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This presentation explores a novel predictive collision avoidance model designed for pedestrian simulation, presented by Ioannis Karamouzas and team. The method leverages force field approaches to predict potential collisions, allowing for smooth, energy-efficient, and visually pleasing pedestrian motions. It iteratively computes evasive forces, accommodating complex environments. The presentation covers previous works, the proposed method, implementation details, experimental assessments, and future developments in group path planning, highlighting advancements since the introduction of the model.
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A predictive Collision Avoidance Model for Pedestrian Simulation Author: IoannisKaramouzas et al. Presentedby: Jessica Siewert
Content of presentation • Previous work • The method • Implementation • Experiments • Assessment • Developments since
Introduction – Previous work • Dynamic potential-field approach (too general) • Corridor-Map-Method • Helbing Social Force Fields • Example-based (too expensive)
Introduction – Now we want… • Anticipation and prediction (so in advance) • Deal with large and cluttered environments • No constant change of orientation, pushing each other and moving back/forth
Introduction – We got… • Reynolds unaligned collision avoidance • => Feurtey predicts potential collisions within time and resolves by adapting speed and trajectory • => Paris et al. Anticipative model to steer • Shao and Terzopoulos: Reactive routines to determine avoidance maneuvers.
Introduction – We got… • Van den Berg Reciprocal Velocity Obstacle • Pettré et al. Egocentric model for local collision avoidance
Introduction – Our method… • Based on force field approach • Early avoidance hypothesis, anticipation/prediction • Energy-efficient motions • Less curved paths • Smooth natural flow • Oscillation-free
Introduction – Contributions… • Force field method based (Shao, Berg, Pettré don’t) • Easier in formulation and implementation • Faster, able to handle thousands • Calculated differently producing better looking results (visually pleasing, smoothly avoiding)
The method – Overview • Pedestrian Interactions • => Pedestrian Simulation Model • Collision Avoidance
The method – PedestrianInteractions • Scanning and Externalization • Personal Space • Principle of Least Effort
The method – Pedestrian Sim. Model • Modeled as little cylinders with radius r • The pedestrian tries to reach its goal • The goal is pulling the pedestrian towards itself with a goal force
The method – Pedestrian Sim. Model • The pedestrian wants to move at a certain speed • It reaches this spreed gradually over time
The method – Pedestrian Sim. Model • All the walls act on the pedestrian repulsively • Diw shortest distance between P and wall • Ds safe discance P likes from the wall
The method – Pedestrian Sim. Model • A pedestrian keeps a distance from others to feel comfortable (“Personal space”) • Modeled as a disc with radius p>r (is varied) http://www.mysocalledsensorylife.com/?p=2021
The method – Pedestrian Sim. Model • The collision occurs when another pedestrian Pj comes in the personal space of Pi at time tc
The method – Pedestrian Sim. Model • A pedestrian has an anticipation time (can vary) • Collisions within this time are actively avoided • To simulate this an evasive Force is applied
Collision avoidance • Collision prediction
Collision avoidance • Selecting pedestrians • Sorted on increasing collision time • Keep the first 2 to 5
Collision avoidance • Avoidance maneuvers
Collision avoidance • Computing the evasive Force • Weighted sum of N forces • OR • Iterative approach! Agile101.net
Implementation • Efficient Collision Prediction • Anticipation time • Iterative approach • Vary p, r, v and t • Maximum distance
Implementation • Adding variation • Noise Force • Time integration • Simulation time steps • Sum of forces • Orientation
Experiments – Claim recall • Anticipation/prediction based • Easier in formulation and implementation • Faster, able to handle thousands • Energy-efficient motions • Less curved paths • Smooth natural flow • Oscillation-free • Visually pleasing/natural looking
Movies… • file:///C:/Users/Jessica/Downloads/Circle.avi • file:///C:/Users/Jessica/Downloads/Scene0.avi • file:///C:/Users/Jessica/Downloads/Scene1.avi • file:///C:/Users/Jessica/Downloads/Scene2.avi • file:///C:/Users/Jessica/Downloads/Scene3.avi • file:///C:/Users/Jessica/Downloads/park.avi • file:///C:/Users/Jessica/Downloads/crosswalks.avi
Assessment – promises • Scanning and externalization? • Natural looking? • Easy implementation: extendability?
Assessment – method • Reasoningthatleadsto smart pedestrianselection • Reasoningthatleads to iterativeapproach • Howwouldthismethod combine withobstacleavoidancemethods?
Assessment – experiments • 25% of CPU usage? • What about the high-cluttered environments? • How is the time step chosen?
Assessment – results • Swirl effect • Up front anticipation results in no interaction • No ellipse-shaped personal space needed?
Assessment – shortcomings • No couples or coherent groups • No cultural, cognitive or psychological factors • Nothing like the reciprocal method
Developments since then • Path Planning for Groups Using Column Generation (Marjan van den Akker, Roland Geraerts e.a.) • http://gamma.cs.unc.edu/PLE/pubs/PLE.pdf • http://d.wanfangdata.com.cn/periodical_zggdxxxswz-jsjkx201003011.aspx • http://people.cs.uu.nl/ioannis/publications.html