Title: Motion Analysis
1Motion Analysis Human Figure
Processing video to extract information of objects
3 categories of objectives
Motion tracking
Pose reconstruction
Motion and subject recognition.
2Motion Tracking
Identification and location of subject
characteristics
Based on features or regions Optical
flow silhouettes
Applications Pedestrian flow traffic flow.
3Pose Reconstruction
2D or 3D tracking of body parts
- Applications
- Medical - gait analysis
- Sports
- Entertainment
- Usually with geometric model
- DoFs?
- Silhouette
- Color, Textures
- What?
- Entire pose
- Hand arm gestures
- Facial expression lips
With instrumentation MoCap.
4Recognition
Abstract out the what high level semantics
Extract discriminators Neural Nets PCA
Can be based on tracking or pose reconstruction
What? Gestures - by arm motion Person - by
his/her gait American Sign Language (ASL) - by
finger position.
5Problems.
Complex, varying environment
Segmentation issues
Occlusion of body parts.
6Possible simplifying assumptions on environment
Static and/or uniform background
Restriction on movement
Restrict number of objects
Restrict complexity of objects.
7Segmentation problems
Image quality
Motion blur
Low contrast images
Strong shadows, reflections
Loose fitting clothes - use tight fit, markers.
8Occlusion problems
3D model, 2D image
Underconstrained problems
Use multiple cameras.
9Taxonomy
Model based or features Edges Regions colors,
textures
2D v. 3D
Static v. dynamic processing e.g. use nOptical
flow
Single camera v. multi-camera Locate points
uniquely Single underconstrained
10Processing Variations
- Dynamic update of background
- Changing illumination
- Shadows, brightness
- Update of static fixtures
- Background subtraction
- Contract enhancement
- Shadow removal
- Edge detection
- Region filling
- Clustering
- Silhouette formation
- Body part matching
- Find appendages, joints
- Toe - heel curvature
- Head
Speed Real-time only previous frames Interactive
Batch
Need initialization?
Need previous examples?
Single frame or temporal info.
11Cambridge Research lab
12Cambridge Research lab
13Cambridge Research lab
143D Model Optimization
153D Model Optimization
Temporal coherence Anatomy Area matching Boundary
matching
Matching features of synthetic image with live
image
16Gavrila
Multiple cameras Detect edges - remove static ones
17Gavrila
18Gavrila
19MERL
Capture motion snippets Baysian formulation
20Sminchisescu
21Sminchisescu
22Sminchisescu
23Sminchisescu