International NAS member Dirk Berg is from Germany, but lives in Kosovo and regularly pops over the border for a bit of diving in Greece. He came to the UK for first time to dive on the underwater photogrammetry course, and loved the challenge ... 

 

Arriving early Monday morning in July on site at Stoney Cove, I queued with many other scuba divers and swimmers – these were the days with record breaking high temperatures!

Our host Jezz Davies and our tutor Martin Davies welcomed our small group of four students and then introduced us to photography and photogrammetry in general and to the challenges of taking pictures under water. Soon we were already doing the first dry practical which involved the familiarisation with and preparation of the different cameras, selecting the correct settings, how to operate the camera and – last but not least - to make sure that we had enough battery and memory available during the dive!

After a short lunch break, we went into the “hot” water practice. Thanks to Education Manager Peta Knott’s email alerts “it’s going to be hot!” I had brought my wet-suit. For the first time I didn’t admire my buddies in their dry-suits - in our working depth of only 7 meters, Stoney Cove water was 19° C!

The visibility around our chosen object was blurry, the cockpit covered with green slime. My buddy Jacqui and me, decided to take pictures anyway, starting on different ends of our object, then slowly moving around clockwise, to avoid disturbing each other’s view. For good results, every picture taken has to overlap with the previous one, therefore we collected some 200 – 400 pictures during the dive – each!

Image: Underwater photo at Stoney Cove

In the next hours, Martin walked us through the free trial version of the Agisoft Metashape Software. Due to the number and quality of your pictures and the specs of the laptops, data processing took some time, my laptop calculated more than 6 hours to complete this work. But Martin was prepared for such cases, and on his high-powered PC, the same process took only several minutes until displaying some surprising results.

 

Image: photos being processed

One of the features of the Agisoft program is indicating where spots were missed out (usually the underside of the objects) or where more information was needed. So, on Tuesday morning, we fixed these patches in a second dive. The warm water and the extended dive time in the shallows allowed me to capture more pictures of other objects for practicing my new photogrammetry skills.
More data processing sessions in the afternoon hours were rewarded with stunning, amazing results, which we shared, just in time before the course ended.

Image: final processed model that the author was very happy with.

This course is fun to attend, and I recommended others to take it. And of course, the skills and the application of the program can also be used on dry land :) 

There are still places available on the dry one-day Photogrammetry of Archaeological Artefacts course on Saturday 3rd December at Fort Cumberland, Portsmouth.