Narendra Ahuja


Narendra Ahuja
Narendra Ahuja

Q: What is your area of expertise?
A: My area is computer vision, a field related to image processing, pattern recognition, sensing, and robotics. The main goal is to automatically understand the contents of images and video--like human vision does routinely--which is why the field is also called “image understanding.” Specific tasks range from very simple and general ones like estimating whether an orange on the tree is ripe to eat or is it within reach, to very complex ones like assigning semantic and possibly subjective labels such as “an attractive outfit” or “that serene view of the skies.”

Q: Give me a brief synopsis of your education and career.
A: My bachelor’s is in electronics engineering, my master’s is in electrical communication engineering, and my PhD is in computer science. My bachelor’s is from the Birla Institute of Technology and Science at Pilani, India, my master’s is from the Indian Institute of Science in Bangalore, India, and my PhD is from the University of Maryland, College Park. I grew up not far from the Taj Mahal, about 30 or 40 miles away. After my PhD, I came to Illinois.

Q: You have been at Illinois since 1979. What do you enjoy most about being here?
A: The longest I have been at any one place is here at Illinois! I never thought I would be here this long. But it’s been one pleasant journey. I like the supportive environment UIUC provides. Urbana-Champaign offers a lifestyle conducive to research. You don’t have to spend an hour and half each way to work. Collegial department, great colleagues, and wonderful students.

Q: Why did you become an engineer?
A: When I was growing up, engineering was one of the most desired professions. If you were doing well in school, you basically went into engineering or medicine. I knew definitely that I didn’t want to become a doctor. I didn’t have any interest in drugging a frog unconscious and dissecting it, which the biology students did regularly. And I don’t like the sight of misery and suffering, although the thought of being able to do something about it was very enticing. Engineering appealed to me on the other hand. I always liked physics when I was in school. Chemistry never really appealed to me as much, nor were my friends passionate about it! I basically made a choice between the wet sciences and the dry sciences, in favor of the dry.

Q: How did you become interested in researching this particular field?
A: When I was thinking about the PhD, we had a professor from Maryland, Azriel Rosenfeld, visit my institute in Bangalore. He was a founder of the field of computer vision. He had come to give a talk, and I thought, this is as good a field as anything I have considered so far. I was also doing my master’s thesis in speech, a reasonably related area. I wrote to him and came to Maryland, and from then on it has been just a tunnel.

Q: What keeps you interested in the field?
A: The challenge posed by the fact that vision is indeed possible. Without a living proof of it in biology, the feasibility of vision would probably have been a controversial notion. It is a formidable challenge to engineering. It will take several generations of many, many people to get even close to the stage where we may duplicate it. If you don’t pay close attention to our ability to see, it seems like an easy task. However, it’s not only difficult by itself, and by that I mean the sensing of light and converting it into something meaningful. But it’s also difficult because it involves lots of bits of knowledge that come from other modalities of sensing and knowledge acquired in the past. So there is this top-down element that regulates how we interpret the sensory signals that are coming in. It keeps me interested because it keeps me busy trying to solve the next problem.

Q: Tell me about a research accomplishment you’re proud of?
A: I have had different periods of emphases on different groups of problems. I have worked on the integration of diverse information sources. We have different cues coming in from the three dimensional world, from texture to stereo to motion to color. So the engineering design question that has run through my work is how to analyze them individually and fuse them together into a holistic construct. In the early ’90s, I had sort of an intellectual accident, and we wound up developing a camera called the omnifocus camera. The whole field of new camera designs has since been an active research area for many researchers across the world. The camera we developed was able to produce a 3D panoramic image with every object in focus along with estimates of depth. We have since developed about eight more cameras. One of these cameras acquires a 360 × 170 degree image, which records a whole hemisphere of an image. You can come back to the recorded video and watch any specific part of it at your leisure. You can break it down by sections of the hemisphere and replay an event that may have occurred. One of these cameras is installed in the main branch of the Busey Bank in Urbana and another one is at work in Missouri. More recently, we have found a way of discovering visual themes present in large sets of images that help unify diverse appearances in terms of a simple explanation.

Q: What do you enjoy most about teaching?
A: Teaching keeps giving you new ideas, in addition to the opportunities to enjoy the moments when you see that the students are learning and understanding, and then using and extending that knowledge. I’ve had roughly 45 PhD students. Often they start with very little, and they falter and run into blind alleys and then suddenly take off. And then they go and do their own things. It’s fun to see them spread their wings and fly. They teach you, too, when you are teaching them. Research comes with teaching, the two are interdependent. Research has a major impact on the contents of the courses and classroom teaching.

Q: What role do students play in your research?
A: They are the central pillars of my research. I enjoy my meetings with them, discussing issues, raising questions, planning investigations, and of course their coming back and reporting the results. It’s a weekly cycle. We look at what happened last week, what this week’s results showed us, and then plan how to move forward.

Q: What award have you won that is the most meaningful?
A: I was probably most influenced by the very first national level award I won in the final year of my high school. I actually received two different awards that year, both from the president of India. For one, I got a scholarship for subsequent six years of my education. The other one was for being a President’s Scout--I think it is called Eagle Scout in the US. I got to shake hands with the president, which is etched in my mind because he was an eminent philosopher besides being the president. The other awards that mean a lot to me are those that come from peers and students because it means that those who are affected by it the most feel that I am doing something worthwhile.

Q: What does the future hold?
A: Computer vision has come an incredibly long way. The theory and the applications are both flourishing. A lot has been accomplished. And of course, cameras are everywhere now. However, compared to what still needs to be done, we’ve only scratched the surface so far. It’s just an extremely large problem. So we can expect a lot of excitement to come our way in this field for a very long time to come.

Q: What else do you hope to accomplish with your research?
A: There are so many problems within apparent reach that I hardly know where to begin the list. One such problem is to improve the content of the raw data acquired by the cameras I mentioned before. I would certainly like to push that up, to a level where they don’t miss anything left or right, near or far, dark or light, coarse or detailed. Another major problem I wish to help solve is extraction and precise characterization of natural structure in images and video. Overall, I want to enhance our understanding of the vision process, and apply it to everyday life in ways that themselves need research, and many of the most creative of which, I am sure, are yet to be discovered.