Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ego-motion Sensor for Unmanned Aerial Vehicles Based on a Single-Board
  Computer   This paper describes the design and implementation of a ground-related
odometry sensor suitable for micro aerial vehicles. The sensor is based on a
ground-facing camera and a single-board Linux-based embedded computer with a
multimedia System on a Chip (SoC). The SoC features a hardware video encoder
which is used to estimate the optical flow online. The optical flow is then
used in combination with a distance sensor to estimate the vehicle's velocity.
The proposed sensor is compared to a similar existing solution and evaluated in
both indoor and outdoor environments.

35
The categories of this paper are: mtrl-th
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The categories of this paper are: solv-int
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The categories of this paper are: nucl-ex
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The categories of this paper are: bayes-an
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The categories of this paper are: cmp-lg
3
The categories of this paper are: physics
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The categories of this paper are: q-fin
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The categories of this paper are: q-bio
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The categories of this paper are: hep-lat
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The categories of this paper are: comp-gas
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The categories of this paper are: nlin
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The categories of this paper are: funct-an
2
The categories of this paper are: math
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The categories of this paper are: chem-ph
13
The categories of this paper are: quant-ph
7
The categories of this paper are: hep-th