Three-dimensional moving holograms breakthrough

A team led by University of Arizona (UA) optical sciences professor Nasser Peyghambarian has developed a new type of “holographic telepresence” that allows remote projection of a three-dimensional, moving image without the need for special eyewear such as 3D glasses or other auxiliary devices.

The technology is likely to take applications ranging from telemedicine, advertising, updatable 3D maps and entertainment to a new level.

The journal Nature chose the technology to feature on the cover of its Nov. 4 issue.

“Holographic telepresence means we can record a three-dimensional image in one location and show it in another location, in real-time, anywhere in the world,” said Peyghambarian, who led the research effort.
“Holographic stereography has been capable of providing excellent resolution and depth reproduction on large-scale 3D static images,” the authors wrote, “but has been missing dynamic updating capability until now.”
“At the heart of the system is a screen made from a novel photorefractive material, capable of refreshing holograms every two seconds, making it the first to achieve a speed that can be described as quasi-real-time,” said Pierre-Alexandre Blanche, an assistant research professor in the UA College of Optical Sciences and lead author of the Nature paper.

The prototype device uses a 10-inch screen, but Peyghambarian’s group is already successfully testing a much larger version with a 17-inch screen. The image is recorded using an array of regular cameras, each of which views the object from a different perspective. The more cameras that are used, the more refined the final holographic presentation will appear.

That information is then encoded onto a fast-pulsed laser beam, which interferes with another beam that serves as a reference. The resulting interference pattern is written into the photorefractive polymer, creating and storing the image. Each laser pulse records an individual “hogel” in the polymer. A hogel (holographic pixel) is the three-dimensional version of a pixel, the basic units that make up the picture.

The hologram fades away by natural dark decay after a couple of minutes or seconds depending on experimental parameters. Or it can be erased by recording a new 3D image, creating a new diffraction structure and deleting the old pattern.

Peyghambarian explained: “Let’s say I want to give a presentation in New York. All I need is an array of cameras here in my Tucson office and a fast Internet connection. At the other end, in New York, there would be the 3D display using our laser system. Everything is fully automated and controlled by computer. As the image signals are transmitted, the lasers inscribe them into the screen and render them into a three-dimensional projection of me speaking.”

The overall recording setup is insensitive to vibration because of the short pulse duration and therefore suited for industrial environment applications without any special need for vibration, noise or temperature control.

One of the system’s major hallmarks never achieved before is what Peyghambarian’s group calls full parallax: “As you move your head left and right or up and down, you see different perspectives. This makes for a very life-like image. Humans are used to seeing things in 3D.”

The work is a result of a collaboration between the UA and Nitto Denko Technical, or NDT, a company in Oceanside, Calif. NDT provided the polymer sample and media preparation. “We have made major advances in photorefractive polymer film fabrication that allow for the very interesting 3D images obtained in our Nature article,” said Michiharu Yamamoto, vice president at NDT and co-author of the paper.

Potential applications of holographic telepresence include advertising, updatable 3D maps and entertainment. Telemedicine is another potential application: “Surgeons at different locations around the world can observe in 3D, in real time, and participate in the surgical procedure,” the authors wrote.

The system is a major advance over computer-generated holograms, which place high demands on computing power and take too long to be generated to be practical for any real-time applications.

Currently, the telepresence system can present in one color only, but Peyghambarian and his team have already demonstrated multi-color 3D display devices capable of writing images at a faster refresh rate, approaching the smooth transitions of images on a TV screen. These devices could be incorporated into a telepresence setup in the near future.

Source: http://www.kurzweilai.net

Read more »

Pope's astronomer says he would baptise an alien if it asked him

An alien – 'no matter how many tentacles it has' – could have a soul, says pope's astronomer

Aliens might have souls and could choose to be baptised if humans ever met them, a Vatican scientist said today. The official also dismissed intelligent design as "bad theology" that had been "hijacked" by American creationist fundamentalists.

Guy Consolmagno, who is one of the pope's astronomers, said he would be "delighted" if intelligent life was found among the stars. "But the odds of us finding it, of it being intelligent and us being able to communicate with it – when you add them up it's probably not a practical question."

Speaking ahead of a talk at the British Science Festival in Birmingham tomorrow, he said that the traditional definition of a soul was to have intelligence, free will, freedom to love and freedom to make decisions. "Any entity – no matter how many tentacles it has – has a soul." Would he baptise an alien? "Only if they asked."

Consolmagno, who became interested in science through reading science fiction, said that the Vatican was well aware of the latest goings-on in scientific research. "You'd be surprised," he said.

The Pontifical Academy of Sciences, of which Stephen Hawking is a member, keeps the senior cardinals and the pope up-to-date with the latest scientific developments. Responding to Hawking's recent comments that the laws of physics removed the need for God, Consolmagno said: "Steven Hawking is a brilliant physicist and when it comes to theology I can say he's a brilliant physicist."

Consolmagno curates the pope's meteorite collection and is a trained astronomer and planetary scientist at the Vatican's observatory. He dismissed the ideas of intelligent design – a pseudoscientific version of creationism. "The word has been hijacked by a narrow group of creationist fundamentalists in America to mean something it didn't originally mean at all. It's another form of the God of the gaps. It's bad theology in that it turns God once again into the pagan god of thunder and lightning."

Consolmagno's comments came as the pope made his own remarks about science this morning at St Mary's University College in Twickenham. Speaking to pupils, he encouraged them to look at the bigger picture, over and above the subjects they studied. "The world needs good scientists, but a scientific outlook becomes dangerously narrow if it ignores the religious or ethical dimension of life, just as religion becomes narrow if it rejects the legitimate contribution of science to our understanding of the world," he said. "We need good historians and philosophers and economists, but if the account they give of human life within their particular field is too narrowly focused, they can lead us seriously astray."

The pope's astronomer said the Vatican was keen on science and admitted that the church had got it "spectacularly wrong" over its treatment of the 17th century astronomer Galileo Galilei. Galileo confirmed that the Earth went around the sun – and not the other way around – and was charged with heresy in 1633. He spent the rest of his life under house arrest in Tuscany. Only in 1992 did Pope John Paul admit that the church's treatment of Galileo had been a mistake.

Consolmagno said it was a "complete coincidence" that he was speaking at the British Science Festival at the same time as the papal visit.

Source <www.guardian.co.uk>

Read more »