Improved interaction methods for medical visualization with floating images

Earlier we have reported on developing new medical visualization technology with floating images using the new optical device `DCRA'. Experience with prototype systems has demonstrated the feasibility of easy visualization of complex spatially distributed data, such as MRI or CT data sets; but also indicated the need for better interaction methods. Here we introduce new developments in interaction with floating image visualization systems. A new method improves the sensing of hand position and gestures for the flexible manipulation of the floating images without holding any devices. Another method uses a simple but robust method to sense directly the users' finger when touching the floating image, to give a natural interactive experience. Still another new method uses the `Phantom' haptic device to give the user a tactile feedback on the position of the floating image in the air, as a help for the accurate positioning of markers. We describe the structure and operation of our interactive methods, and discuss the possibilities of their practical application.