Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Monocular Direct Sparse Localization in a Prior 3D Surfel Map   In this paper, we introduce an approach to tracking the pose of a monocular
camera in a prior surfel map. By rendering vertex and normal maps from the
prior surfel map, the global planar information for the sparse tracked points
in the image frame is obtained. The tracked points with and without the global
planar information involve both global and local constraints of frames to the
system. Our approach formulates all constraints in the form of direct
photometric errors within a local window of the frames. The final optimization
utilizes these constraints to provide the accurate estimation of global 6-DoF
camera poses with the absolute scale. The extensive simulation and real-world
experiments demonstrate that our monocular method can provide accurate camera
localization results under various conditions.

29
The categories of this paper are: funct-an
19
The categories of this paper are: eess
23
The categories of this paper are: solv-int
9
The categories of this paper are: nlin
8
The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
2
The categories of this paper are: math
37
The categories of this paper are: supr-con
11
The categories of this paper are: hep-lat
24
The categories of this paper are: dg-ga
27
The categories of this paper are: comp-gas
34
The categories of this paper are: chem-ph
3
The categories of this paper are: physics
13
The categories of this paper are: quant-ph
26
The categories of this paper are: bayes-an