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Aerial Vision-Based Navigation and Monitoring in Special Conditions

Amiri Atashgah, Mohammad Ali | 2011

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 41984 (45)
  4. University: Sharif University of Technology
  5. Department: Aerospace Engineering
  6. Advisor(s): Malaek, Mohammad Bagher
  7. Abstract:
  8. This research is dedicated to specific issues in the field of Aerial Vision Based Navigation (VBN). It focuses mainly on vehicles with no pilot such as RPVs and small aircraft; having in mind their safety which must be close to commercial applications. Various methods have been studied and the simplest one; which is based on observation, identification and utilization of landmarks is selected for detailed implementation. In this work, we concentrate on using a single-camera while flying in an unknown environment (MonoSLAM). Other available sensors are accelerometer and GPS receiver to keep the cost down. Different studies show that using a low-cost single camera system is much more efficient as oppose to that with stereo cameras or laser sensors. We effectively employ the so called “Inverse Depth Parameterization” method to resolve estimating landmarks’ distance from the mounted camera. The effects of vehicle dynamics on the images taken by the mounted camera are studied in detail. The results show that blur value exponentially increases by lowering the flight altitude; while it varies linearly with speeds. Moreover, any aircraft angular velocities result in peculiar non-linear effects. In this work, we have effectively simulated different types of environment to test the efficiency of the so-called VBN for Small Air Transportation System (SATS) aircraft. We have also developed tools to vary visibility from camera-standpoint in diverse environments such as mountains, desert and suburban areas. It is also shown that mixed forest and farmland achieves the best performance for SATS aircraft. Different simulations also show that a MonoSLAM Based Navigation System has the ability to provide the level of safety desired for SATS applications; nonetheless, flight tests are still needed to confirm the potentials of the developed environment
  9. Keywords:
  10. Flight Simulation ; Virtual Reality (VR)Environment ; Computer Graphics ; Vision Based Navigation ; Motion Blur ; Waypoint Navigation System

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