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.

Rosetta

Rosetta and Philae at comet [image: ESA–J. Huart]

There’s a truly cool deep space mission that I need to bring to your attention: Rosetta. Visit ESA’s Rosetta page for details. Rosetta is an ESA (European Space Agency) mission. It will be the first spacecraft that… read more

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Submitted on 5 June 2014

Compressed Sensing

Compressed sensing example with stars. Original image (left), measurements (middle), reconstructed image (right).

Compressed sensing (or compressive sensing) is a relatively new technique that is becoming more and more important in image and signal acquisition. The term originates from image compression, where, in the classical workflow, images are first… read more

Submitted on 1 June 2014

How to Create a Simple High-Pass Filter?

Low-pass (left) and high-pass (right) filters

How to create a simple high-pass filter, given a cutoff frequency and a transition bandwidth? A high-pass filter can be created by building a low-pass filter first, and then using spectral inversion to convert it into a high-pass one. Starting from the… read more

Submitted on 27 April 2014

How to Create a Simple Low-Pass Filter?

Normalized windowed-sinc filter

How to create a simple low-pass filter, given a cutoff frequency and a transition bandwidth? A low-pass filter is meant to allow low frequencies to pass, but to stop high frequencies. Theoretically, the ideal (i.e., perfect) low-pass filter is the sinc filter. The sinc function is defined as… read more

Submitted on 15 April 2014

Introducing Clippy!

Clippy

I’ve decided to introduce the world-famous Clippy to improve the interactivity of this site. After all, who am I to doubt the wisdom of Microsoft when they introduced it as the friendly helper that it is, and that already in 1997. You might be skeptical about this, but trust me, it’ll be cool! I haven’t decided yet whether… read more

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Submitted on 1 April 2014

The Clustering Illusion

The clustering illusion is the human tendency to expect random events to appear more regular or uniform than they are in reality, resulting in the assumption that clusters in the data cannot be caused by chance alone. An important example of this is that the stars in the night sky seem clumped together in some regions, while… read more

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Submitted on 5 March 2014

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