Active Vision System for Unusual Motion

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Active Vision System for Unusual Motion

• By Jing Zhong
• CS580 Image and Video Computation
• Spring 2002

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Overview

• Active Vision
• An active vision system is one that is able to
  interact with its environment by altering its
  viewpoint rather than passively observing it, and
  by operating on sequences of images rather than
  on a single frame.
• Three Types of Temporal Events
• Temporal Textures, Activities, and Motion Events

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Outline

• Goal
• In this project, we will use a monocular camera
  system to detect and track the area of unusual
  motion in the Field of View.
• Background
• The idea is inspired by the attentive mechanism
  of human vision. Previous work use camera control
  to realize active vision. However, they did not
  study the detection of unusual motion and
  extraction of the objects exhibiting unusual
  motion

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Active Vision System

• Attention
• The attention mechanism in this project is driven
  by the unusual motion detection. We will build
  a simple statistical model for the unusual
  motion.
• Fixation
• Control the camera systems so that the
  attention is located at the center of the
  camera image plane and keeps the size proportion
  of interested object in the image invariably.
• Pursuit
• Keeping the fixation point as close as possible
  to the attention during the object or camera
  movement.

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Current Work
y

• Motion Flow Field Computation
• Based on Intel OpenCV Library
• Flow Field Decomposition
• Decompose a bunch of frames into small
  rectangular sub-regions. After adding the time
  axis (30 frames), we get a cube for each
  sub-region.
• Feature Extraction
• Direction and Magnitude of Optical Flow
• Generate empirical distribution in each cube
  (histogram)
• Distance Computation

x
t
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Video 1 and Motion Flow Field Map
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Histogram(usual motion)
Histogram(unusual motion)
Unusual Motion Cube
Distance
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The Histogram Distribution
185 Bin, 37 for the direction of the optical
flow, 5 for magnitude of the optical flow.
Usual Motion
Unusual Motion
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Video 1 and Motion Flow Field Map
Failed
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Unusual Motion Cube
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Future Work

• Using better distance measures
• Using more robust of algorithm to build motion
  model
• Combine tracking algorithm to track the unusual
  object
• Dynamic camera control, so that we can zoom in
  and track the unusual motion