This is another case of a class project that turned into a little more than a regular assignment.
The story began last fall in MIT’s course 6.810 (Engineering Interactive Technologies), taught by Stefanie Mueller, assistant professor in MIT’s Department of Electrical Engineering and Computer Science. The students, who were mostly undergraduates, were asked to complete a final group project and were assisted by graduate students who assisted Mueller in teaching the course.
The result of these efforts and an accompanying report will now be presented in August. In Vancouver, Canada, SIGGRAPH 2022, “the world’s largest, most influential annual conference for computer graphics and interactive techniques.”
Ticha Sethapakdi, a third-year doctoral student at MIT’s Computer Science and Artificial Intelligence Laboratory, thought carefully about an assignment that could be completed in a couple of months and that would also allow students to use the skills they learned in class. Maybe they could make an instant camera, she thought, but instead of following Polaroid’s lead, it might be fun to make a camera that produced moving images. A cheap and portable device like this, Sethapakdi reasoned, could be a great icebreaker in social situations and, more importantly, open the door to other applications that weren’t immediately obvious to the members of their research team.
In order to stay within their modest budgets, Sethapakdi acknowledged that they would have to choose a simple, low-tech approach that would not require expensive and complex equipment. She used a technique called kinegrams, which was invented in the 20th century. at the end, just before the first cartoons were introduced, and decided that this might be a good way to go.
KineCAM: An instant camera for animated paper photos
In a nutshell, this is how kinegram works. First, you start with several images or shots – say three – of the same subject, such as a butterfly, in different poses. Next, cut each image into horizontal strips of equal width, perhaps 10 in total. You then take these three images and stitch them together on the page to create one “interlaced image” of 30 horizontal strips in total – starting with the top of the first, second and third images strips and so on alternately until the last three strips are laid out in a row. Then you take a “striped overlay” – a separate sheet with transparent stripes – again, 10 in total – the same width as the stripes on the interlaced images. Each transparent strip, in turn, is interspersed with 10 opaque strips that are twice as wide as the transparent ones.
If you then put the two sheets together, place the striped overlay on top of the interlaced image, and quickly move the overlay down, you’ll see the butterfly move between different poses. This is a fairly crude form of animation, although a little more complicated than the cartoons that students in the classroom can create.
But the challenge was finding a way to quickly and easily create kinegrams using a lightweight portable device. And here’s how KineCAM appeared. All of its components, except the batteries, fit into a box that measures 3.5″ x 5.6″ x 1.7″. The parts include a small computer called a Raspberry Pi, an attached video camera (similar to those found in mobile phones), a thermal printer (similar to the one used to print receipts), a camera shutter button, and an LED indicator light, all available off the shelf for less than $100.
As Sethapakdi and her co-authors—Mueller, postdoc Mackenzie Leake, and two undergraduate students, Catalina Monsalve Rodriguez and Miranda J. Cai—explain in their paper, “to create a kinegram, our system records a video for a fixed unit of time and chooses n. shots from it. It then splits the frames into strips of width w pixels, combines them, and combines them into a single image.
“We have to program the system ourselves,” notes Sethapakdi. “The software takes multiple video frames, cuts the images and sends the cut version to the printer. Processing time is extremely fast, taking only about 16 seconds from photo capture to print. Everything is done with KineCAM itself, except for the creation of striped overlays, which are pre-printed on transparency film using a conventional inkjet printer.
According to Sethapakdi, one of the advantages of this approach is that you can go out into the world and make these animated pictures on the spot. Of course, you can also take pictures with your mobile phone, she adds. “But the actual physical receipt is something very attractive and intimate—a one-of-a-kind copy of a particular experience.” And a moving image can capture aspects of that experience that a still photo cannot.
The MIT team believes that KineCAM has applications in computer graphics and rotoscoping, a traditional animation technique. Sethapakdi believes that artists and researchers are likely to come up with interesting ideas themselves. “We’re open-sourcing this project so that others can modify the camera, adapt the code, and build it to do whatever they want.” We are happy to let others explore the possibilities.
She’ll soon be speaking to a target audience at SIGGRAPH 2022. Someone at that conference may have plans for KineCAM that haven’t occurred to its inventors—a prospect Sethapakdi is actively looking forward to.
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