Variations on the Moving Average

Figure 2. Impulse (left), step (middle), and frequency (right) responses for the triangular window.

The moving-average filter is a strong performer in the time domain, but not in the frequency domain. For those cases where you have to work with data for which both domains are important, there are “weighted” versions of the moving average that are… read more

Submitted on 1 February 2016

The Moving Average as a Filter

Figure 1. Smoothing with a moving average filter.

The moving average is often used for smoothing data in the presence of noise. The simple moving average is not always recognized as the Finite Impulse Response (FIR) filter that it is, while it is actually one of the most common filters in signal processing. Treating it as a filter allows… read more

Submitted on 4 December 2015

The Diverging Color Map Is the New Rainbow Color Map

Figure 1. The diverging color map is the new rainbow color map.

I am not a visualization specialist, but I’m convinced that the often used rainbow color map is not well suited for scientific visualization. It might be attractive, but it is not effective. This post mainly introduces diverging color maps as a much better alternative… read more

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Submitted on 16 November 2015

The Hubble eXtreme Deep Field

Figure 1. The Hubble eXtreme Deep Field (XDF).

This image is the Hubble eXtreme Deep Field (XDF). It was created by combining many images taken between 2002 and 2012 by the Hubble Space Telescope. The total exposure time was 22.5 days (almost 2 million seconds), and the image contains… read more

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Submitted on 8 June 2015

Are there Infinitely Many Twin Primes?

Recently, there has been much progress towards proving the twin prime conjecture, one of the great open questions in number theory. There are infinitely many primes, a fact that was already known by the ancient Greek. A short proof, although not the… read more

Submitted on 25 May 2015

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