SpiroSurface: A Repulsive and Attractive Force Display for Interactive Tabletops Using a Pneumatic System.

We present SpiroSurface, a novel force display for interactive tabletops. SpiroSurface uses a pneumatic system to generate both repulsive and attractive forces. We develop a prototype with 5x5 grid holes on the surface connected to an air compressor and vacuum tanks through electromagnetic valves. The display can output a maximum of +1.0 and -0.08 megapascal (MPa) pressure from a hole that generates 74 and -6 N force. We investigated the latency of the output pressure through pneumatics and an experiment, which indicated a minimum of 50-ms latency. The display allows the creation of three kinds of novel interactions: (1) enhancement of GUI, (2) deformation of soft objects, and (3) three-degree-of-freedom rotation of objects. In the first application, users can feel the force from the display without holding or attaching additional devices. In the second and third applications, the shape and motion of an object on the surface can be manipulated without embedding additional active components in the objects. These aspects allow users to easily experience interaction and expand the freedom of interaction design. We introduce several examples combining video projection and motion tracking. These examples demonstrate the potential of the display.

Direct Gaze Estimation Based on Nonlinearity of EOG.

Electrooculography (EOG) is one of the measures used to estimate the direction of a person's gaze; however, conventional EOG techniques suffer from a drift issue which makes it difficult to extract an accurate absolute eye angle. The technique proposed here is based on the nonlinearity of the EOG and offers a practical solution to this problem. It estimates the absolute eye angles before and after a saccade, which cancels the offset due to the drift. Additionally, it does not require any effort from the user or any target, but instead uses only the difference of the EOGs. Experiments with five subjects confirm that the proposed technique can estimate the absolute eye angle with an error of less than 4(°). They also show improvements are achieved with several options such as weighting and multiple saccades. The technique will contribute to practical EOG-based interaction systems.

Automatic drift calibration for EOG-based gaze input interface.

A drift calibration technique for DC-coupled EOG (electrooculogram) systems is proposed. It assumes a non-linear relationship between EOG and eye angle and estimates the absolute eye angle by the EOG differences during saccade. Drift is calibrated every saccade without user's explicit action, so it is especially suitable for long-term gaze input interfaces. An experiment confirms that it can estimate horizontal absolute eye angle with an error of about 5° in addition to accurate eye movement.