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Pázmány Péter Catholic University
Faculty of Information Technology and Bionics
See-and-Avoid System for UAV
with Five Miniature Cameras
Tamás Zsedrovits†, Ákos Zarándy*†, Zoltán Nagy*†, Bálint Vanek*, András Kiss*†, Máté Németh*†
†Pázmány Péter Catholic University, Faculty of Information Technology and Bionics, Budapest, Hungary,
*Computer and Automation Research Institute of the Hungarian Academy of Sciences (MTA SZTAKI)
Budapest, Hungary
EESTEC HIT 01/29/2014
Outline
• Goals
• System requirements
• Vision system architecture
• Many core processor array implementation
• Algorithms
Goals
• Unmanned Aerial Vehicle (UAV) technology is maturing
Making
way
for
• UAVs are ready for autonomous missions technically
unmanned aircraft
• Surveillance tasks
The FAA’s effort to bring
• Autonomous missions are not authorized
unmanned planes into the
nation’s airspace faces tough
aspiloted
well as
Automatic collision avoidance device isobstacles,
needed evenpolitical
for remotely
UAVs*
technical.
Work is under way to resolve
questions about privacy and to
find affordable detect-andavoid technologies.
• Missing redundancy
• Missing collision avoidance device
•
Collision avoidance devices
• Radar based
• Applied on large airliners (Airbus)
• Radar and vision
• Applied on large remotely piloted UAVs (predator)
• Transponder based
• TCAS, ADS-B (all manned aircrafts and larger UAVs)
• Vision only
• Currently developed (small UAVs)
• Basic requirements
• Equivalent safety
• Probabilities of collision < 10-11 per flight hour
• Layered approach
Requirements
• Detect a 10m aircraft from 2km
• 0.1 degree/pixel resolution
• min. 220x60⁰ view angle
• Flyable size/weight/power figures
• On-board data storage
collision volume
separation minima
intruder
collision avoidance
threshold
traffic avoidance
threshold
our
track
Framework
Planned on-board sensor and control loop
Architecture
• High resolution camera system in the visual range
• Elongated, (220x60⁰)
• Large view angle
• min 2Mpixel
• FPGA processing system
• High computational power
• Low power consumption
220⁰
Camera
system
FPGA
board
Solid
State
Drive
• Solid state disk
• Bandwidth
• Capacity
• Vibration
to/from onboard control
Camera selection
• Single camera with wide angle optics
• Easy from architectural, algorithmic, and processing side
• Low distortion, ultra wide view angle optics are bulky
• 3 pieces of C-mount cameras
• Good image quality
• Relatively large size, volume, and power (1kg, 10W)
• High speed serial I/O (USB, Gige, fire-wire) difficult to connect to embedded systems
• 5 pieces of miniature cameras (M12 lens)
• Max 1.2 megapixel with global shutter
• 50g, 200mW
• Poorer image quality
• Micro cameras
• Very advantages size/weight/power figures
• Rolling shutter only
Sensor and computational system
• 5 pieces of wVGA micro cameras
•
•
•
•
•
•
Aptina MBSV034 sensor
5g
<150mW
3.8mm megapixel objectives (M-12)
70 degrees between two cameras
Total view angle: 220˚x78˚
• FPGA board with Spartan 6 FPGA
• Solid State Drive (128Gbyte)
752x480
cameras
FPGA
board
Solid
State
Drive
to/from navigation
computer
Mechanics
• Stable camera holder
•
•
•
•
•
•
Alignment
Avoids cross vibration of the cameras
100g
Aluminum alloy
Electronics in the middle
Covered with aluminum plates
Hardware system
• Sensing and processing system
•
•
•
•
•
•
•
•
Field of view: 220°x78°
Resolution: ~2250x752
Frame-rate: 56 FPS
Processor: Spartan6 L45 FPGA
Storage: 128Gbyte (23 min)
Size: 125x145x45mm (5”x6”x1,8”)
Weight: ~450g (1lb)
Power consumption: <8W
Vision system mounted to the airplane
View angle
Panoramic view (stitched images)
Perspective view
Many-core processor arrays implemented in FPGA
• FPGA chips have the largest computational capability nowadays
• In affordable medium sized FPGAs:
• Over 200 DSP cores
• 200 memory blocks
• 500 IO pins
• Low power consumption
• Special purpose processor arrays
• How to utilize this performance?
• Many-core architectures
• Specially optimized data and control paths
• Distributed control units
Image processing system
• Input:
• DVI/HDMI
• [email protected]
• Native camera interface
• Three image processing
accelerators
• Parallel operation
• Optimized for the image processing
algorithm
Image capture
Full frame
preprocessing
Gray scale
processor
Binary
processor
Microblaze
processor
Memory
controller
DRAM
Algorithmic components
• Aircraft detection against sky background
• Preprocessing on the full frame
• Identifying candidate points
• Post processing
• Discarding non-relevant candidate points
• Tracking
• Multi-level global and local adaptivity
• Aircraft detection against terrain background
• Visual-inertial data fusion
• Motion based moving object detection
Preprocessing (full frame)
• Identifies the candidate aerial
objects
• Finds numerous false targets
also
• Local adaptation based on
edge density
• Global adaptation based on
number of candidate points
contrast
calculation
locally adaptive
contrast thresholding
candidate points
Too many or
too few
points?
n
regions of
interest (ROIs)
threshold
adjustment
y
Preprocessing (full frame)
• Identifies the candidate aerial
objects
• Finds numerous false targets
also
• Local adaptation based on
edge density
• Global adaptation based on
number of candidate points
contrast
calculation
locally adaptive
contrast thresholding
candidate points
Too many or
too few
points?
n
regions of
interest (ROIs)
threshold
adjustment
y
Post processing (ROIs)
• Discard edges of clouds
• Significantly reduces the
number of candidate points
• Resulting few targets can be
tracked
cutting the perimeter
of each object
histogram calculation
Variance high?
y
n
accept candidate
point
reject candidate
point
Post processing (ROIs)
• Discard edges of clouds
• Significantly reduces the
number of candidate points
• Resulting few targets can be
tracked
cutting the perimeter
of each object
histogram calculation
Variance high?
y
n
accept candidate
point
reject candidate
point
Post processing (ROIs)
• Discard edges of clouds
• Significantly reduces the
number of candidate points
• Resulting few targets can be
tracked
cutting the perimeter
of each object
histogram calculation
Variance high?
y
n
accept candidate
point
reject candidate
point
Post processing (ROIs)
• Discard edges of clouds
• Significantly reduces the
number of candidate points
• Resulting few targets can be
tracked
cutting the perimeter
of each object
histogram calculation
Variance high?
y
n
accept candidate
point
reject candidate
point
Example 1: Ground camera in hand
Pre- and post processing
Red points: all candidate objects
Green point: allowed by post processing
Pre- and post processing + tracking
Red points: all candidate objects
Green points: allowed by post processing
Blue points: tracked objects
Example : Airborne camera
Navigation aid
• UAV was equipped with INS and cameras
• Attitude was calculated from the INS data
(blue)
• Attitude was calculated from 5 point (red)
and 8 point (magenta) algorithms
• Visual-navigation data fusion development
is going on
Absolute  pitch angles
Absolute  roll angles
80
150
50
60
100
40
40
50
30
20
0
20
0
-50
 [deg]
60
 [deg]
 [deg]
Absolute  yaw angles
200
10
-20
-100
0
-40
-150
-10
-60
-20
-80
-200
615
620
625
Time [s]
630
635
-30
615
620
625
Time [s]
630
635
-100
615
620
625
Time [s]
630
635
Conclusion
• Vision system is under development
• Currently
•
•
•
•
We are replacing the FPGA board
Finalizing the implementation of the image processing subsystem
Fusion of visual and navigation algorithms
Replacing the wVGA cameras with 1.2 megapixel ones
• Expecting the system completion by the end of the year
Thank you for your attention!
• The ONR Grant (Number: N62909-10-1-7081) is greatly acknowledged.
• The support of the grants TÁMOP-4.2.1.B-11/2/KMR-2011-0002 and TÁMOP-4.2.2/B-10/12010-0014 is gratefully acknowledged.
• The financial support provided jointly by the Hungarian State, the European Union and the
European Social Fund through the grant TÁMOP 4.2.4.A/1-11-1-2012-0001 is gratefully
acknowledged.
FPGA, many-core processing and UAV group
Ákos Zarándy
Péter Szolgay
András Radványi
Zoltán Nagy
András Kiss
Pencz Borbála
Németh Máté

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