Special high-speed cameras are placed around the capture stage as to best see the actor's performance. High quality motion capture requires an equally high quality setup. The sample was written in Matlab and is available for download. I have implemented a small one-dimensional sample of the marker detection and tracking algorithm that I will use as an example later on. Post-Process Editing - Connecting the data to a simulated character skeleton.Pre-Capture Setup - Preparing the stage and the subject for useĬapture & Data Acquisition - Tracking subject movement and building a 3D representation.Roughly we split the entire process into three stages: We focus mainly on the process of building the system and actually capturing the data, leaving the animation aspect of OMC to others. This project is an exploration into the inner workings of an Optical Motion Capture system. In the remainder of this paper, we focus on Marker-based OMC. In the special effects industry, Marker-based capture is favored for is accuracy over the convenience of Marker-less tracking. Instead, the actor's silhouette is viewed from different angles, and is used to reconstruct the entire 3D body of the actor. Alternatively, "Marker-less" OMC tries to accomplish the same task without the use of special tracking devices. Recording the positions of these markers throughout the range of the motion, allows us to determine the position of the actor's body at any given time.
Motion capture camera software#
Because of their reflectivity, these markers can easily be recognized by software in the camera. In "Marker-based" OMC reflective markers are placed on the actor's body. Just like binocular vision allows humans to see the world in three dimensions, the use of two or more cameras observing the same subject allows us to rebuild that subject in 3D. OMC uses a number of special cameras that view a scene from a variety of angles. With a "virtual camera" and OMC, directors can move through a CG scene as easily they could a real scene with a real camera.
James Cameron on the virtual set of Avatar. This gives a director an immense amount of creative control when it comes to working with CG. Using OMC, Cameron was able to hold a "virtual camera" in hands, and see how the scene changed as he physically moved the camera through it. Most of the vast landscapes in Avatar were completely computer generated. Motion Capture can also provide a means for a director to better visualize CG scenes.
This brings a greater feeling of life and reality to characters that would be traditionally hand animated. From animated family films, like 2009's 'A Christmas Carol', to live action blockbusters such as James Cameron's 'Avatar', OMC is used to capture the nuisances of an actor's performance and transfer them to an animated character. Today, OMC is used extensively in animation and special effects for major motion pictures. These views are then used to reconstruct the movement in 3D, where it can then be applied to a computer model. Optical Motion Capture (OMC), one such method for turning real-life movement into digital data, uses a number of cameras to film a subject from different views. By the late 1980's and early 1990's, new methods of capturing a subject's motion digitally were being created. Early in the 20th-Century, animators found they could take a film of a moving subject and copy it to a cartoon by physically tracing each frame of the movie, a process called Rotoscoping. Despite an artist's best intentions, human movement is simply to complex to draw by hand.
Traditional animation techniques often fail to accurately capture real human movement.
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