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Near Touch Illumination (NTI)

This hardware configuration is used to create near touch interactive systems that track users hands as well as features of each hand which usually represents the fingertips. Ultimately, the system can detect touch and hover event and report distance of each fingertip. Furthermore, by analysing movement of features we can detect what type of motion user is performing with their hands.


The idea that users should be able to interact with digital content on a surface by using their hand motion near the surface has been around for many years. Marquardt et. al.[1] argued that the interactive surface and the space immediately above it should be seen as a continuum, and that gestures on the surfaces should flow seamlessly into gestures above the surface. They use a marker based Vikon system to perform the tracking. Several other hardware systems have been proposed to enable interaction near the surface. Takeoka et al.[2] introduced a very accurate technique for detecting hand posture near the surface, using multiple planes of infra-red light stacked above the surface and a camera mounted behind the screen. What is common in all of these method is that they are relatively complex, expensive and difficult to build.

The near touch illumination technique, designed and implemented by Balali et.al.[3] is a low cost and easy to construct solution for hobbyist and researchers who want to taste and evaluate interactions in the near touch area.


Detecting near touch actions enables several new ways of interacting with digital content. For example, it allows a form of interaction similar to a ”mouse-over” event, which can be used to invoke a tool-tip or hover query. However, that is just the tip of iceberg; when you think more about hand motions that are meaningful to users, many new interaction design ideas start to flow. You are encouraged to share and discuss your near touch interaction ideas in the relevant threads on the forum.

How to Build

Building your near touch enabled device is just as easy as DI or DSI, in fact it might be even easier. The objective of this type of hardware is to get a consistent image of the whole hand through the diffuser. To achieve this image, a serries or infrared lights are placed on the edges of the screen.

Figure 1: Drawing of near touch hardware setup.

Figure 2: An example of the source image in NTI captured from the row input of the camera.

List of Parts

Near Touch Tracking Software


NUI Forum Discussion about Near Touch

Aras' Blog

BiDi Screen


1. N. Marquardt, R. Jota, S. Greenberg, and Jorge. The Continuous Interaction Space: Integrating Gestures Above a Surface with Direct Touch. Technical Report 2009-92504, University of Calgary, April 2009.

2. Y. Takeoka, T. Miyaki, and J. Rekimoto. Z-touch: An Infrastructure for 3D gesture interactions in the proximity of tabletop surfaces. In Proc. Interactive Tabletops and Surfaces 2010, November 2010.

3. Aras Balali Moghaddam, Jeremy Svendsen, Melanie Tory, and Alexandra Branzan Albu, “Integrating Touch and Near Touch Interactions for Information Visualizations”, Works-in-Progress at ACM Conf. on Human Factors in Computing Systems (CHI’11), 6 pages, in print, May 2011.