Examples of linear/logistic regression applications I was wondering about super simple applications of linear or logistic regression to signal processing (image processing specifically)?

I'm a math guy that's been asked to explain some mathematical methods to signal/image processing people, and I'd like to be able to use a couple simple examples that are related to their field, but I know little about image processing. So, I'm not looking for anything complicated (I don't know the subject, so the simpler the better; I'm just hoping to find something to demonstrate the applicability of these algorithms).

Thank you for your help!
In image processing all I can think of is using linear regression to fit a plane to the intensity surface of an image, and using logistic regression for some  kind of supervised thresholding...

You might be better off using an example from computer vision instead. For example texture classification or object recognition.