egr494: senior project in computer engineering
DESCRIPTION
EGR494: Senior Project in Computer Engineering. James Painter. Primary Goals. Fully develop vision system for Wunderbot IV autonomous robot Adapt it specifically for June 2008 Intelligent Ground Vehicle Competition (IGVC). Secondary Goals. - PowerPoint PPT PresentationTRANSCRIPT
Primary Goals• Fully develop vision system for
Wunderbot IV autonomous robot• Adapt it specifically for June 2008
Intelligent Ground Vehicle Competition (IGVC)
Secondary Goals• Code a closed-loop motor control
system for accurate robot motion response
• Writing/debugging of LabVIEW code for synchronization of all hardware subsystems
Vision System – Prior Work• Acquisition of DVT Legend 554C XE
high-resolution video camera• Coding of LabVIEW sub-VI to acquire
camera’s TCP/IP communication string
Vision System - Tasks1) Build camera mount at optimal location
and angle2) Image processing to parse white lines in
robot’s vision3) Manage line data in LabVIEW and
integrate with adaptable motion-control algorithms to steer robot on correct path
4) Properly format the gathered vision data to interface with path-planning code – will be used to map traversed course
Status - Fall 2007• Primitive path detection algorithm
calculated gradient• Found high contrast in two small,
filtered regions to simulate stereo vision
1. Camera Mount• Built as part of new utility pole, sits
back 16” from rear bumper and 4’ up• Secured with adjustable wing nuts on
angle brackets
Viewable Region
Processing Time Reduction• Increase of viewable region allows
cropping of imageTop Edge Cropped
Processing Time Speedup
15% (153 lines) 16% (90ms)
24% (246 lines) 25% (140ms)
2. Image Processinga) 3x3 dilate filterb) Hough Transform for line detectionc) Line thickness sensor
i. 75% intensity contrastii. Accepts first 3 chains of 50 pixels
(possibly 3 best, but much slower)
Image Processing SamplesUnfiltered Filtered
arbitrary results
more accurate
Image Processing SamplesUnfiltered Filtered
useless data accurate
Preliminary Results
Filtering Shadowsa) Maximum separation of 300 pixels
(window width of 1079)b) “Straightness” of less than 75-pixel
deviation from averaged center line
accepted
filtered
3. Motor Control• Line position data sent to on-board
PC via TCP/IP• LabVIEW code plots the line on a
local (soon global) map
• Line depth and lateral position determine how sharply to turn and whether to back up
Far
Near(sharper turn)
Immediate Obstacle(sharper
turn)
Outlying Obstacle
Outlying Obstacle
• Designed controls for adjusting numerous parameters - allow dynamic motor control adaptation for different environments− Overall target speed− Backup speed− Proximity for backing up− Turning aggressiveness (factoring depth
and lateral position separately)− Minimum line width
• Control panel
Video Clip (2x speed, 23 sec.)
Upcoming Tasks• Introduce line averaging, where
points outside a given standard deviation are discarded
• Increase rate of TCP/IP data transfers• Integrate all subsystems and plot
global, dynamic map of lines and obstacles
References• R. Bishop. LabVIEW 8 Student Edition, Book & CD-ROM Edition,
Upper Saddle River, NJ: Prentice Hall, 2006.• Installation and User Guide for DVT Vision Sensors, Cognex
Corporation, May 2006.• DVT Script Reference Manual, Cognex Corporation, August
2003.• Dougherty, Edward R. Electronic imaging technology,
Bellingham, WA: SPIE Optical Engineering Press, 1999.• A.L. Kesidis and N. Papamarkos. “A Window-Based Inverse
Hough Transform.” Pattern Recognition 33 (2000): 1105-1117.