Post on 05-Jan-2016
description
Towards Event-based Animation
By David OziemDepartment of Computer Science
Many thanks to Colin Dalton, David Gibson and Neill Campbell
SRCFE 2003: David Oziem, Dept. Computer Science
Introduction
SRCFE 2003: David Oziem, Dept. Computer Science
Introduction
“A cheap costing for a photorealistic animated film is around £30,000
per minute”
SRCFE 2003: David Oziem, Dept. Computer Science
Problem
Repeated actions.
The standard approach would be to repeat a single action many times. Boring, Unnatural, Easily noticed.
Animating a long sequence would be hugely expensive and time consuming.
SRCFE 2003: David Oziem, Dept. Computer Science
Auto-Regressive Process
Method of modelling sequences.
Learns patterns within a sequence, allowing new sequences to be generated.
Two potential media types: Pixel values (Video clip) Joint rotations (Animated character)
SRCFE 2003: David Oziem, Dept. Computer Science
Campfire
• Example of a video texture.
Eigenpath & Original clip
SRCFE 2003: David Oziem, Dept. Computer Science
Generated Sequences
Plots of the motion through the eigenspace
SRCFE 2003: David Oziem, Dept. Computer Science
Generated Video Clip
Generated SequenceOriginal Clip
SRCFE 2003: David Oziem, Dept. Computer Science
Barman
SRCFE 2003: David Oziem, Dept. Computer Science
Barman
The barman. Very short clip, only 200 frames, Does not loop fluently.
SRCFE 2003: David Oziem, Dept. Computer Science
Generated barman
Generated version of the barman scene
SRCFE 2003: David Oziem, Dept. Computer Science
Horse Gait (States)
Not all motion continually repeats itself in a Gaussian distribution,
Transitions between states may occur.
SRCFE 2003: David Oziem, Dept. Computer Science
Crowd Scene (Event-driven)
State changes are driven by events.
A KLT (Kanade-Lucas-Tomasi) feature tracker was used to find the average vertical velocity in each of these 16 blocks.
SRCFE 2003: David Oziem, Dept. Computer Science
Crowd scene (Sequence)
The first 3 modes against time
SRCFE 2003: David Oziem, Dept. Computer Science
Crowd scene (Generation)
An ARP creates an array of motions which are Completely unlinked, Not event driven.
SRCFE 2003: David Oziem, Dept. Computer Science
Crowd scene (Generation)
The low frequency component used to dictate the general path of the primary mode.
SRCFE 2003: David Oziem, Dept. Computer Science
Generated crowd
Event occurs in all models at the same moment. The crowd stands at different speeds and for varying
durations.
SRCFE 2003: David Oziem, Dept. Computer Science
Future work
Other forms of ARP’s. Including; ARX Auto-Regression with eXternal signal. TAR Transition Auto-Regression.
Use of Hidden Markov Models to drive state changes.
SRCFE 2003: David Oziem, Dept. Computer Science
Summary
There are massive potential savings of generating sequences.
Natural motion is does NOT repeat perfectly.
Event driven state changes are difficult to model but it is possible.
ARP’s can generate new clips given that there is no change of state.
SRCFE 2003: David Oziem, Dept. Computer Science
Questions?
oziem@cs.bris.ac.uk http://www.cs.bris.ac.uk/home/oziem/