interview questions for DSP engineer
When I interview people, my questions depend a lot on the CV they've submitted. 

If they're fresh from university, I am much more interested in whether they have ever heard of some of the basic image processing concepts: What is their definition of noise and background? What does a Gaussian filter do? And of course, I want to know if they know how to program as opposed to hacking together a last-minute solution for homework. 

If they claim to be more experienced, I want to know how well they know what they're talking about. What's their opinion on supervised vs. unsupervised segmentation? What are good tracking algorithms, and why? What informs their choice of a filtering algorithm? How do they deal with stochastic data? And of course, do they know how to program?

Finally, I'm always happy to find out that they did some research into the topic ahead of time, even if they just read my papers and totally misunderstood them. I can always teach them knowledge, but it is hard to teach effort.