Motion capture technology or Mocap started off 105 years ago as rotoscoping, when animator Max Fleischer (i.e., creator of Popeye and Betty Boop) traced over motion picture footages frame-by-frame on a glass-topped table to generate realistic and continuous movements. Disney was the first company to adopt this technique and produced a full-length animated film “Snow White and the Seven Dwarfs” in 1939.
During the Cold War era, animator Lee Harrison III pioneered real-time motion capture by asking actors to put on bodysuits that are lined with potentiometers which would register and enliven the way they moved. The analog electronic animation method was gradually consumed by more precise and detailed digital images in the 1980s but overall, Mocap remained elaborate and expensive. The turning point probably came in the early 2000 when Mocap was used in live-action movies; in the creation of the character Gollum in the Lord of the Ring trilogy.
Today, Mocap requires actors to put on spandex suits that are covered with ping-pang ball-like tracking dots to denote their relative positions in computer generated image (CGI) models. Positions and distances between these dots are recorded so that movements from specific parts of the body can be mapped.
When Mocap meets rehab
Researchers from the Motion Analysis Lab (MAL) at the Spaulding Rehabilitation Hospital in Boston have been studying the use Mocap on patients with mobility disorders as a result of stroke or other medical conditions like cerebral palsy, Parkinson’s disease or traumatic brain injuries.
One of the patients, Bill Gramby suffered a stroke 10 years ago which paralyzed the left side of his body. He is able to walk and move again only after an extensive amount of rehabilitation. According to Paulo Bonato, Director of MAL, it’s common for stroke patients to experience difficulties in using the part of their body that is opposite to the affected hemisphere in the brain. As such, the research team would place reflective markers, those that were used in Mocap, to evaluate patients’ movements and determine how much do they deviate from the norm.
These markers are tracked by infrared cameras; “the same type that was used to gather data for ‘The Polar Express’. Exactly the same”, Bonato told Stat. The research team will then recommend the best treatment option to the patients based on the analysed results, so that they can effectively regain their full mobility. Some of these treatment options can range from traditional orthotics to an exoskeleton. “Being able to advance what we’re doing here technology-wise, and combine that with advances in biology, that is what it’s going to allow us to get patients to regain their quality of life after a stroke or traumatic brain injury” Bonato adds.