  This paper is a survey work for a bigger project for designing a Visual SLAM
robot to generate 3D dense map of an unknown unstructured environment. A lot of
factors have to be considered while designing a SLAM robot. Sensing method of
the SLAM robot should be determined by considering the kind of environment to
be modeled. Similarly the type of environment determines the suitable feature
extraction method. This paper goes through the sensing methods used in some
recently published papers. The main objective of this survey is to conduct a
comparative study among the current sensing methods and feature extraction
algorithms and to extract out the best for our work.
