Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Detecting and avoiding frontal obstacles from monocular camera for micro
  unmanned aerial vehicles   In literature, several approaches are trying to make the UAVs fly
autonomously i.e., by extracting perspective cues such as straight lines.
However, it is only available in well-defined human made environments, in
addition to many other cues which require enough texture information. Our main
target is to detect and avoid frontal obstacles from a monocular camera using a
quad rotor Ar.Drone 2 by exploiting optical flow as a motion parallax, the
drone is permitted to fly at a speed of 1 m/s and an altitude ranging from 1 to
4 meters above the ground level. In general, detecting and avoiding frontal
obstacle is a quite challenging problem because optical flow has some
limitation which should be taken into account i.e. lighting conditions and
aperture problem.

25
The categories of this paper are: patt-sol
28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th
17
The categories of this paper are: q-fin
20
The categories of this paper are: acc-phys
26
The categories of this paper are: bayes-an
6
The categories of this paper are: astro-ph
30
The categories of this paper are: q-alg
32
The categories of this paper are: atom-ph
27
The categories of this paper are: comp-gas
3
The categories of this paper are: physics
21
The categories of this paper are: adap-org
2
The categories of this paper are: math
13
The categories of this paper are: quant-ph
0
The categories of this paper are: hep-ph
33
The categories of this paper are: plasm-ph