Friday, October 7, 2016

Using Structure-from-Motion (SfM) for Rock Art

One of the coolest presentations from last week's URARA symposium in Delta was the one by Robert Mark and Evelyn Billo on using photographs to generate 3D models of rock art sites.  The technology is closely related to that used with Microsoft's Photosynth program which I wrote about in my blog a few years ago.  However, while Photosynth allows you to zoom around and view a site from the point of view of each camera shot, the tools that Mark and Billo were talking about allow you to actually reconstruct the site as a 3D mesh and overlay the information from the photos as a texture using the same technology.  This is really cool.

Pictograph Panel on Black Rock Mesa
To test this out, I took a series of photos of the boulder above which we visited on the Monday URARA field trip.  I got it from three or four different angles and shot it in close up sections.  I then input these images into two programs.  1) Agisoft Photoscan, which is the program that Mark and Billo talked about at the symposium, and 2) Autodesk ReMake, which I found online.  Photoscan has a free 30-day trial and seems to generate better results, but it costs $179 for the basic version.   ReMake runs the analysis on the cloud and can be much faster, but costs $30 per month once the trial version expires.

Below is a clip of the model that ReMake generated in the form of a quick movie.

The Photoscan-generated model can be viewed at this link.

Here are the same photos at Photosynth.

Monday, October 3, 2016

URARA 2016 Symposium

I just go back from my first attendance at the Utah Rock Art Research Association (URARA) annual symposium.  This year it was held in Delta, Utah.  It was one of the funnest experiences I've had in a long time.

Sheep from Miller Canyon

Sunday, September 18, 2016

Nine Mile Canyon

The Pregnant Buffalo
This past weekend I took my first field trip with the Utah Rock Art Research Association (URARA) and got to see some of the rock art at Nine Mile Canyon.  The trip was every bit as spectacular as I had been lead to believe it would be.  The rock art is so extensive there it would take years to see it all, but I did get a good sampling of many of the well-known sites and quite a few of the lesser-known ones as well.

Monday, September 12, 2016

Parowan Gap

"The Zipper" at Parowan Gap
This past Saturday, my wife and I were in Cedar City to see a couple of plays at the Shakespeare Festival.  With some free time in the morning, we opted for a trip out to Parowan Gap to see the petroglyphs there.  It was worth the trip, though I wish I had brought a real camera.  Instead I had to rely on the iPhone for the photos here.

Dinosaur National Mounument Rock Art

Figure from the panel at Cub Creek in Dinosaur National Monument
In mid-August, I took a trip to Dinosaur National Monument with my two youngest children.  We visited three of the 5 well-known rock art sites in the park: Swelter Shelter, Cub Creek and Pool Creek.

Fremont Indian State Park

Sheep Petroglyphs at Fremont Indian State Park in Utah
Fremont Indian State Park is located alongside I-70 in Sevier County, Utah.  The site was discovered in the 1980's when the interstate was constructed in Clear Creek Canyon.  This site was the largest collection of Fremont houses at a single site ever discovered in the state of Utah.  Sadly, most of these were destroyed in the construction.  However there was a great deal of archeological work done and Fremont Indian State Park was created in 1987 to preserve what was left.

Monday, August 24, 2015

'Winged Monster' Rock Art Finally Deciphered

I woke up to this news at Real Clear Science today. This is pretty cool.

'Winged Monster' Rock Art Finally Deciphered

Black Dragon Canyon is one of my favorite rock art sites. It's named after a winged figure that early rock art aficionados thought they saw and then outlined with chalk.

"I myself visited the site in person a few years ago," said Phil Senter, an associate professor of biology at Fayetteville State University in North Carolina, who was not associated with the study. "There's no pterodactyl there at all. It's a collection of other images."

This has been known for quite a while, but the images they were able to tease out of DStretch (see earlier post here) are stunning.

from the article