An HR interview and a technical interview. The HR interview was just to learn about my background, my goals for the coming period and to introduce the company culture and any non-technical details. As for the technical interview, it went as follows. First, a quick discussion of my experience and knowledge in relevant computer science domains (computer graphics, linear algebra, image processing) and technologies (C++, Qt, openGL, VTK/ITK), followed by about an hour or so of technical questions in the technologies/domains that I'm familiar with.