Crosstalk and brightness in projection-based multiview systems

Immersive visualization environments have generally been built on single user stereoscopic displays. We have extended these systems to multi-view systems that provide perspectively correct stereoscopic image pairs for up to six users. As a result, groups of users can explore a shared 3D virtual environment from all perspectives and discuss it using barehanded gestures. From all displayed images, each user should perceive only one dedicated image per eye. All additional views must be filtered. Consequently, the noise level for each user increases with the number of displayed views. Keeping the image crosstalk under the threshold of human perception is a necessity for this type of visualization system. To separate the images we have used a hybrid approach which combines active shuttering and passive polarization filtering. In projection-based view systems brightness and crosstalk are one of the major issues which have to be handled as the noise increases and the signal brightness decreases with the increase of views. To evaluate different technical approaches for optimization and also to compare these systems with existing single user 3D systems, we have extended the crosstalk measurement approach by Weissman and Woods to our projection-based specific multi-view case where the eye separation is carried out with polarization filters and the user separation with time sequential shutter elements. Our contribution is a method for defining and measuring crosstalk for projection-based multi-view systems.