Light, Cameras, Action!

Light, Cameras, Action!

One light, eight cameras, and a whole lot of action! After two straight days of transiting (the world doesn’t need another photo of my messy counter here on the ship; hence no blog posts these past two days…), we were anxious to get back in the water. I was particularly excited because we are at my favorite location in the Northwestern Hawaiian Islands (Pearl and Hermes Atoll), and the morning dive team (myself included) headed to my favorite dive site here… a site we call “Prognathodes Point”. We first found this site by pure luck back in 2009. We had picked some random spot with a depth range of around 200 feet (60 m), and were stunned by the dramatic ledge geomorphology and incredible diversity and abundance of marine life that we found. Among other things, we collected three specimens of an undescribed species of butterflyfish in the genus Prognathodes, from which the dive site derives its name.

Rebreathers and other dive equipment are staged on the ship in preparation for loading on the dive boat.

This year, I had a very specific mission for my dive to Prognathodes Point. One of the other researchers on this cruise is Dr. John Burns, who is integrating photogrammetry with geospatial software to generate 3-dimensional renderings of coral reefs, to monitor ecological characteristics and coral health. Brian Greene and I have been TOTALLY geeking out talking to John about how to create these underwater 3D photo models by taking hundreds of overlapping pictures of the area to be modelled, and then processing them using Agisoft Photoscan Pro software. My mission on this dive was to swim all over the dive site and take as many pictures as I could of the whole area, while Brian collected fishes and John Hansen and Brian Hauk conducted surveys. During our 25-minute bottom time, I managed to take 466 images of the site. I was incredibly skeptical that these haphazardly captured images would somehow magically transform into a 3D model of the reef, but I was stunned and amazed at the AWESOME results John was able to get using PhotoScan Pro!

A 3-dimensional reconstruction of “Prognathodes Point”, created from 466 image files stitched together. Divers were added via PhotoShop to show scale, but are positioned where the diver images were actually taken.

The image you see above is a screen-grab of the 3D model. The black regions are areas where I missed getting sufficient images, but given that it was my first attempt to do this sort of thing, I am simply amazed at how good the results were. I added two images of divers to show the scale. Although the diver images were added by Photoshop, the two original diver photos were taken at exactly the same spots where they are depicted in the composite image above. But the image above is just the tip of the iceberg. What John Burns actually created is a full 3D model that can be manipulated and analyzed in a computer. Brian Greene took the model and used some computer wizardry to convert it into both a dynamic, interactive PDF file (If you download it, you can spin the model around with a mouse), and as two different video tours, a short version and a long version. What I find most astonishing about this experience is that in one 25-minute dive, using a normal underwater camera and a single light, I managed to capture enough information that a complete 3D rendering of the entire reef could be easily created and shared online! The research potential for this sort of capability is staggering!

Brian Greene mounts a GoPro camera on his rebreather, allowing him to capture on video what he captures with nets.

While I was swimming around in circles photographing the reef, Brian was collecting incredibly cool fishes, and also doing some innovative imaging of his own. Brian has been perfecting what we are calling the “Greene Cam” (the natural progression of the “Greene Light” — a light we mount over our shoulders for deep diving). The Greene Cam is basically a GoPro camera in an underwater housing that looks out over the top of Brian’s head as he conducts his dive. The videos he captures are incredibly entertaining to watch (especially when you listen to Brian’s helium-voice commentary on the dive), but also scientifically valuable. In the frame above, you see Brian collecting a specimen of the species for which Prognathodes Point is names. He also collected a juvenile Elegant Anthias (Caprodon unicolor) — which as far as we know is the first one ever captured alive. Among his many other important specimens were three juvenile Struhsaker’s Damselfish (Chromis strusakeri) — a species we encountered for the first time two years ago here at Pearl and Hermes Atoll — which also represent the shallowest record ever for this species (220 feet / 66m).

Dozens of Galapagos Sharks (Carcharhinus galapagensis) hang around while the deep divers decompress at Maro Reef.

I mentioned at the start of this post that our activities today included eight cameras, but so far I’ve only mentioned two. The other six cameras are part of a GoPro 360-degree (omnidirectional) video system that I have been playing with on this trip. I had a spectacular dive with this system at Maro Reef earlier this trip, and today while the second deep dive team was completing their decompression, I deployed it again. I’m still learning how to make the cameras record properly, and I am a true novice at using the software to stitch the videos together into a full, immersive 3D experience. John Burns is also an expert in this imaging system as well, and has been an enormous help getting me started. I’m getting more and more footage with this system almost every day, and I’m excited about how it will all look once I stitch it all together. I’ve had some great encounters between the camera and marine life, and I’m sure more are forthcoming on future dives. The image below is just a teaser of how up-close and personal some of these encounters have been!

A large Ulua (Giant Trevally; Caranx ignobilis) comes in for a close inspection of one of six GoPro cameras filming 360-degree video during decompression.

All in all, it was a fun and exciting day, both in terms of diving, and for creating incredible 3D photo models and video experiences!