sk e y e ball: real-time vision system for an autonomous model airplane danko antolovic

SKEYEBALL: REAL-TIME VISION SYSTEM FOR AN

AUTONOMOUS MODEL AIRPLANE Danko Antolovic

Pervasive Technology Laboratory, Indiana University, Bloomington

Bryce Himebaugh

Steven D. Johnson

Department of Computer Science, Indiana University, Bloomington

Goals and Objectives of Skeyeball:

- Situated vision research:

- situational awareness => vehicle autonomy

- navigation

- target tracking

- collision avoidance (obstacles, terrain, other UAVs)

- Development of tools and methods for reliable embedded design:

- e.g. SPIDER avionics, under development at NASA/LRC

- Development of a platform for undergrad/graduate education

Situated computer vision

Why?

-Vision is an ill-posed problem

-Research has lead to a profusion of algorithms, many ill-suited for control and guidance applications

Situated application places stringent constraints on algorithms and hardware architecture. A situated vision system must be:

-Embedded, i.e. compact and mobile

-Real-time

-Integrated into the control loop(s)

The Vision Funnel

9.3 Mbytes/sec

YES/NO ?(~10 times/sec)

thresholding

edge detection

segmentation(logical analysis)

target identification

Data reduction by a factor of 10,000,000

Start with a gray-scale aerial shot …

… threshold it to B/W

… trace edges

… segment the edge map into connected components

… calculate moments of inertia for each component

Moments are invariant under rotations and translations.

Move the camera to bring the target in the center of the vision field.

15enable sigs.

4

addr

7

4

216

8

8

15

8

XC4010FPGA

back end

sampling clk.

digitized video

sync signals

LM1881

AD876

NTSCXC4010FPGA

front end

CY7C007AVDPRAM(32K)

Servos

Servo duty cycles

B/W threshold

MCF5307

Serial port

IRQ5

diagnosticsParallel port

8

duty cycles

servo motion

addr

data

data

video &threshold

servo data

PIC16F877

Servo position(analog)

4

2

controls

enable sigs.

Unified cache(DRAM only)

DRAM(8M)

Camera

To ground station (RF)

Architecture of the Vision Hardware

Measurement of the tracking speed

Maximum sweeping rate: 45 deg./sec, more than adequate for the airplane’s overflight speeds and a camera field of ca. 50 deg.

High-Priority Objectives …

- stable and unambiguous aerial tracking

- an orbiting mode, in which the aircraft autonomously circles above (or follows) an acquired target

- collision avoidance capability for stationary obstacles, to be extended in the future to avoidance of other UAVs