This week we are rolling out CHI’s new free forums for the community of people who are developing and adopting Reflectance Transformation Imaging (RTI) and related computational photography. We have had the idea to do this for some time, and after trying a couple of different forum software packages, getting input from friends, and tinkering with some of the forums setup, we are now ready to invite the larger community. Join us! Sign up for a forums account now: go to http://forums.culturalheritageimaging.org and click the link “Sign In” in the upper right of the window to begin setting up your new account. You can look at content in the forums without an account, but a free account is required to post there (this is to keep the spammers at bay).
As our RTI training has expanded, and more people are adopting RTI, we are frequently asked how users can see what other people are doing with the technology, and whether CHI offers a place to find answers when difficulties arise. We know many people want to keep up with the latest news on software releases, equipment, and related topics. Our forums were created to answer these needs. We hope to see the RTI community help each other and share their experiences and insights.
I’d like to say thank-you to those who made this new forums service possible. First, thanks to the Institute of Museum and Library Services (IMLS) because we were able to use a little funding from our 21st Century Museum Professionals grant to get the forums going. This grant, which has enabled 10 4-day training sessions in RTI — we just finished the 9th one this month — has also helped us support updates to our software, user guides, and other materials associated with the adoption and use of RTI at museums and libraries. Sarah Ross did a fine job installing and setting up the forum software for us! The team at CHI has already added content to get the forum going and answered questions that have come in. We have had a great group of beta testers who tried this out, posted content, and gave us feedback.
We hope that you, members of our community, will engage in the forums, asking and answering questions to help each other. This is just the beginning; we plan to expand the forums to cover additional topics as the need arises. Please write to us and let us know what you want from the forums: what will make them the truly useful for you? Send your comments or questions in an email to: forums at culturalheritageimaging.org
On August 16, 2002 we founded Cultural Heritage Imaging as a nonprofit corporation in San Francisco. Wow, it seems like yesterday and it seems like a long time ago! Our digital camera at that time was 3 megapixels and it had a pretty slow auto focus. We had seen Tom Malzbender’s pioneering Polynomial Texture Mapping paper at SIGGRAPH in 2001, and we began working with him several weeks later. However, using the technique required working with command-line software and capturing images using either a lighting array (dome) or a very time consuming detailed template approach.
CHI’s manual RTI rig – 2004
We were shooting some 3D using structured light software from Eyetronics, and we had been on site with Professor Patrick Hunt of Stanford University at his archeological excavation at the Grand St. Bernard Pass in Switzerland as early as 2001.
Mark Mudge, Carla Schroer, and Marlin Lum on location at the Grand St. Bernard Pass in August 2004
We have come a long way since then, working with numerous museums, historic sites, archaeologists and historians, as well as computer science researchers. In 2006 we developed (with Tom Malzbender) the Highlight RTI technique, and we worked with the team at the University of Minho in Portugal to develop open source software to support that (RTIBuilder). With a grant from the Institute of Museum and Library Services beginning in 2006, we researched a multi-view approach to RTI and out of that collaboration with Professor James Davis et. al. of UC Santa Cruz and the Visual Computing Lab in Pisa came the open source Hemispherical Harmonics fitter (section 6 in the tutorial notes) and the RTIViewer.
Also in 2006 we were contacted by folks at the Worcester Art Museum Conservation Lab interested in using RTI for art conservation. After a small pilot project, we built a light array for them and trained them in the RTI technique. To this day we appreciate this group, their vision of how this technology could be used regularly in their field, and their willingness to go out on a limb to make to make it happen and share their work with others.
Worcester Art Museum Conservation Lab – May 2008
In 2008, as interest in RTI grew on the part of museums and historic sites, CHI made a great effort to develop training programs for RTI and other computational photography techniques. We have since trained over 200 people in our full 4 day RTI class, and we have introduced hundreds more to RTI through workshops and presentations at numerous conferences and lecture series.
Our current research work includes an NSF funded project with Professor Szymon Rusinkiewicz of Princeton University to further develop the technique of Algorithmic Rendering with RTI data sets and easy-to-use software that includes a way to keep track of the full process history in a digital lab notebook. We began working on the requirements and methodology for how to manage this process history for all of our imaging work and especially RTI back in 2002, and we shared it with the computer graphics community in 2004 on a SIGGRAPH panel called “Computer Graphics and Cultural Heritage: What are the Issues?” chaired by professor Holly Rushmeier. Our early work referred to this subject as “empirical provenance,” described in detail in this 2007 paper delivered at the CIPA conference.
So now, 11 cameras, many well-worn travel bags, and I can’t even count how many laptops later, we enter our second decade of collaboration with many wonderful people from all over the planet. We thank some of the folks who have helped us along the way on our acknowledgments web page but it isn’t and can’t possibly be a complete list. CHI was founded on the principles of collaboration and the democratization of technology, producing tools and methodology that enhance scientific reliability and long-term preservation.
We would like to say thank-you to everyone who has volunteered time, donated money or equipment, shared their work, asked us questions, answered our questions, written down how to do things, listened to us speak, formed project collaborations, or run across our path in some interesting way! We hope to meet you all again, and many others down the road.
Cheers!
Filed under: Commentary, Training, Uncategorized | Tags: ACR, batch, processing, zero, zero out
During the post processing phase, when you open your DNG files in Adobe Camera Raw (ACR), you have an opportunity to adjust your white balance and your exposure compensation. Prior to making these adjustments …
We recommend that you create a “Zeroed Out Settings” custom preset, and apply it to the entire image set. Consider making this your default preset for Adobe Camera Raw. To do this, set all of the settings to 0, then save as a named preset using the flyout menu for the Basic image adjustments panel. In particular, make sure all sharpening options are set to 0.
Make sure that your Zero Out Settings match the above screen shot (click image).
Check the settings in all of the tabs. The first three tabs (Basic, Tone Curve, and Detail) have default settings that are non-zero; the radius setting on the Detail tab cannot be less than 0.5. In other tabs, default settings are already zero. (as taken from page 5 in the RTI Highlight Processing Guide v1.4)
‘Zeroing Out’ data ensures that your data is not being processed, interpreted or stylized to fit consumer tastes.
Filed under: Commentary, On Location, Workshops | Tags: mark christal, NMAI, pano, rockart, scouting
Reconnaissance. Scouting. Preparation.
Marlin Lum here. Imaging Director at Cultural Heritage Imaging. This blog entry inspired by Mark Christal, strong man and multi-media super genius employed by the National Museum of the American Indian (NMAI) at the Mall in Washington DC. It’s part of his professional game to find out as much as possibly about a topic and then present it to the public via modern visual technology. Go to the National Museum of the American Indian and check out what they are putting out in the world, really good stuff.
panorama photograph: scouting for rock art in a river bed
Mark is a graduate of CHI’s 4-Day RTI Training and a NCPTT Workshop participant where he not only refined his skills in RTI capture but also learned about photogrammetry. Aside from being a respected technologist and dedicated vegan, he is also an enthusiast of ancient Rock Art. (no- not album covers). Native American rock art.
Taking his Panorama and RTI capture skills in the field, (meaning a 14 mile mountain bike route, hot weather, lots of photo gear on back), Mark and his crew (also (former) NMAI super genius Video Master, Kevin Cartwright) entered the wilderness on a reconnaissance mission. Mission: to locate a petroglyph, shoot a Pano and scout it for future RTI capture.
I also have to mention, as stated by Mark, ‘that the park ranger had never heard of this (culture) site’. Mark and Kevin only found it after actively looking/hunting, and having followed a good tip from a kayaker. According to Mark, ‘this might be the only known on-site rock art in Maryland’. Mark goes on to say that, “The only other site (Bald Friar) was dynamited in the 20’s because it was about to be flooded. Parts of that site are now spread across the state in a number of museums and culture centers”. Uhmm. Can you say, ‘sense of urgency’, get out there and document people!
A long time ago I used to work in Hollywood where I knew a location scout. It was his job to discover everything, everything about that location and bring that information back to the unit. His checklist asked questions like: Where is this on the map? What direction does it face? Where is the afternoon sun? Can I get a crew here? Do I need extension cords? Whats the scale of the artwork? What lens do I need? Is my tripod in dirt or water? Who’s land is this? What’s the deal with the roaming horned bull? (true story btw). And where is the crew bathroom?
You get my point. The more you know about your subject (and its owners {past and present}, the better). A thorough knowledge base about what exactly you intend to RTI is essential for creating a successful final product. It’s like anything else, knowing what equipment you’re gonna need (and what you don’t want to carry {or bike} for 14 miles) is gonna make or break it (your back that is).
Hollywood crews might research and setup a shot for months, only to have the actor whisper his lines in 40 seconds.
I will draw a conclusion to this blog and just point you to the large JPEG that Mark Christal email me from his Recon mission into the hot sun. (For those of you shooting in the comfort of a photo lab, you will have your chance.)
Mark’s Recon Pano gives us a glimpse into the beauty, the full shade during full sun, the water level during that time of year, the artwork and the scale (note calibration stick). And for those of you who are curious, yes, this location IS top secret, so, no use in hacking or looking. One last thought, shoot a capture when the water is running low.
Scout and be happy!
check out the flat pano image here on Flickr! Click on the Hi-Res image – can *you find the rock art? (look for the calibration stick)
Go directly to a large the jpeg: http://www.flickr.com/photos/markchristal/3938203809/sizes/o/in/photostream/
Filed under: Commentary, Guest Blogger, On Location | Tags: AIST, Archaeological Research, Archaeology, argon, Digital Preservation, guest blogger, Lake Jackson, Reflectance Transformation Imaging, RTI, virtual archaeology
This is a Guest Blog by Photographer Joseph Gamble.
As an affiliate with the University of South Florida’s Alliance for Integrated Spatial Technologies, I traveled with a team of archaeologists doing imaging research and 3D laser scanning of artifacts to Tallahassee last year to work in the Florida State Bureau of Archaeological Research (BAR) and experiment with RTI on a number of Native American artifacts from Lake Jackson, Florida. AIST Directors, Drs. Travis Doering and Lori Collins along with AIST archaeologist Dr. Jeff DuVernay, helped me to manage a challenging RTI of a Native American copper breastplate as well as other copper and metal objects from Lake Jackson and several other Florida sites.
Native American copper breastplate from Lake Jackson, Florida
The artifacts were from the ancient Lake Jackson settlement, a civic-ceremonial center of a Mississippian chiefdom that flourished across parts of northern Florida between c. 900-1500 A.D. The breastplate (23 X 54 cm) was cold-hammered from a sheet of native copper and contains extensive iconographic and symbolic that today are faint and difficult to discern. In the 1970s, the piece was encased in a clear Plexiglas, cube-like chamber that had been infused with argon gas as a conservation measure to halt corrosion of the artifact. The reflective polymer barrier that enclosed and protected breastplate seemed to pose an insurmountable obstacle for its accurate high resolution documentation. To stabilize the breastplate it had also been pressed into a plaster base to prevent further fragmentation and distortion leaving the piece with a cracked or crenelated surface texture. This condition was an additional for the documentation because of the shadowing that further limited the usability of the image set.
To acquire an inclusive data set that would contain sufficient usable images to build an RTI, we placed the case on black velvet, mounted the black balls and commenced to shoot. The total image count came to 156 raw files of which 57 were used to build the RTI file and, much to our delight, it worked well.
View the Final RTI File by clicking here (you tube video).
Joseph Gamble is a previous 4-Day RTI Training graduate. You can learn more about Joseph Gamble Photography at: http://www.jcgamble.com/
You can learn more about the Alliance For Integrated Spatial Technologies at: http://aist.usf.edu/
Filed under: Commentary, Equipment | Tags: breeze software, canon, capture software, focus, nikon, software, Technology
I was recently asked, ‘What DSLR camera is better for RTI data capture? ‘Canon or Nikon?’ The answer is like Godzilla Vs King Kong. Its gonna be a good fight.
The Short Answer is that either camera will work.
In the hands of a professional photographer, they are both very similar. The difference is the workflow – what you’re familiar with, what high quality lenses you own, and what equipment you’ve already got in your gear bag and studio ——— and what “Capture/acquisition Software” you decide to start a relationship with. (think Mind/Body – these two need to be pulling on the same oar)
Capture Software
Before you purchase a camera, you need to examine *how you’re going to interface with your DSLR when you’re shooting in *tethered* mode. Here’s the scenario, your stage is setup, your object is in place, you’re tethered to the camera via USB cable, and you launch your ‘capture software’ App. You need complete command of the basics : Composition, Exposure and Focus.
DSLR Remote Pro for Macs (Canon -> Mac)
http://www.breezesys.com/DSLRRemotePro4Mac/index.htm | http://www.breezesys.com/products.htm
The most stable Capture Software that we have used (bare in mind that we use Macs and Canons), is coded by a third party guy, Chris Breeze. He has taken the (Canon and Nikon) SDK and developed for a “combo” of Canon, Nikon – Mac, PC configurations. I’m not going to deep dive into the setups, but what I am going to state is that (at this moment in time), the Breeze software is stable, solid, is easy to use, and hardly *ever crashes. The user interface is Ok, a bit bare bones, but this tool gets the job done, and thats what we all want. Again, bare in mind that we use Macs and Canons (we have only used the Canon—Mac version). This software is installed on all our computers is our goto tool for image acquisition procedures.
The main user interface is a bit bare bones, but DSLR Remote Pro is solid and can handle minute focus adjustments needed for RTI production environments.
The last version of the Nikon Control Pro 2 software that I experienced worked really well, *except for the fact that it was difficult to check focus and scroll around bc that particular window has/had a restricted pixel size. It wasn’t as small as a thumbnail, but lets say that it did not take advantage of your screen size. All of the other functions were well behaved. Check it here: http://www.nikonusa.com/Nikon-Products/Product/Imaging-Software/25366/Camera-Control-Pro-2.html
The Canon Capture Utility (free with the purchase of a new camera) has a great interface, looks clean, works well, but it could be better, much better — it could be more stable. Sometimes it just flakes out and crashes. We used it for years with lots of happy moments, but towards the end we had a bitter break up. As RTI grew and we pushed the technology, we began to experience flaws. Specifically, with the ‘Live View Focus Controller functions’ (and its algorithms). Numerous frustrating crashes occurred when we asked it perform fine focusing adjustments in the ‘magnified mode’. This is pretty important considering that RTI *requires the subject to be in focus. Software crashes were even more problematic when we used a modified IR / UV camera — for some reason(s) that we can not explain, the software just didn’t adjust well to the different wavelengths of light under those conditions.
A few more comments:
If you use ‘good Glass’ (think prime lenses+superior optics) both the Canon and Nikon are going to get you professional results. We know many many Canon RTI shooters as well as a few Nikon shooters (and hasselblad-er(s). I think that the majority of users tend to be Canon. When we are asked to purchase equipment for client(s) we always steer them towards the Canon family.
With that said, I have seen professionals purchase a suite of Nikon gear and then *re-convert all the new gear and go to Canon. (and from ongoing conversations, they didn’t go back to nikon).
At CHI we’re Canon all the way.
Thanks for reading, Happy F-stop.
-marlin.
Filed under: Commentary
In the summer of 2012 I lost a dear friend of more than 20 years to lung cancer. Debbie’s and my friendship began in the workplace in the late 80′s, and blossomed into so much more. We hadn’t worked together in more than 20 years, and yet we stayed in close contact and got together for regular dinners every couple of months. Debbie was a remarkable person in many ways, but if you asked her what the most important thing she ever did was, she would say being a mom to Katie. After Debbie’s passing, I was touched when Katie told me she had selected Cultural Heritage Imaging as her mom’s favorite charity and one she would ask Debbie’s friends and colleagues to support in her honor. I was genuinely moved when her colleagues at PG&E and other friends raised more than $1500 in her honor. Wow!
Debbie was a long time supporter of CHI making an end of year donation every year in varying amounts depending on what she could afford. She was also someone who provided moral support, by gently encouraging me to keep going, even when the work and the fundraising felt overwhelming. She told me me how important she thought CHI’s mission was, and she especially liked that we were helping others create lasting records of cultural heritage materials that would be around for her daughter and someday maybe her as yet unborn grandkids. I miss her.
I want to say THANK YOU! to all who donated in Debbie’s honor. We promise to put the funds to good use in supporting our mission and programs, and in spreading our work around the world.