HARP: A framework for visuo-haptic augmented reality

Visuo-Haptic Augmented Reality (VHAR) is a technology, which enables users to see and touch virtual objects. It poses unique problems to developers, including the need for precise augmentations, accurate colocation of haptic devices, and efficient processing of multiple, realtime sensor inputs to achieve low latency. We have designed and implemented the software framework HARP, which addresses these issues and simplifies the creation of haptic-enabled Augmented Reality (AR) applications. It allows developers to compose their applications on a high level of abstraction and hides most of the complexity of VHAR. Our contribution is the initial design and implementation of the framework, which we have validated in nine VHAR research projects ranging from simple interaction design to psychophysical experiments. We discuss limitations of our approach and future developments. These insights will be helpful to researchers and framework designers in the field of VHAR.