Where does your diving take you?

How should I frame this? Selecting better video frames for photogrammetry

Selecting better frames

Sometimes my spheres of interest overlap.

Meeting Matt Carter at OzTek a couple of years ago, and working with Pim Bongaerts on mesophotic.org introduced me to photogrammetry, and over the past few weeks I’ve been processing some models using 4K video.

Selecting useable still frames is tedious at best: manual selection is a non starter, and basic selection with ffmpeg often produces blurred frames.

I solved this with framer.sh, a script for selecting better frames.

Feel free to use and improve it. Pull requests accepted.

Gas Manager

I’ve finally released my new gas management program for iPhone & iPod touch. Gas Manager helps you choose and blend custom gas mixes for diving. It includes partial pressure blending (with fudge factors), top off and best mix, as well as MOD, END and EAD calculations.

Check it out!

The Thresher Shark Research & Conservation Project

In 2011 I’ll be returning to The Thresher Shark Research & Conservation Project for a six month stint as Science Officer. Helping out on an important scientific and community project with some of the greatest people I’ve had the pleasure to meet and work with.

I spent the best three months of my life there in 2009. Diving every day, researching sharks and mantas, and helping a small island community—through the research and its application to conservation and within the local dive tourism industry, but also directly within the community, where the project provides jobs, helped construct housing and where TSRCP volunteers teach marine biology and conservation at the local school.

Life on the island was confronting at first. About 2 km square consisting of a couple of small villages and a few dive resorts (largely foreign owned, but where the island community gets 80% of its income), there is no permanent electricity and no fresh water. The island is powered by petrol generators prone to breakdown and drinking water is imported daily. A simple, largely subsistence lifestyle. I grew to love the island and its people.


TSRCP was started in 2005 by research scientists Simon P. Oliver and Alison J. Beckett to create a baseline of Monad Shoal in the Philippines—primarily concerned with Pelagic Thresher Shark (Alopias pelagicus) cleaning activity as well as the shoal’s coral coverage and general health.

Monad Shoal is about 8 km east of the southern beach of Malapascua Island in the Visayan Sea—an open water seamount with a relatively square dive profile around 21–24m that plunges to 250m, presenting a unique opportunity to observe and record these rarely studied oceanic sharks.

Both threshers and Manta Rays (Manta birostris) frequent the site, as well as a myriad of other pelagic and reef fish. Particularly the various species of cleaner fish that draw the oceanic wildlife to the shoal.

TSRCP is a significant source of environmental, ecological and behavioural research for Pelagic Thresher Sharks, providing research, education and conservation locally, regionally and internationally.

GUE Relationship

Through volunteer divers (including myself) TSRCP became aware of Global Underwater Explorers, a non-profit diver training agency focussed on research, conservation and exploration, whose training methods and techniques are uniquely suited to scientific research diving. In 2009 TSRCP became a GUE affiliated project and now provides all volunteer divers with basic training aimed at perfecting the buoyancy, trim and propulsion techniques necessary for a successful research diver.

Join Us

I encourage any divers out there to volunteer with the The Thresher Shark Research & Conservation Project. My three months there were amazing—peaceful, eye opening and life changing. The most fulfilling ‘work’ I’ve ever done. I can’t wait to be back in 2011.

Depth Gauge Now With More Air Depth

UPDATE: Air Depth and Depth Gauge are no longer available. Check out Gas Manager on the App Store.

I’ve submitted a new version of Depth Gauge to the App Store. Other than being recompiled for OS 2.x backward compatibility, this update brings an enhanced version of Air Depth EAD calculator. The Depth slider’s range is now tied to the MOD of the gas.

Version 1.1 of Air Depth has also been submitted. Other than recompilation for backward compatibility, this is a cosmetic update.


UPDATE: Depth Gauge is no longer available. Check out Gas Manager on the App Store.

Air Depth and Depth Gauge 1.0.1 have finally gone live on the App Store. The biggest change is that both now share a lot of code (in preparation for Depth Gauge 1.1), however the visible changes are:

  1. The Nitrogen slider’s visibility is controlled by a new setting: “Show Nitrogen %”.
  2. New gas icons replace the labels to the left of each slider.
  3. Localización española.

Depth Gauge 1.1 is almost ready for publishing. I’m just waiting on one last piece of localised text and for the resurrection of my MackBook Pro. The big change for 1.1 is the inclusion of Air Depth, allowing you to use both tools from the one application. The free version of Air Depth will of course still exist and could be considered a lite version of Depth Gauge.

Inconsistency Upsets Me

UPDATE: Air Depth and Depth Gauge are no longer available. Check out Gas Manager on the App Store.

UPDATE: I’ve seeded new versions of each app.

So today version 1.0.1 of Depth Gauge was rejected by Apple. Why? Because it contains a disabled slider control. A control disabled on purpose and for good reason. A control included and displayed to the user for good reason.

According to the rejection letter, Depth Gauge was rejected for two reasons. Firstly, it doesn’t do what it claims in the release notes. This is, of course, utterly wrong. It does exactly what it claims.

Secondly, apparently you aren’t allowed to disable or automatically update slider controls. Say what? No, the HIG doesn’t mention that. No, no other documents I can find mention that. Oh and the SDK explicitly supports both things. Which you’d expect, seeing as they’re useful features particularly in the way I’m using the controls.

By far the worst aspect of this is that version 1.0.1 has been in the queue for about three weeks, for only cosmetic changes. That’s right. This functionality was in the original version. It has already been approved.

So what’s a poor boy to do? Send a nicely worded, if mildly abrasive, email to Apple and in the meantime, try to come up with a work around that doesn’t confuse users.