@article{10.1145/3453157, author = {Itoh, Yuta and Langlotz, Tobias and Sutton, Jonathan and Plopski, Alexander}, title = {Towards Indistinguishable Augmented Reality: A Survey on Optical See-through Head-Mounted Displays}, year = {2021}, issue_date = {July 2021}, publisher = {Association for Computing Machinery}, address = {New York, NY, USA}, volume = {54}, number = {6}, issn = {0360-0300}, url = {https://doi.org/10.1145/3453157}, doi = {10.1145/3453157}, abstract = {Adding virtual information that is indistinguishable from reality has been a long-awaited goal in Augmented Reality (AR). While already demonstrated in the 1960s, only recently have Optical See-Through Head-Mounted Displays (OST-HMDs) seen a reemergence, partially thanks to large investments from industry, and are now considered to be the ultimate hardware for augmenting our visual perception. In this article, we provide a thorough review of state-of-the-art OST-HMD-related techniques that are relevant to realize the aim of an AR interface almost indistinguishable from reality. In this work, we have an initial look at human perception to define requirements and goals for implementing such an interface. We follow up by identifying three key challenges for building an OST-HMD-based AR interface that is indistinguishable from reality: spatial realism, temporal realism, and visual realism. We discuss existing works that aim to overcome these challenges while also reflecting against the goal set by human perception. Finally, we give an outlook into promising research directions and expectations for the years to come.}, journal = {ACM Comput. Surv.}, month = jul, articleno = {120}, numpages = {36}, keywords = {visual coherence, mixed reality, optical see through, review, Augmented reality, near eye display, head-mounted display, wearable computing} }