This paper discusses on-line recognizing contacts of objects for robotics application, using multiple sensor modalities. Specifically, it shows how to integrate and reason about sensor information obtained by position/orientation and vision sensors in the presence of sensing uncertainties.
Jing Xiao, Jing Xiao,
"Recognition of contacts between objects in the presence of uncertainties", Proc. SPIE 1470, Data Structures and Target Classification, (1 August 1991); doi: 10.1117/12.44861; https://doi.org/10.1117/12.44861