I had thought of a ‘pixel’ as the smallest unit of digital space, like a tiny square, and that digitial images are made of up such units. This article says it is not that simple and that it is related to Fourier transforms, in which any wave form can be decomposed into the sum of sinusoidal waves of different frequencies.
Perhaps the most unexpected person in this story – at least for readers in the United States – is Vladimir Kotelnikov, the man who turned Fourier’s idea into the pixel.
…Early in his career, Kotelnikov showed how to represent a picture with what we now call pixels. His beautiful and astonishing sampling theorem, published in 1933, is the foundation of the modern picture world.
…A pixel exists only at a point. It’s zero-dimensional (0D), with no extent. You can’t see a pixel.


