Red Nose Day - adjusting for inflation

Every two years, the UK has a fundraising drive, with the complicity of the BBC and many companies, in order to support the needy across the world (and in the UK). It's called Red Nose Day.

And, every two years, there's a big fuss made about how this time people have raised even more money than they did the last time, and how generous people are.
Of course, the British Pound, in common with most currencies, loses value over time (the phenomenon called "inflation"). As a result, it wouldn't be surprising if people seemed to be giving "more" over time, even if the value of what they gave remained constant (or decreased more slowly than inflation devalues the Pound).

So, in the interests of sanity, here's the inflation-adjusted values of Red Nose Day donations, since 2001. The raw values in £ are from Wikipedia's Red Nose Day page (and I start at 2001, since that's when Wikipedia starts listing the total money collected when donations stopped, rather than the total donated by the end of the Red Nose Day itself). The values for inflation adjusted Pounds Sterling were produced by http://www.measuringworth.com/ppoweruk/ , using the Average Earnings method (since it seems reasonable to judge people's donations in terms of the amount they earn, rather than the cost of items).
I include the estimated population in each year (as determined by the World Bank) as an indicator of the degree of population growth. If population goes up, the amount each person needs to donate to match the previous event drops.

2001 - £61m
Inflation adjusted (2009): £79m
Population: 59.1m

2003 - £61.5m
Inflation adjusted (2009): £74.6m
Population: 59.6m

2005 - £63m ?
Inflation adjusted (2009): £70.4m
Population: 60.2m

2007 - £67m
Inflation adjusted (2009): £69.3m
Population: 61.0m

2009 - £82m
Population: 61.8m


So, we conclude that between 2001 and 2007, people progressively donated less to Red Nose Day, only rebounding in 2009 with an unprecedented amount. We don't know how much, in total, the 2011 Red Nose Day will earn yet - but when people claim it's the biggest ever yet, bear in mind the salient lesson of the history of the event. Even when people look like they're giving more, sometimes they're really giving less...

Fun with IR photography

So, I've recently been playing with digital and computational photography. One mechanism for detecting depth relies on projecting light patterns ("structured light") onto a scene, and using the light pattern in the resultant camera image to deduce the 3d location of objects (the pattern lets you determine at what angle rays from the projector intersected the object, and we know what angle rays hit any given pixel in the camera, so trigonometry gives the distance of the object, given the separation between projector and camera). Of course, lighting a scene with a bright light source is distracting to everyone involved, so you ideally need some way to "invisibly" perform the same task.

It turns out that cheap CMOS sensors, of the kind you get in webcams, are actually rather sensitive to infrared light. Normally, there's a filter built into the camera which filters out IR to prevent it from interfering with the visible light imaging you normally want to do... but it's easy to remove it with a screwdriver and a pair of tweezers. Exposed developed film negatives (amongst other things) are pretty opaque to visible light (since they're black), but they're actually transparent to near-infrared light.
If we stick a piece of film negative over our modified webcam, we can then image only the infrared light in the scene... we've made a cheap IR camera.
(This is basically how every security camera, and many "nightvision" scopes, work.)

So, as I don't have a strong IR source at the moment, I couldn't get on with doing structured light work. I did, however, do some experimenting with imaging things in IR with my modified camera (with comparisons to the same objects imaged in visible wavelengths).

Firstly, it appears that cola is pretty transparent to near-IR:



Secondly, some dyes may be black in visible light, but highly reflective to IR:



Obviously, there's a lot of other things you can discover when imaging things in IR (at least some banknotes reveal interesting watermarks, for example), and I might get around to making some more posts in the future.