I started writing a post today about the ConvexImage property returned by regionprops. But I got sidetracked along the way, and this post turned into a description of how to overlay a pixel grid... read more >>

"Why do you have M&Ms on your desk?" my friend Nausheen wanted to know. Well, the truth is, for playing around with color images, M&Ms are simply irresistable. url =... read more >>

A reader asked in a blog comment recently why a vertical line (or edge) shows up in the Fourier transform of an image as a horizontal line. I thought I would try to explain this using the... read more >>

The Image Processing Toolbox function regionprops gives you measurements of shape-based measurements of image regions. It's pretty useful, and I have shown many examples of it on this... read more >>

One of the discrete-time Fourier transform properties that many people learn is that if a sequence is conjugate symmetric, , then the Fourier transform is real. Therefore it... read more >>

In my Fourier transform series I've been trying to address some of the common points of confusion surrounding this topic. For today's espisode I want to look at how to use the fft... read more >>

OysterEngineer (I love that name!) asked some interesting questions in response to my last Fourier transform post, which concerned the relationship between the discrete-time Fourier transform... read more >>

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One challenge of teaching Fourier transform concepts is that each concept can be (and is) interpreted and explained in many different ways. It isn't always obvious how the different... read more >>

Many of you were onto me immediately last week. I asked you to estimate the frequency of the sampled cosine signal below, and readers quickly chimed in to guess that this question was... read more >>