Augmented Reality System Calibration for Assembly Support With the Microsoft HoloLens

The Microsoft HoloLens is the latest augmented reality (AR) capable head-mounted-display (HMD) with the potential to leverage AR applications in manufacturing and design. Its optical system and the embedded tracking capability are superior to many precursor HMDs and mitigate several known obstacles such as size, massive weight, visual quality, and tracking latency. Especially the last one, the not-noticeable tracking latency, is a convincing factor for people outside an AR community. Along with its onboard tracking, it allows the HoloLens to populate the physical world with virtual objects and to maintain their position while the user is moving. Although these capabilities are already convincing, the majority of applications in assembly and design require a precise alignment of virtual objects with physical parts. Especially, if a user moves the majority of components in an application situation, thus, virtual information need to move along with the physical part to convey them semantically correct. Object tracking and automatic registration are required to establish this functionality. This paper introduces an AR system which integrates an external range camera-based tracking system and the HoloLens. It incorporates two calibration procedures, which are required to register virtual 3D objects with physical components. This AR system can be used for different visualization tasks along the product life-cycle, spanning the range from training to decision making, although our major area is currently manual assembly.