The process of mocap consist of measuring an objects orientation in physical space relative to said objects prior location, whilst recording or entering the given information in a computer recognizable state. In order to track specific objects effectively, easily recognizable markers are mounted on a mute or mat surface such that there is little interference between the markers or objects and the relative background. Typically the information is sampled using high resolution cameras capable of sampling several times per second; this is done to ensure a fluid transition between each measurable transition.
There are a variety of mechanisms on which these given markers can be mounted but commonly “objects of interest include human and non-human bodies, facial expressions, camera or light positions, and other elements in a scene.(mit)." More often then not live subjects are used as the primary source of the information being acquired such that the relative information can be utilized to modify the given subject into another form.
Currently the two most recognizable transformation present within the public today consist of the transformations of the same individual one Andy Sirkus who in 2001 through 2003 was transformed into one Sméagol also known as Gollum in Peter Jackson’s “Lord of the Rings.” The second transformation occurred in 2005 in which Andy Sirkus was altered utilizing mocap into King Kong the eighth wonder of the world; a forty foot tall giant lumbering ape; this time in Peter Jackson’s remake ok the 1933 masterpiece “King Kong.” Live or real time controllable objects however are not always utilized, “a static object also can be used for motion capture purposes. Perhaps best known of the inanimate motion capture models is the 'Monkey', a 23-inch articulated mannequin with 39 joints, created by Digital Image Design. A Monkey, of course, is different from a live subject in that it provides pose data but no timing information. Dyer, et al., explain that the Monkey provides an easy transition for animators trained in stop motion, since it relies on posed models rather than the direction of live performers.(mit).”
Presently there are four systems utilized to perform mocap in society today, these systems include optical systems, inertial systems, mechanical motion and magnetic systems.
Optical systems use information acquired through the use of image based sensors to triangulate the 3D location of a target relative to one or more cameras accordingly calibrated such that they demonstrate overlapping projections. As the number of subjects, targets or relative area of the recording area expands so does the number of cameras required. The down side to this rendition of motion capture is the fact that rotational data must be inferred due to the fact that there are only three degrees of motion; for instance a hip marker, knee marker, and ankle marker are utilized to determine the angle in which the knee would be resting.Inertial systems are an extremely low cost methodology of performing motion capture since no outside cameras or emitters are necessary to perform this task. Instead the capture technology “is based on miniature inertial sensors, biomechanical models and sensor fusion algorithms. It's an easy to use and cost-efficient way for full-body human motion capture. The motion data of the inertial sensors (inertial guidance system) is transmitted wirelessly to a PC or laptop, where the full body motion is recorded or viewed.(wiki).” A large portion as to why inertial motion capture systems are a positive method for performing mocap is in part to the fact that it allows for the full six degrees of motion to be captured with ease. As a result there are no problems to which computers have to infer as to the given augmentation of specific joints.
Mechanical motion utilizes metal or plastic skeletal structures directly mounted to the performer being tracked. With a function such as this rendition of mocap all the movements are performed in real time and allow for the freedom of being wireless; as a result the performer is privilege to a much larger range motion through which one can operate.
Finally, “magnetic systems calculate position and orientation by the relative magnetic flux of three orthogonal coils on both the transmitter and each receiver. The relative intensity of the voltage or current of the three coils allows these systems to calculate both range and orientation by meticulously mapping the tracking volume.(wiki).” As a result magnetic systems are able to operate with thirty four percent less sensors then that of optical based motion capture systems.
Presently there are large numbers of organizations which focus on motion capture systems; one such company is that of Vicon. Vicon is a United Kingdom and Las Angelous based company with subsidiary branches in India, its three major areas of focus include life science, animation, and engineering. In regards to the animation portion of the company, its most reputable installments include “Troy,” “Van Helsing” and “Star Wars Episode 1: The Phantom Menace.”
It is these aspects that make up process in which motion capture systems or mocap can be performed and utilized within different aspects of business and the entertainment industry.