# Sensor-based Random Tree (SRT)

The SRT method is a randomized strategy for exploring unknown environments using mobile robots equipped with range finders. In this method a data structure is created which represents a roadmap of the explored area with an associated Safe Region (SR). Each node of the SRT consists of a free configuration with the associated Local Safe Region (LSR) as reconstructed by the perception system the SR is the union of all the LSRs. The LSR is an estimate of the free space surrounding the robot at a given configuration.

Based on the shape of LSR, we have two types of SRT
1. SRT-ball
2. SRT-star


This method also requires localization to know the robot configuration at all times.

> In its basic formulation, the SRT method assumes that the robot always knows its configuration through some localization module. To remove this limitation, we have developed an SRT-based integrated exploration strategy., i.e., a simultaneous localization/mapping/exploration scheme where exploration decisions are taken based on localization potential as well as information gain. In particular, the algorithm relies on an LSR feature-based continuous localization scheme.

### Resources

http://www.diag.uniroma1.it//~labrob/research/SRT.html

http://www.diag.uniroma1.it//~labrob/pub/slides/SRT-Slides.pdf

https://www.youtube.com/watch?v=QLXIdE-k0do

https://github.com/knaidoo29/mistree