A novel volumetric display using fog emitter matrix

This paper presents a novel volumetric display based on projection on a non-planer and reconfigurable fog screen. Unlike conventional fog projection systems which produce 2D images on flat screens, our display scatters different parts of the projected image at different depth levels, thus allowing volumetric data to be displayed in the real 3D space. We constructed the fog screen with a 2D array of nozzles that are individually switchable, while the switching pattern is tightly synchronized with the video content. Our system is superior to many existing approaches at many levels. First, our display does not require head tracking, glasses or head-mounted devices while allowing high resolution, full color 3D image to be observed from wide viewing angles by many people at the same time. As compare with various existing approaches, our system is relatively easy to setup and low cost. Most importantly, our immaterial, mid-air display allows users to directly touch and manipulate virtual objects in 3D under marker-free and barrier-free settings which opens up immense tangible and creative interaction possibilities. In this paper, we provide the details of display mechanism and design prototype, as well as a constrained optimization problem to find the projection distance that can maximize the display resolution. A number of real display examples will demonstrate the performance of the proposed system.

I. Introduction

3D displays have a wide range of applications in all disciplines, from art, design and entertainment, to engineering and scientific visualization, medical imaging and tele-presence. Many related technologies have been developed over the past decades and several works have made remarkable achievements. The autostereoscopic display developed in [1] used a rapid-spinning mirror to reflect the light field images from a high-speed projector and render a 360° observable image. Similar mechanism has been employed by [2], [3] and many other swept-volume displays to produce a series of fast-moving slices of the 3D object and base on human's persistence of vision POV to fuse the slices into a single 3D image. The display volume of these systems are usually small and enclosed in a container that is not reachable by users. [4], [5] used laser-plasma scanning to create an array of illumination points in mid-air. The display can only produce sparse (low resolution) and single-color luminous points. Also, the use of high power laser beam would induce safety concerns. Recently, Pixel Dust presented in [6], [7] used acoustic-potential field to trap and levitate small, light-weight objects by standing waves and create patterns for projection. This approach cannot be used for high-resolution volumetric display as only a low-density, 2D layer of particle pattern can be created at a time. inFORM [8] is a 2.5D shape display with motorized pins that combines a Kinect-projector system for tangible interaction.