After explaining how to create windowed-sinc low-pass and high-pass filters, I have made a tool that allows you to create your own custom versions of these filters, and download the resulting filter coefficients. Go to the tool. At this time, the tool is limited to the (very basic) design method from the mentioned articles, but that’ll change in the future! read more
This is the personal site of Tom Roelandts. I’m trying to whet your appetite for science with this thing. My education and interests show through, of course, since I focus on stuff that I feel confident writing about. The site used to be solely about the photos, and I still think the thumbnails page is rather cute, but the emphasis has clearly shifted towards the articles lately.
Using modulation in radio communications is unavoidable. The simplest modulation technique is Amplitude Modulation (AM), where the amplitude of a carrier is varied according to the message that is to be transmitted. A carrier is… read more
The famous “Wow!” signal is a radio signal that was received on 15 August 1977 as part of the SETI program. After all these years, it is still the most tantalizing candidate for being a true interstellar signal. Its name comes from the manually written word “Wow!” on… read more
This is the second of a two-part article on the PDART algorithm. It explains most of the nitty-gritty details. The PDART algorithm needs two extra input parameters to do its magic, a threshold and a gray level. After each SIRT iteration, each pixel of… read more
This article is a bit of an experiment. In it, I’ll try to explain PDART, an example of current algorithm research in computed tomography (PDART was published in 2011). What the algorithm does is, in a nutshell, a SIRT reconstruction with intermediate… read more
At first sight, this image has nothing to do with my site. I have not posted it or mentioned it. The picture is real, by the way, it is not “Photoshopped”. It is from TV coverage of the Scottish Open golf tournament in Aberdeen, and the effect is caused by atmospheric refraction. But the details of… read more