?

Also curious about polarization detection. It is a relatively simple technique which has seen many applications in biophysical fields and can easily be combined with hyperspectral imaging.

Yes! Polarization is an incredibly useful method to isolate the important signal. While I'm not aware of the measures we take to polarize our light for document imaging, as an Imaging Science student, we study polarization a lot, and there is some incredible research into polarization being done by a few graduate students I know!

Yes! I think that is very possible! In the near future too! This technology is relatively new, but it's advancing so fast, so I foresee this technology being rapidly available!

Spectral imagery is achieved by simply collecting photons of a small bandgap of wavelengths with a sensitive detector. So, if you had a light source that emitted at all in a given wavelength, you could place a wavelength-specific filter over your detector and, if the exposure is right, you have yourself a spectral imager. Multi and hyperspectral are terms used to describe the spectral resolution of your system. I don't foresee hyperspectral technology being readily available just yet, but definitely multispectral. (multispectral: ~tens of bands --- hyperspectral: ~hundreds of bands)

Holy shit. we went to preschool-high school together. Hows it been man?

That's cool! haha Life's been good, I've been busy since high school!

why can't you disclose 99.9% of your work? I mean if there is an old document that is 100% unreadable, and now its readable but not disclosed. Is it like a service where people pay for you to reveal what they own and can't read, then they can do whatever with it?

I answered this in an above comment, but in short, we are privately funded, and it's up to the museum curators or universities what happens with the processed data. Typically, though, the museums will offer the processed data on their site for scholars and anyone who wants to study them.

I can't disclose anything, but after I hand off the data to the scholars, there's most definitely a good chance it will be available to the public soon after.

What Multispectral camera do you use?

MegaVision EV I believe. MegaVision

Is there a way to tell if document is "recycled" or not?

If the document shows signs of undertext when illuminated by infrared, ultraviolet fluorescent light, then the document may have been recycled and is a good candidate for multispectral imaging.

You mentioned that your colleagues have worked on the Archimedes Palimpsest. I saw a TIL that mentioned a monk writing over some of Archimedes' work that COULD have been the base of calculus waaaaay before Newton. Do you know if there is any truth to this? If so, would you be able to recover the lost text despite a monk writing prayers over it?

Yes, I posted on that article yesterday and was asked to do this AMA because of it.

There has been some text recovered from the Palimpsest, and while I don't know what it means at all, it's making the scholars excited to study. It could mean he discovered calculus, or it could be a bunch of bonk. We don't know yet.

We are able to see some undertext, despite the presence of the text from the monk being much more prominent.

We are still working on processing the Archimedes data more.

What is the most interesting, or oldest, and esoteric/occult thing you have recovered?

I haven't found anything quite so excitingly weird, but I really like finding text in places where it is doubtful that I find any. On the Martellus map, I find text in new places all the time, which is really exciting to me and the scholars I work with!

I have always been fascinated by the Voynich manuscript. Have you ever examined it? Do you have any ideas about its author(s) and purpose?

I am not familiar with that particular document, but when I'm all done with this AMA, I'm going to look into all these interesting documents that people are telling me about!

How would a school or researcher go about getting your team to preserve some documents?

They should contact Dr. Roger Easton at [email protected]

Another good resource is R.I.T's Cary Collection They could offer insight in the best way to preserve documents, and they would easily be able to contact our team for imaging.

What data analysis algorithms do you use? Is principal components analysis useful for your work? What is your preferred method of data analysis? I studied spectroscopy at U of R. PM me if you want to chat about multivariate statistical analysis of spectroscopic data sets. Best of luck with your research!

Principal component analysis is an incredibly useful routine. The produced bands are incredible, and sometimes the erased text is vividly enhanced this way.

I also perform ICA and MNF rotations, as well as various image filtering schemes and spectral math.

Hello Mr. Sacca, what was the most mysterious document you have found/recovered?

I have not found any documents myself. I just process data. However, the Archimedes Palimpsest seems to hold the most mystery. We are very anxious and curious about the text that has been lost.

I am a researcher of early modern books, and I'm currently part of a research group working on a project to digitise marginalia. I frequently come across books that have been subject to some sketchy attempts at 'conservation' and 'cleaning' which have really done a number on the handwritten ink and chalk. These are almost always a result of the varying values we place on these books - 400 year old marginal annotations are valuable now, but once radically decreased the value of the book, hence the attempts to remove them.

Do you work on things like this, where you're 'undoing' the work of early conservation, and if so, how do you do it?

I mentioned earlier that there have been attempts to conserve documents through imaging since imaging was invented. However, the methods that these earlier groups used were ineffective and risky. The solution our team provides is most often, very effective, and there is almost no risk.

That being said, it all comes down to the museum curators decision to allow us to image the document or not. We try our best to preserve the information while being as non-invasive as possible.

Are there any documents that you would really like to get your hands on? Additionally, have you applied your techniques to other materials that aren't just documents, such as art mediums to see if there's any hidden layers?

Yes, there are often good candidates for multispectral imaging in art. There are many works which have been known to contain hidden information within them. We've also done and further plan to do imaging of globes, which are made of various materials, sometimes even metal.

Do you take requests? I'm really keen on reading the memoirs of Lucius Cornelius Sulla, they've been lost for centuries but I'm holding out hope that a copy turns up at some point! Do you know anything about the work that's being done on the scrolls that have been discovered at Herculaneum?

I would not be the person to take requests. I'm more of the data processor/analyst guy. But I would recommend contacting the owners of pieces you think would be good candidates for imaging techniques and have them contact my team or another group who does the same sort of thing!

I do not know much about the scrolls discovered at the Herculaneum, but I'm hearing a lot about them, so I'm going to look into them when this AMA is over!

Do you do pattern recognition on the paper itself to date it? That was my grad project on Etchings from Rembrandt.

Personally, no, I do not. But, the scholars on my team may have dated the documents like that.

If someone has some old photos and they are trying to recover just barely readable text from the foreground, what can they do?

Well this is curious. Are these photos digital or are they printed?

If they are digital, then their spectral information is limited to RGB. If they are printed, then their spectral information is limited to whatever the printer capabilities are. If it's on film there may be something you can do, but I'm not really sure what the steps would be.

The way my processing works is it takes advantage of having many spectral samples of the target, each with their own piece of unique information. Then I perform something called a principal component analysis, which takes the parts that are similar and groups them together, which usually, (and this is the goal) reconstructs the text that is lost.

What's an example of a statistical image processing routine that you use?

Principal Component Analysis, Independent Component Analysis, and the list goes on.

What DPI do you scan documents in, or do you photograph them?

Do you ever wonder once recovering an old document that you might have missed something?

We photograph them, and we use a 50 megapixel sensor. A pencil stroke width in our images has a width of around 10-15 pixels usually. So these images are massive.

Yes, sometimes I think that the target should have been exposed longer, but there is a tradeoff with exposure time and resolution. Other than that, we do a pretty solid job covering all bases and recording each step.

Have you ever used computer vision techniques to try and extract otherwise illegible text or drawings? Do others in your field do this? I use CV techniques to extract meaningful data from images that might otherwise be considered "too noisy" or lacking spectral characteristics required for feature identification. If this kind of thing is interesting to you I'd be happy to discuss further - I really enjoy that feeling of taking a muddy image and making it clear again.

Yes! That is the main goal of my job! We do a lot of noise reduction techniques and spatial frequency filtering in the attempts to extract illegible text!

What kind of light do you use, which wavelengths?

We sample at wavelengths ~350 - ~950nm and then image using fluorescent ultraviolet

Why can't you disclose 99.9% of your work?

The documents are privately owned by museums, galleries, and universities, so it's up to them what to do with the physical document as well as the processed images.

What is the (general) nature of the 99.9% of your work that is undisclosable?

It's all just privately owned documents and materials. The reason why I can't give anything out is because it's really not my property to do so. It's up to the owner.

why cant you disclose your work ? its not like you are working on how to reveal underground bunkers, you are working on old documents :/

The documents are privately owned by museums, galleries, and universities, so it's up to them what to do with the physical document as well as the processed images.

multispectral imaging - is it capturing images with not just RGB filters but with other frequencies as well? or is there something more than that?

We capture 22 bands of images with wavelengths ranging from ~350 to ~950 nanometers, as well as some fluorescent ultraviolet bands. We use a precision tunable LED light source which allows us to select the illumination conditions, and then we place a specific filter over our detector to capture only specific-energy photons.

What is the weirdest document you have worked on? Like for example a random piece of paper that turned out to be a shopping list or something equally mundane, or perhaps a funny doodle or cartoon discovered on some official paperwork?

I haven't really worked on anything where the document turned out to be something mundane like that. Documents I work on have been kept in museums or universities private collections.

Can you do anything about reading the erased text in the Archimedes Palimpsest?

That is my main job. My job is help reveal the hidden text, and visually enhance the text and diagrams for scholars to read and translate. It's one of the most important documents I have to work on.

Which tools (in ENVI) do you use most frequently to process your images? Do you need to use other programs to complete the processing? You mentioned python, do you need to write your own algorithms or band math equations for best results? Tools you wish were present? (disclosure: I work for Exelis VIS and I am curious how you are performing this work since it is an atypical application for the software:)

I use PCA and ICA a lot, as well as MNF and strange combinations of bands for spectral math. We do a lot of filtering too, edge detection, low pass, high pass, and median filters can all be really helpful!

In Python, I can write pretty much the same processes that are available in ENVI, but Python appeals to me because it is open source and I could distribute the source code for free if I finish it. I use ENVI mainly now because my Python code is incomplete and ENVI is much, much faster than my Python algorithms.

Were some scientific discoveries in those documents, of which we didn't thought people had it back then?

Or were there even discoveries we didn't make, but learned about trough the documents?

Well I know as a kid we were taught that people in the 14th and 15th century thought the world was flat, and that Columbus was going to sail off the edge of the Earth.

This is a myth, and proven over and over again. Educated people back then knew the Earth was round, and evidence from the Martellus backs it up.

I'm a big fan of old documents myself. Whats the best way for someone to get into this field of research?

This research was what made me change my major into Imaging Science. After I switched, I bugged my advisor for over two years before he hired me and I got to start working on this stuff.

The best thing to do is actively contact people in the field. Let them know you are interested, and study up on the subject so if an opportunity presents itself, you can demonstrate that you are a useful person to have helping!