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More fun with Triggertrap

I’ve added a couple of timelapses to Youtube this week, both made with Triggertrap here in Edinburgh.

The first is a capture of Bruce Munro’s Field of Light installation currently at St Andrew square. This was my first experiment with the ‘bulb ramping’ approach, of extending the shutter speed as the timelapse progresses to compensate for falling light as the sun sets. It’s a bit rough around the edges due to some technical limitations and having to guess at appropriate settings, but works reasonably well at compressing the hour around sunset into a minute. You can see Field of Light until April 27th.

The second is a collection of timelapses from the construction of a giant mathematical sculpture. Innovative Learning Week at the University of Edinburgh gives students and staff alike a chance to branch out from their usual lecture schedule and try something different, and this event organised by Julia Collins from the School of Mathematics was a UK first. Involving a team of 20 people, nearly 11,000 pieces of zometool, over six hours of construction time and several extra large pizzas, we were able to built a ‘giant 4D buckyball’, or more formally, a cantitruncated 600 cell. You should be able to go and see this at Summerhall until we need the pieces for something else – probably the Edinburgh Science Festival around Easter – and I’ll try to write more about the mathematics over on Modulo Errors in due course.

(For both videos, you may be better off viewing in full HD.)

Travel 2013

Map of my flights 2013

I took more flights (19) in 2013 than any other year – as many as in the first 24 years of my life combined – but my total mileage (17,327) was actually down about 20% compared to 2011 and 2012. This was largely due to returning to Scotland; with most of the other places I spend my time in the UK being in the South of England, it’s just easier to fly (I’ve long since given up worrying about my carbon footprint).

More interestingly, I visited a few international destinations, all covered in one way or another in the trip reports I filed for FlyerTalk:

  • California Oneworld / Hilton status-running between San Diego, Los Angeles and San Francisco, plus the Joint Math Meetings
  • Italy Cashing in my Hilton points for a taster of the Waldorf Astoria Rome Cavalieri
  • Switzerland Completing the IHG ‘big win’ challenge, attending a Marian Call concert, and visiting CERN

As always, there are corresponding photo galleries which you can find on flickr.

As those reports more than hint, my obsession with airline and hotel ‘travel hacking’ took full form this year. In all, I collected over 100,000 avios and almost 90,000 IHG Reward Club points; made significant status with BA and Hilton; cashed in points for a luxury hotel, a long haul business class flight, and six domestic / european legs; and racked up 37 hotel nights. For both financial and time reasons I’m not sure what opportunities I’ll have for travel in 2014, but that might just force me to put even more effort into this strange hobby!

Space-time manipulation (with buses)

I’ve been continuing my adventures in image manipulation with Matlab, taking the opportunity to play with a technique I’ve been interested in for a long time – ‘slit scan’ or ‘strip’ photography. A very brief (but rather maths-y) explanation of what’s going on in the clip above would be the following:

Let a video be defined by T frames each of dimension X-by-Y. Then the pixel value to be displayed at location x,y at time t is simply V(x,y,t) for some 3-dimensional array V; so the kth frame corresponds to the 2-d image Fk given by the plane T=k. But we may consider other planes to generate frames; by fixing a horizontal position X=k individual frames are images given by (t,y)=V(k,y,t) and iterating through these gives a new video V’(x,y,t)=V(t,y,x).

If that tells you everything you need to know, you can look at a couple more examples here and (more abstractly) here. Otherwise, read on for a fuller explanation!

Continue reading Space-time manipulation (with buses)


Having finally dragged myself into the smartphone age I was at last able to get set up with the mobile version of TriggerTrap, a timelapse gizmo created by some friends of mine. I already had a starting project in mind, to capture the antics of my Roomba.

Having recently returned to Edinburgh for an MSc, I find myself studying Matlab for the first time in a decade. I always feel that the best way to familiarise yourself with a programming language is to have a goal in mind, and I remembered from a JMM talk that Matlab can be used for image processing. So whilst I’d normally reach for python to tackle an unfamiliar task, on this occasion I took the rather circuitous route of Matlab, processing and some video-editing tools.

Continue reading RoombaTrap

California, January 2013

Golden Gate Bridge, on Flickr

I got this year’s travel off to a strong start, spending a fortnight flitting about California. The official reason was academic, as I attended and presented at the Joint Mathematics Meetings in San Diego; I pulled out some mathematical highlights from that over on Modulo Errors. But I also took the opportunity to engage in a `status run’ with British Airways and Hilton Hotels, securing silver and gold tiers in their respective loyalty programmes. As such I racked up close to twelve thousand miles in the air, and stayed at six different hotels, variously visiting London, San Diego, San Francisco, Los Angeles and Coronado. For those interested in the minutiae of such a project, I produced a lengthy report for the FlyerTalk forums. And of course, I took a fair few photos along the way, which have been sifted down into a collection of flickr galleries.