Archive for month: August, 2009

Cheap Arduino Wireless Communications

August 30, 2009 | General | By: Mark VandeWettering

As part of my slow, arduous march toward doing a high altitude balloon launch, I acquired some super cheap wireless modules from Sadly, I haven’t had time to play with them much, but here’s someone who has. I am more interested in using these tiny transmitters as back up beacons, but the information is […]

Micro-Rendering for Scalable, Parallel Final Gathering

August 29, 2009 | Computer Graphics, General | By: Mark VandeWettering

Thanks to Kevin Bjorke for pointing out this paper. It combines a couple of interesting features to create a point-based renderer that efficiently uses the GPU to render scenes with global illumination. I’ll have to read it more carefully when I have time. Micro-Rendering for Scalable, Parallel Final Gathering. httpv://

A little statistics puzzle…

August 27, 2009 | General | By: Mark VandeWettering

I hand you a deck of cards, which you shuffle, and deal me a random 5 card poker hand. I announce that I have an ace in my hand. What are the odds that I have a second ace in my hand? Now, play the game, and deal me another hand. I announce that I […]

Computer Vision: Algorithms and Applications

August 25, 2009 | General | By: Mark VandeWettering

Microsoft researcher Richard Szeliski has a text on computer vision available for download. Szeliski has written countless papers on computer graphics, including lots of papers on creating panoramas from images. Good stuff, bookmarked for later consumption.

The telescope turns 400 today…

August 25, 2009 | Astronomy | By: Mark VandeWettering

On this day in history, 400 years ago Galileo Galilei demonstrated his telescope to a group of Venetian lawmakers. In March of the following year, he would publish his most famous work, Siderius Nuncius (commonly rendered in English as The Starry Messenger). This invention ushered in the modern era of astronomy, and quite literally changed […]

Another HTML 5 video test…

August 24, 2009 | General | By: Mark VandeWettering

This is just a test. If you are running Firefox 3.5, you should get a video window that allows you to watch a Superman cartoon encoded in Ogg Theora. If you aren’t running it, but have a Java enabled browser, you should get an applet which plays the same video. If you have neither, you […]

A simple, short puzzle

August 24, 2009 | Puzzles | By: Mark VandeWettering

Here is a simple puzzle that came from Martin Gardner’s The Colossal Book of Short Puzzles and Problems. Here we see ten circles arranged in the classic triangle bowling configuration. The question is “what is the minimum number of circles that can be removed such that there is no equilateral triangle formed by the centers […]

Random bits…

August 18, 2009 | Math | By: Mark VandeWettering

Well, pseudo-random, but reportedly cryptographically strong. 01110 10011 01100 01000 11101 11001 11010 10011 00000 10011 11111 11001 10101 11100 10011 10110 01010 01100 01000 00010 11110 01100 11010 11000 00011 11111 10001 00111 01011 00101 00011 00111 01000 11111 10011 01001 10000 10101 10001 01011 11111 00100 11010 10000 00110 11111 10111 11011 00011 […]

Something fishy going on here…

August 17, 2009 | Computer Graphics, My Projects | By: Mark VandeWettering

Another of my attempts to make pictures from volume data…

HF Reference Material

August 16, 2009 | Amateur Radio | By: Mark VandeWettering

From a thread on, here’s a nice list of 1000 utility stations which broadcast on HF. Nifty. HF Reference Material

FM receiver from the Atmel AVR 2004 Design Contest

August 16, 2009 | Amateur Radio | By: Mark VandeWettering

Just a place holder for a link to an interesting FM receiver that could be used for receiving NOAA polar orbiting satellites. It was an entrance in the Atmel 2004 Design contest. Very neat. Atmel AVR 2004 Design Contest

More volume rendering…

August 15, 2009 | General | By: Mark VandeWettering

Well, I thought I had the rotation thing figured out, but I still seem to be missing something. But I did muck around a little bit, thresholding the image in a couple of different ways, making the pair shown below. The one on the left contains mostly the bones, with all the flesh transparent. The […]

Volume Rendering: Going boldly where all have gone before…

August 12, 2009 | Computer Graphics | By: Mark VandeWettering

Okay, this is a bit gruesome, but I’ve been dusting off some old papers that I never really understood on Fourier Volume Rendering, and testing my understanding by writing some simple code that takes in a volume dataset and uses the fast Fourier transform to convert it into simulated X-ray pictures. The data set that […]

WSPR signals heard from E51EME

August 12, 2009 | General | By: Mark VandeWettering

I still check my WSPR station logs each morning when I wake up. This morning I spotted the callsign E51EME, coming from grid square BG08. I’ve come to realize that many of these spots which include only a four element grid designator are spurious bad decodes, and I didn’t recognize the prefix (I’m not much […]

SumbandilaSat launch scheduled for Sept 15

August 11, 2009 | Amateur Radio, Amateur Satellite | By: Mark VandeWettering

I haven’t been playing with the LEO sats much lately, but it’s good to hear that the South African amateur satellite SumbandilaSat is nearing launch. It has a 2m/70cm FM transponder, and a voice beacon. I’ll try to get more information as the launch date gets closer. SumbandilaSat launch scheduled for Sept 15