



3D images created with a pearl and ultrasound

Diagram describing the projection device used, as well as some forms created by the device. Credits: Ryuji Hirayama et al. 2019

A step towards next-generation visual entertainment

Sound and tactile images

Technology can create a variety of colorful 3D shapes, accompanied by sounds and a tactile response. Credits: Ryuji Hirayama et al. 2019

Towards advanced holographic technology for everyone

Bibliography:



Article: A volumetric display for visual, tactile and audio presentation using acoustic trapping



Authors: Ryuji Hirayama, Diego Martinez Plasencia ', Nobuyuki Masuda' & Sriram Subramanian



DOI: https://doi.org/1o1038/s41586-019-1739-5



Source

The dream of science fiction writers, holograms are now an active field of research, and more and more advanced prototypes have emerged in recent years. If the technology is not yet to match the holographic projectors of the Star Wars franchise, engineers are continually surpassing new limits. This is the case of a recently developed pseudo-holographic technology, based on an ultrasound system, for projecting shapes and touching them.Researchers in Sussex have developed a device that projects animated objects in 3D that can interact with viewers. A demonstration showed a butterfly flapping its wings, a countdown detailed by numbers hanging in the air and a planet Earth in rotation and multicolored. Beyond digital signs and interactive animations, scientists want to use it to visualize and better perceive data.Although the images are similar, the camera is not the kind of holographic projector for Star Wars movies. Instead, he uses a 3D field of ultrasonic waves to levitate a polystyrene bead and model it at high speed to draw shapes in the air. The study was published in the journal Nature .The 2 mm wide bead moves so fast, at speeds approaching 20 km / h, that it traces the shape of an object in less than a tenth of a second. At such a speed, the brain does not see the pearl in motion, only the complete form it creates. The colors are added by integrated LEDs on the screen, which illuminate the pearl as it moves.Because images are created in a 3D space, they can be viewed from any angle. And by carefully controlling the ultrasonic field, scientists can make objects talk or add sound effects and musical accompaniments to moving images. Further manipulation of the sound field allows users to interact with objects and even feel them in their hands.Sriram Subramanian, team director, explains that besides digital signage, the display could also be used for new forms of visual entertainment. " Let's say you want to create a Harry Potter experience. You can reach out to cast a spell and, as you move it, you can see and feel a glowing ball grow in your palm, and we could also have a sound coming out of it . "Ryuji Hirayama, who participated in the construction of the screen, says that making such a device was a long-time dream. But he considers that "the display of multimodal acoustic traps" is a step towards more sophisticated systems. " I think that in the future, such screens will allow us to interact with our family and friends as if they were nearby, so we can see them, touch them and hear them ."The images are created between two horizontal plates dotted with small ultrasonic transducers. These create an inaudible 3D sound field containing a tiny pocket of low pressure air that traps the polystyrene bead.Move the pouch slightly changing the output of the transducers and the pearl moves with it. The most basic version of the display creates 3D color animations, but the authors describe how they improved the display to produce sounds and tactile responses.Speech and other sounds, such as musical accompaniment, were added by vibrating the polystyrene bead when it was around it. Vibrations can be tuned to produce sound waves across the entire range of human hearing, creating, for example, clear, clear speech. Another trick is making touch display by manipulating the ultrasound field to create a virtual "button" in suspension.The prototype uses a single bead and can create images in an air cube 10 cm wide. But future displays could use more powerful transducers to create larger animations and use multiple beads at once.Subramanian stated that existing computer software could be used to prevent small pearls from colliding with each other, although the choreography of lighting several beads in the air is another problem. If technology can be improved, it could transform 3D printing by building objects from tiny droplets of different levitating materials." What's interesting about the tactile content is that it was created using ultrasonic waves. Unlike the simple vibrations that most people experience via smartphones or game consoles, ultrasound moves through the air to create precise patterns against the hands. This allows for multimedia experiences where the objects you feel are as rich and vibrant as the ones you see on the screen, "says Euan Freeman of the University of Glasgow.Julie Williamson, also from Glasgow, says that levitating screens are a first step towards truly interactive 3D displays. " I imagine a future where 3D displays can create experiences that are indistinguishable from the physical objects they simulate ."This video summarizes the work of researchers and shows technology in action: