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Lecture

Posture Reconstruction: Full-Body Interaction

In course

CS-444: Virtual reality

The goal of VR is to embed the users in a potentially complex virtual environment while ensuring that they are able to react as if this environment were real. The course provides a human perception-action background and describes the key programming techni ...

Description

This lecture covers the background on full-body motion capture, posture reconstruction techniques such as Analytic IK and Jacobian-based IK, collision avoidance, and examples of full-body interaction. It explains the process of system calibration, camera registration, and full-body tracking. The comparison of Analytic IK and Jacobian-based IK methods is discussed, along with their advantages and drawbacks. The concept of priority levels in Jacobian-based IK for handling redundancy and conflicting tasks is explored, with demonstrations on interactive goal movement. The lecture also presents a low-cost Analytic solution for full-body scale motion capture and the use of hybrid techniques like CCD and FABRIK. Various concepts like forward kinematics, inverse kinematics, and posture variation are explained in the context of full-body motion capture.

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Instructor

Ronan Boulic

I come from Brittany, France, where I have completed my PhD degree in Computer Science in 1986 from the University of Rennes, France, at the INRIA-IRISA research institute. I also received the Habilitation degree from the University of Grenoble, France, in march 1995. I was hired in 1989 as First Assistant in the VRLAB, I became scientific collaborator, and senior researcher. I'm presently Senior Scientist (MER) and leader of the Immersive Interaction research Group (IIG). I'm co-author of around 150 research papers among which 43 appeared in international peer-reviewed journals. I have contributed to multiple SNF projects and EU projects. Please check iig.epfl.ch for more details.

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Related concepts (27)

Inverse kinematics

In computer animation and robotics, inverse kinematics is the mathematical process of calculating the variable joint parameters needed to place the end of a kinematic chain, such as a robot manipulator or animation character's skeleton, in a given position and orientation relative to the start of the chain. Given joint parameters, the position and orientation of the chain's end, e.g. the hand of the character or robot, can typically be calculated directly using multiple applications of trigonometric formulas, a process known as forward kinematics.

Forward kinematics

In robot kinematics, forward kinematics refers to the use of the kinematic equations of a robot to compute the position of the end-effector from specified values for the joint parameters. The kinematics equations of the robot are used in robotics, computer games, and animation. The reverse process, that computes the joint parameters that achieve a specified position of the end-effector, is known as inverse kinematics.

Robot kinematics

In robotics, robot kinematics applies geometry to the study of the movement of multi-degree of freedom kinematic chains that form the structure of robotic systems. The emphasis on geometry means that the links of the robot are modeled as rigid bodies and its joints are assumed to provide pure rotation or translation. Robot kinematics studies the relationship between the dimensions and connectivity of kinematic chains and the position, velocity and acceleration of each of the links in the robotic system, in order to plan and control movement and to compute actuator forces and torques.

Kinematics

Kinematics is a subfield of physics, developed in classical mechanics, that describes the motion of points, bodies (objects), and systems of bodies (groups of objects) without considering the forces that cause them to move. Kinematics, as a field of study, is often referred to as the "geometry of motion" and is occasionally seen as a branch of mathematics. A kinematics problem begins by describing the geometry of the system and declaring the initial conditions of any known values of position, velocity and/or acceleration of points within the system.

Kinematic chain

In mechanical engineering, a kinematic chain is an assembly of rigid bodies connected by joints to provide constrained motion that is the mathematical model for a mechanical system. As the word chain suggests, the rigid bodies, or links, are constrained by their connections to other links. An example is the simple open chain formed by links connected in series, like the usual chain, which is the kinematic model for a typical robot manipulator. Mathematical models of the connections, or joints, between two links are termed kinematic pairs.

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