How the Hough transform was invented [DSP History

Where did this transform come from? You may vaguely recall learning that it goes back to a 1962 patent by P.V.C. Hough, though the author suspect very few readers have actually looked at that patent, the title page. If you do, you may be surprised to find that the popular transform used today is not described there. Indeed, today's transform was not a single-step invention but instead took several steps that resulted in Hough's initial idea being combined with an idea from an obscure branch of late 19th century mathematics to produce the familiar sinusoidal transform. The previously untold history of how this came about illustrates how important advances sometime come from combining not-obviously-related ideas. The history perhaps also illustrates that the observation of Louis Pasteur, "Chance favors the prepared mind," remains as apt in the 20th and 21st centuries as it was in the 19th.