Motion Capture Technology Computer Graphics

Computer Graphics

Computer GraphicsMOTION CAPTURING TECHNOLOGYBy- Rohan Patel Email : [email protected]

Name : Rohan PatelEnroll : 140170116038Subject: Computer GraphicsTopic: Motion Capturing TechnologyBy- Rohan Patel Email : [email protected]

Contents INTRODUCTION HISTORY ROTOSCOPING MOTION CAPTURING TECHNIQUE APPLICATIONS CONCLUSIONBy- Rohan Patel Email : [email protected]

IntroductionMotion capture is the process of recording human movement through specialised cameras and mapping them onto a character model.Motion capture technology involves sensing ,digitalizing, and recording that object in motion.also known as Mo-Cap, Virtual theatre, Real time animation or performance capture.Infilmmakingandvideo game development, it refers to recording actions ofhuman actors, and using that information to animatedigital character models in 2D or 3Dcomputer animation.By- Rohan Patel Email : [email protected]

HISTORY

Motion capture was first developed in the late 1970s but it wasnt recognised as a revolutionary animation technique until the mid 1980s when it was eventually used for entertainment purposes.

The technique of ROTOSCOPING was invented byMax Fleischer, dressed in aclownoutfit as the live-film reference for the characterKoko the Clown.

Walt Disney and his animators employed it inSnow White and the Seven Dwarfsin1937.FromSnow Whiteonwards, the rotoscope was used mainly for studying human and animal motion, rather than actual tracing.

By- Rohan Patel Email : [email protected]

Later loony toons, movies like Wizards(1977),The Lord of the Rings(1978),American pop etc were created.

Video games often use motion capture to animate athletes, martial artists, and other in-game characters.This has been done since theSega Model 2arcade game,Virtual Fighter 2in1994.

By mid-1995 the use of motion capture in video game development had become commonplace.

and developer to have its own in-house motion capture studio built into its headquarters


ROTOSCOPINGA rotoscoping is a device that enables animators to trace live action movement, frame by frame, for use in animation.


Classification of motion capture

Mechanical motion captureThe optical motion captureThe magnetic motion captureGenerally motion capture can be classified into three categories :


Mechanical motion captureMechanical motion capture systems directly track body joint angles and are often referred to as exo-skeleton motion capture systems.The sensors are attached to the body of performer and each joints are connected to the angular encoder.


The value of movement of each encoder (rotation etc..) rebuild by a computer that by knowing the relative position encoder can rebuild the movement on the screen using softwareMechanical motion capture systems are real-time system.



Advantages

Offer high precisionDo not depend on external factors such as no. of camerasComputes rotations directlyPortable, unlimited rangeLess expensiveCan capture multiple performances simultaneously


DisadvantagesExternal structure unwieldyCannot change the configuration, i.e., a hand capture cant be used for an armIt is complicated to measure the interaction of several exoskeletons.


2.The magnetic motion captureElectromagnetic Motion Capture is one of the more technical types of Motion Capture relying on transmitters and receivers to track movement. performer would wear several magnetic receivers in which transmitters would tract and calculate movement.Performer wears an array of magnetic receivers which track location with respect to transmitter.12-20 tracking sensors are placed on a captured subject.Tracking sensors output their translation and orientations.Divide into two groups 1. Direct Currant (DC) : Uses square pulses 2. Alternating Currant (AC) : Uses sin wave pulse



AdvantageNo occlusionLess expensive than optical motion capture


disadvantages

Limited rangeSensitivity to metalsCannot perform with multiple actorsCapture volume is limited


3.The Optical Motion CaptureThe capture is based on optical shooting several synchronized cameras

2 to 32 cameras controls by computer

Operating principle is similar to radar


Working PrincipleThe cameras emits the radiation (usually infra red), reflected by the markers(whose surface is reflected by ultra reflecting material) and then returned to same cameras.

These are sensitive to one type of wave length and viewing markers in the form of white spot videos. Checking the information of each camera to determine the position of markers in virtual space.By- Rohan Patel Email : [email protected]



AdvantagesFreedom of movement

High quality capture

High throughput

fast sampling (200 fps at a high resolution)

can capture fast motions

large capture space

can capture many markers


DisadvantagesOcclusion, markers are can be hidden from the camera additional performers will increase occlusion

may be able to add redundant cameras

Marker crossover, which marker are you looking at?

It is more expensive

Extensive post processing (the markers have to be located and identified


APPLICATIONsMotion capture is being used more and more in films nowadaysSome film characters require the use of motion capture, otherwise their animation seems fake.Films that used motion capture technologies are.. Avatar, The adventures of tintin, The avangers, Hulk, Iron man, Kochadaiiyaan etc

Movies/AnimationsBy- Rohan Patel Email : [email protected]

Avatar Is The One Of The Best Film Ever Used The Motion Capture Technology.

To achieve the face expressions, actors wore individually madeskull caps fitted with a tiny camera positioned in front of the actors' faces

This method allows the filmmakers to transfer 100% of the actors' physical performances to their digital counterparts


Video gamesUsed to improve gameplay.Takes the game to the new heights and make more attractive.Very close to real life characters.



MEDICINEEg: gait analysis, rehabilitatition

Sports medicine(eg: injury prevention, performance analysis, enhancement

MILLITARYTracking head movements of pilots in millitary



Thank you..By- Rohan Patel Email : [email protected]

Motion Capture Technology Computer Graphics

Technology

Transcript of Motion Capture Technology Computer Graphics