I liked Golan Levin’s overview of the techniques for computer vision. His exposition allowed me to look at the complex problem with new eyes, and made me realize that simple algorithms may be used for a complex effect – frame differencing, background subtraction, color tracking, and thresholding; all of which we have mentioned in class. At the same time, I liked Levin’s mention of the state-of-the-art techniques, and everything in between. I felt like that provided perspective to the field and showed me that despite its accessibility, computer vision can also answer some complicated questions. (Consider the question of gaze direction detection – not only does it require tracking of one’s pupils; the orientation of the face in 3D space is also required, as is some notion of depth in the field of view.)
I learned the most from Levin’s emphasis on the importance of physical conditions when using computer vision. His insistence that the assumptions of the different algorithms be taken into account when designing the interactive art piece made me realize how prevalent these problems are. At the same time, it illustrated how impossible-to-solve software questions (e.g. how can I know whether this dark spot in the frame is a person’s hair or a black area on the background wall that just happens to be next to the person’s head?) can be solved by preparation of the scene (e.g. perhaps just use a green screen behind the person. Or the person can be illuminated by sharp light and stand in front of a black wall.).
I have one complaint about the article – despite all of its talk about bringing a fresh, artistic, set of perspectives to computer vision, four out of the six examples revolve around surveillance. Although it is an important topic – and perhaps very natural, given the fact that computer vision systems must necessarily use a video-recording device – I would have appreciated to be exposed to more variety, to get my creativity going in more directions than just surveillance.