Many enjoy the warmth, Vikings prefer the coolth


A sinogram of the Shepp Logan phantom

The Radon transform plays an important role in computed tomography since it describes how the raw data are collected. As the x-ray tube rotates around the gantry, the detectors opposite measure the x-ray projections through the object, producing a sinogram, which is effectively the Radon transform of the image. This video demonstrates how the sinogram is created by rotating the digital phantom <as opposed to rotating the x-ray tubes around a real object> and taking projections at each angle. The matlab code and original video were created for a section of a graduate course I taught at UBC.

Are reusable coffee mugs truly an environmentally sustainable alternative?

pic: travel mugA commonly held belief is that reusing a travel mug, such as a mixed plastic and stainless steel vacuum sealed design, is better for the environment than disposable cups, generally made of paper, with a wax-type lining inside and a thin plastic lid.

Natural resources are required to make both of these items. The major component of one is a non-renewable resource - metal, and the major component of the other is a renewable resource - paper. While the paper cups are generally thrown away immediately, the travel mugs eventually end up discarded as well, after being lost or damaged.

Photos of CRT TVs shutting down

pic: CRT TVs shutting downSome awesome photos of CRT TVs powering down. Cathode Ray Tube TVs fire electrons at the fluorescent screen, creating the images that we see. Electromagnets steer the electrons in a raster-fashion across the screen too fast for us to perceive. When the power is shut off, the electrons don't stop immediately, and a latent image decay can be seen, although distinct patterns are generally too short-lived to notice. Of course, this process can be photographed, with some interesting results.

I moved to Kelowna

pic: Interior Health BC logoI moved to Kelowna, starting a job as Medical Physicist/Radiation Safety and Quality Control Lead for Diagnostic Imaging in Interior Health.

You can still contact me using the email address on this site <scroll to the bottom>.

What will happen to Christiania?

Denmark ruling could end hippie conclave. I have a personal interest in this story because of a scary experience I had in Christiania when I visited Denmark. I have copied the previous post verbatim from my old blog <which could disappear at any time!> and pasted it below.

ReviseMRI interviews Wolfram Alpha

This interview is a lot of fun to read. Some of the questions are serious, like "What is MRI", but others are more humorous:

   RevisingMRI: Has that got anything to do with a flux capacitor?
   Wolfram|Alpha: Power required to operate the flux capacitor in the DeLorean DMC-12 time machine: 1.21 GW. Unit conversion: 1.21×109 W (watts) ≡ 1/10 x power of space shuttle at launch.

Wolfram Alpha's answers are genuine, and if you ask the same questions today, you will get the same answers.

A Relationship with Communication Technologies

Long distance relationships have become much shorter. Historically, communicating over long distances was either prohibitively expensive when using the telephone, or had long intermittent delays when using the postal system. The way we communicate with each other changed rapidly as internet technologies matured. My wife and I have known each other for the past 16 years and we have benefited from the evolution of internet-based communication technologies – especially when we were separated by long distances. Our relationship has been better served by communication technologies that have made long distance relationships shorter.

And another thing .... - by Eoin Colfer

pic: and another thing by eion colfer hitch hiker's guide to the galaxyI have been reading And Another Thing ... by Eoin Colfer, the sixth installment of Douglas Adams' Hitch Hiker's Guide to the Galaxy trilogy. The title is really telling of the content, the storyline is constantly being interrupted by afterthoughts disguised as 'Guide Notes'. I eventually discovered that skipping the Guide Notes entirely makes the story flow much better, and I have not missed anything important as far as I can tell. But what really kept me reading is that 'Thor' shows up a lot. There is something about Norse Mythology, or at least Colfer's take on it, that keeps me interested.

Billy Bishop goes to War

I watched the Canadian musical Billy Bishop goes to War on CBC last night. It was a marvelous two man production about a Canadian ace fighter pilot from WWI, written and performed by John MacLachlan Gray and Eric Peterson.