Photogrammetry on sunken ships

[USS ALASKA]

http://www.bbc.com/news/uk-scotland-highlands-islands-36357542

Hopefully coming to a Civil War wreck near you...

Cheers,
USS ALASKA

 

[JohnDLittlefield]

The questions that no one seems to be asking are:
What is the utility of such technology?
Is the added expense and time involved to convert 2-D images to a 3-D map to a 3-D print out worth the effort?
Does the effort yield any more information?

As an archaeologist, I worked with a 3-D tech team a couple years ago and was asked to evaluate a couple of ancient wreck sites (3rd c. CE) based on images that were converted to 3-D mapping images. I could offer no more info based on the 3-D map than from the 2-D images, which was very limited: simply a relative date for the wrecks based on styles of surface artifacts.
So, as interesting as the tech is, the utility of the application to wreck sites appears to me to be extremely limited.

 

[georgew]

The questions that no one seems to be asking are:
What is the utility of such technology?
Is the added expense and time involved to convert 2-D images to a 3-D map to a 3-D print out worth the effort?
Does the effort yield any more information?

As an archaeologist, I worked with a 3-D tech team a couple years ago and was asked to evaluate a couple of ancient wreck sites (3rd c. CE) based on images that were converted to 3-D mapping images. I could offer no more info based on the 3-D map than from the 2-D images, which was very limited: simply a relative date for the wrecks based on styles of surface artifacts.
So, as interesting as the tech is, the utility of the application to wreck sites appears to me to be extremely limited.

Would this also apply to the two American schooners from the Revolution on the bottom of the Great Lakes? At least one is still upright with the masts in place.

 

[JohnDLittlefield]

I assume you are referring to Hamilton and Scourge (War of 1812 merchantmen ships), both of which have been subjected to remote archaeological survey and photography via ROVs (remotely operated vehicles- robots), I believe. In these cases, the water is usually very murky and may not allow for photographs to be taken at a great enough distance to be applicable to 3-D imagery (with high-res cameras, the closer the image, the larger the file and with the visibility of those sites, I presume the completed file size would be tremendous), but someone with more expertise than I would need to address this aspect; my experience has been in the Mediterranean with crystal clear water.

Regardless, the question remains, assuming enough good photos could be gathered to produce a 3-D plan, what is the utility? What knowledge can be gained?What are the benefits, other than having a (rather beautiful) visual keepsake?
Perhaps I am too limited in my vision of and experience with the technology, so thoughts are more than welcome.

 

[USS ALASKA]

For the great unwashed like myself, the benefit would be to better visualize the wreck. The underwater collages are cool for what they are but those 3D renderings really bring to life the state of the remains. So maybe just getting people, who would not normally think much of it, interested is the only service this might provide. Greater numbers, greater interest, maybe greater funding? Or am I reaching here? But as you stated, this might not have much greater application to the professional than the already available depictions.

Cheers,
USS ALASKA

 

[JohnDLittlefield]

Public outreach potential is a very valid point and in my opinion, would likely be worth the effort if you are trying to gain funding, particularly from lay-person foundations and government entities.

 

[USS ALASKA]

Then the last thing left to do is the cost / benefit analysis. Does any potential 'higher visibility' outweigh the time / money / effort needed to produce these items?

Cheers,
USS ALASKA

 

[OwenRichards]

There are several plus points.

1. Several of these wrecks are in busy shipping lanes. Many of them have already been damaged by dredging operations. Making a permanent record now may be the only thing that exists of these ships in times to come.

2. Little is known of many of the vessels. As an example, with the Manassas, one of the first ironclads to see action in the Civil War, nobody can even decide how many smokestacks she had. A careful examination of the wreck-site (possibly using radar and/or sonar to get more details and get around the silty water) would be a great way to be able to study what was left of the ship and try and work out how it was originally put together.

Another point is that this approach would allow more people to take part in trying to find out how the ship was constructed. Apart from the experiences of Mr. Ballard and Mr. Cameron, it is often impractical to send archaeologists, engineers and computer artists down to the bottom of busy waterways to examine a wreck for themselves. Being able to see the whole wreck from different angles in the comfort of your office can often reveal insights that you would not receive by examining it on the riverbed.

 

[USS Cumberland]

They need to perform 'photogrammetry' on the CSS Manassas and count the number of smoke stacks.

 

[JohnDLittlefield]

They need to perform 'photogrammetry' on the CSS Manassas and count the number of smoke stacks.

That could possibly be done with much less expense and effort using a simple (3-D) fish finder or magnetometer

 

[JohnDLittlefield]

There are several plus points.

1. Several of these wrecks are in busy shipping lanes. Many of them have already been damaged by dredging operations. Making a permanent record now may be the only thing that exists of these ships in times to come.

2. Little is known of many of the vessels. As an example, with the Manassas, one of the first ironclads to see action in the Civil War, nobody can even decide how many smokestacks she had. A careful examination of the wreck-site (possibly using radar and/or sonar to get more details and get around the silty water) would be a great way to be able to study what was left of the ship and try and work out how it was originally put together.

Another point is that this approach would allow more people to take part in trying to find out how the ship was constructed. Apart from the experiences of Mr. Ballard and Mr. Cameron, it is often impractical to send archaeologists, engineers and computer artists down to the bottom of busy waterways to examine a wreck for themselves. Being able to see the whole wreck from different angles in the comfort of your office can often reveal insights that you would not receive by examining it on the riverbed.

1. if wrecks are in busy shipping lanes, it's very likely that no one can approach them without very special permissions due to the safety factor, so photogrammetry may not be feasible anyway, thus no 3-d model

2. you are correct... photogrammetry and a 3-D model of Manassas would be nice, but as you mention, a fish fisher or magnetometer could very likely answer the simple question of the number of stacks

3. If archaeologists, engineers, etc. can't get to the sites, then it's unlikely anyone else can get to them as well, so I am not sure what you're saying here, but my original point was that 3-D printing may not offer any real benefit as far as interpretation of understanding of a site is concerned. To me, the 3-D technology seems just a novelty for the most part.

As far as dissemination goes, there are actually much better ways to share site and artifact data publicly, if that is the goal. For example, once the process of photogrammetry or scanning is completed, a manipulable PDF can be shared via email or flash drive that allows the user, using only a PDF reader to see the site in its 3-D entirety- the expense of this is very little and can serve the role of public dissemination much more efficiently. Since a 3-D print is a tangible physical object that can only be possessed by a limited number of people, a sharable PDF seems to me to make much more sense for dissemination. I would be happy to send anyone a sample PDF, but the file is too large to include here- email me at [email protected] if you would like to see it.