Efficiently exploring for human robot interaction: partially observable Poisson processes

Abstract

Consider a mobile robot exploring an office building with the aim of observing as much human activity as possible over several days. It must learn where and when people are to be found, count the observed activities, and revisit popular places at the right time. In this paper we present a series of Bayesian estimators for the levels of human activity that improve on simple counting. We then show how these estimators can be used to drive efficient exploration for human activities. The estimators arise from modelling the human activity counts as a partially observable Poisson process (POPP). This paper presents novel extensions to POPP for the following cases: (i) the robot’s sensors are correlated, (ii) the robot’s sensor model, itself built from data, is also unreliable, (iii) both are combined. It also combines the resulting Bayesian estimators with a simple, but effective solution to the exploration-exploitation trade-off faced by the robot in a real deployment. A series of 15 day robot deployments show how our approach boosts the number of human activities observed by 70% relative to a baseline and produces more accurate estimates of the level of human activity in each place and time.