Active Tracking

1
Active Tracking

• Interfacing tracking algorithms withPan Tilt
  Zoom controls
• Doug Gray (dgray_at_soe.ucsc.edu)
• 6/7/2004

2
Introduction

• Why Active Tracking?
• Artificially increase field of view (mosaic)
• Optimize the size and position of a Region of
  Interest
• All tracking algorithms fail when the target
  leaves the image frame

3
Camera Setup

• Sony EVI-D100
• 380,000 Element CCD
• Pan ( 100), Tilt ( 25)
• Zoom (10x Optical, 40x Digital)
• Dazzle AtoD Converter
• NTSC to Firewire
• Sony VISCA cable
• Proprietary Sony design interfaces with an RS232
  port

4
Software, Libraries and Protocols

• Microsoft DirectShow
• Extension of DirectX
• Used by OpenCV for video control
• Takes advantage of Hardware / Operating system
  interface
• Intel OpenCV
• Open source collection of Computer vision and
  Image Processing libraries (BSD style license)
• Our application is an extension of CamShiftDemo
• Sony VISCA Camera Control
• Serial packet oriented communication protocol
• Scalable to multiple cameras (daisy chaining)
• 9600 baud, 8bit, no parity

5
Software Setup
Movement Data
Xiaoqiang
Mean Shift Algorithm
Threshold Algorithm
Tracker Data
Controls
Doug
Video
Pan Tilt Zoom Control Library
GUI Controls
CamShiftDemo
Control Signals
OpenCV
Microsoft DirectShow
COM Port
Microsoft Windows (2000/XP)
Hardware Interface
6
Algorithm

• Pan Tilt Zoom Threshold
• Easily adjusted to different systems
• Fast
• Suppresses smallzero mean motion
• Update Frequency
• Adjustable
• Default 500ms

7
Challenges

• Hardware Interfacing
• Timing and Synchronization issues
• Instability
• Zooming causes tracker corruption
• Solution Zoom very slowly
• Once tracking is corrupted, PTZ controls may
  become erratic
• Solution Tracker confidence level

8
Future Work

• Active Calibration
• Compare optical flow of known camera movement to
  obtain both intrinsic and extrinsic camera
  parameters
• 2D Flashlight
• Create a large dynamic mosaic and use a
  flashlight to update a region of Interest
• Active surveillance system