Applied online. Received an email three months later asking availability to interview on-site. Scheduling was coordinated with HR, who paid for airfare, hotel, and rental car. However, HR would not explicitly state who would be conducting the interview on the other end, so it was not possible to research whom might be interviewing you.
As part of the interview, I was asked to give a seminar on a topic of my choice, which should last about 45 minutes + time for questions / discussion.
During the interview, I first met with an HR rep, who went over benefits with the company. Next, I met briefly with the group manager, before starting my seminar. Following the seminar, I spoke with two other members of the group for about 30 - 45 minutes (one for lunch in the cafeteria), and the assistant group manager for about 15 minutes. The interview itself lasted about 4 hours.
I wasn't asked technical questions per se, but a general working familiarity with techniques for image processing, and pattern recognition were expected. For example, being able to communicate familiarity with Bayesian classification, SVM, etc. Other general questions include the kind of work you would be interested in.
Prior to this interview I had previously done four on-site interviews for full-time positions and this one appeared to be the least scheduled (in terms of itinerary and number of people to meet). Everyone seemed to be really busy and did not have much time to meet.
After a week I received an email from the HR rep I met with on-site stating that the group does not have further interest in my candidacy and will continue to interview other candidates as they see fit.