Advanced sensing

Question 1

How does global localisation via recognition work?

Answer 1

• make measurements at chosen locations
• recognise learnt locations after training

Question 2

What is a depth measurement histogram?

Answer 2

• look at frequency of depth measurements and build frequency histogram

Question 3

What is probabilistic occupancy grid mapping?

Answer 3

infer which parts of map are free space and which have obstacles

Question 4

How does occupancy grid mapping work?

Answer 4

1. for each cell store and update prob of occupancy
2. initialise unexplored space to constant value

Question 5

Occupancy grid mapping for sonar sensor

Answer 5

1. sonar reports depth z=d
2. cells around distance d from robot likely to be occupied
3. cells depth < d likely to be free
4. for each cell test if lies in sonar beam, given robot position