3D motion capture system is a comprehensive record of object motion in three-dimensional space equipment, according to the principle of different types of mechanical motion capture, acoustic motion capture, electromagnetic motion capture, optical motion capture, and inertial motion capture. The current mainstream three-dimensional motion capture devices on the market are mainly the latter two technologies.
Other common production techniques include photo scanning technology, alchemy, simulation, etc.
Optical motion capture. Most of the common optical motion capture based on computer vision principles can be divided into Marker point-based and non-Marker point-based motion capture. Marker point-based motion capture requires reflective points, commonly known as Marker points, to be attached to key locations of the target object, and uses a high-speed infrared camera to capture the trajectory of the reflective points on the target object, thus reflecting the motion of the target object in space. Theoretically, for a point in space, as long as it can be seen by two cameras at the same time, the location of the point in space at this moment can be determined based on the images and camera parameters captured by the two cameras at the same moment.
For example, for the human body to capture motion, it is often necessary to attach reflective balls to each joint and bony mark of the human body, and capture the motion trajectory of the reflective points through infrared high-speed cameras, and subsequently analyze and process them to restore the motion of the human body in space and automatically identify the human posture.
In recent years, with the development of computer science, another technique of non-Marker point is rapidly developing, and this method mainly uses image recognition and analysis technology to analyze the images taken by computer directly. This technique is the one that is most subject to environmental interference, and variables such as light, background, and occlusion may all have a large impact on the capture effect.
Inertial Motion Capture
Another more common motion capture system is based on inertial sensors (Inertial Measurement Unit, IMU) motion capture, which is a chip integrated package into small modules bound in various parts of the body, the spatial movement of the human link recorded by the chip, and later analyzed by computer algorithms thus transformed into human motion data.
Because inertial capture is mainly fixed at the link point inertial sensor (IMU), through the movement of the sensor to calculate the position change, so inertial capture is not easily affected by the external environment. However, the accuracy of inertial capture is not as good as that of optical capture when comparing the results.