Bristol Interaction Group


Personalized View-Overlays for Tabletops


Multi-touch tabletops allow people to gather around them to visualize and interact with its contents in an intuitive and effective way. Imagine if, while you and your colleages interact with shared information, the tabletop could contain pieces of information (such as emails, pictures) that are only visible to you. Imagine if these personal contents did not occlude or interfere with what the rest of the group could see. Imagine if these personal contents could contain any type of media, even 3D stereo graphics, without the need of 3D glasses or any other devices. This vision has become possible with PiVOT:  you can access everything you need to work collaboratively whilst still being able to work independently at the same time and on the same tabletop.


Abhijit Karnik, Diego Martinez Plasencia, Walterio Mayol-Cuevas, and Sriram Subramanian. 2012. PiVOT: personalized view-overlays for tabletops. In Proceedings of the 25th annual ACM symposium on User interface software and technology (UIST ’12). ACM, New York, NY, USA, 271-280. DOI=10.1145/2380116.2380151



GizMag : 10th October 2012 “PiVOT tabletop display simultaneously delivers two different ‘view zones'”.

ScienceDaily: 8th October 2012 “Digital Tabletop System With Views On Demand”.

PiVOT was submitted to UIST 2012 and has been accepted for presentation in Boston in October 2012.

It is also one of the entries selected for the Innovation Showcase at Venturefest Bristol (7th November 2012).


The details on how PiVOT works is covered in the next section.

One question we get is where can this be used?

While we do not want to limit the possibilities of usage, we conceived PiVOT with mixed-focus collaborative tasks in mind. Such tasks typically involve smaller personal tasks with access to information that is not necessarily shared. The main task however requires the focus of all individuals of the group.

A good usage scenario would be a planning meeting wherein all individuals concentrate on a single schedule shown on the shared view. Individuals can access their personal calendars or notes in the personal views without losing focus of the planning activity.

Another example is a war-room setup or disaster management. The individuals involved in the shared activity may have access to information meant for them only and at the same time, need to share parts of it to coordinate an activity. In such a setup, PiVOT’s personal overlays help the users to access their information privately and at the same time collaborate with others.

PiVOT could also serve as a teaching aid in digitized classrooms where the teacher can use the personal view for access to notes.

 The other question we get is that hasn’t this been done before?

A simple answer is ‘no!’. There are other approaches that generate two views  (before one of the reader trots out a reference to the Land Rover display) PiVOT is not just about two views. It is about two view-zones. The shared view-zone as we call has content common to all users. However the personal view-zone is the innovative step from us. This zone can contain up to 3 pairs of stereoscopic views which do not interfere with each other. That’s a total of 7 views with the current hardware. And these stereoscopic views don’t require you to wear glasses.

How It Works

PiVOT aims to address the ability of a device to deliver a.) a common view to a group of people and b.) add multiple personalized views for individuals within the group.

This is a technological challenge which we solve with a novel combination of two well known see-through display systems viz. Lumisty and MUSTARD.

The first one, Lumisty film, acts as a direction-dependent diffuser which displays the shared view meant for the group. This shared view is accessible from the side of the table, but is totally transparent from the top.

The second one, MUSTARD, becomes visible as the user leans forward and allows him to see the personalized view. MUSTARD uses a liquid crystal sandwich which allows us to deliver entirely different views to the each user in the personal viewzone. Given the size of the device and other operational parameters, up to 3 users can view personalized content which can be unique to each view. This is the key differentiator for our system.

Another additional advantage of using MUSTARD is that the personalized view can show 2D as well as stereoscopic 3D views without needing glasses. By tracking the user’s position inside the personal viewzone, we can also deliver perspective corrected 3D content irrespective of the user’s position.

The personal viewzone also contains an enhanced view which can be utilized as a source of additional information to the viewers or can serve as a way for the users in the personal viewzone to keep track of the activities happening in the shared view. This can enhance collaborative tasks based around a tabletop.