Perineural invasion (PI) in skin cancers is a significant finding potentially requiring additional treatment. There are four levels of PI: perineural inflammation, minimal microscopic invasion of small nerves, larger nerve invasion, and invasion with clinical symptoms (pain, numbness, or motor deficits). With greater level of PI, there is a greater risk of recurrence, lymph node metastases, and distant metastases.
Neurotropism of cancer cells was at one time believed to be caused by the spread along perineural lymphatics. The current theory of perineural spread is based on the cleavage plane between the perineurium and the nerve ? an area of lower mechanical resistance to tumor spread.
Perineural spread is more common in tumors ?2.5 cm and in the head and neck area. The majority of perineural spread is < 1 cm while spread >2cm is unusual. The spread is believed to be continuous ? tumor ?skip areas? along the nerve are thought to be artifactual. However, some aggressive cancers can spread significant distance through perineural invasion as far as the skull base. In such cases the cancers also invade adjacent structures and can metastasize.
The incidence of perineural invasion for basal cell carcinomas is 1-6% and for squamous cell carcinomas 3-14%. Incidence is higher for spindle cell and adenosquamous cell variants. In fact, microcystic adnexal carcinoma (MAC), known for its silent subcutaneous spread, carries an 80% incidence of perineural spread.
The lowest level of perineural invasion is suggested by finding of perineural inflammation. Inflammation can be traced out microscopically to reveal perineural tumor cells in deeper sections. Several studies have shown that perineural in?ammation may serve as a marker for or even mask perineural invasion. This assertion is supported by the fact that over 60% of basal cell carcinomas exhibit moderate to heavy peritumoral infiltrate of helper T cells. Some authors have even suggested rapid immunohistochemistry staining with antihuman epithelial antigen (Ber-EP4) and cytokeratins to reveal BCC masked by inflammation.
The next level of PI is minimal microscopic invasion of small nerves <0.1mm. This is likely equivalent to the cases of perineural inflammation. Local recurrences rate with small caliber nerve involvement is up to 9%.
Large caliber nerve involvement by PI has been defined at ?0.1mm. The incidence of recurrence has been estimated as high as 50% and risk of death at 32%. Involvement of named nerves by PI is analogous to large caliber nerve involvement. Usually, large caliber nerve involvement is found in tumors larger than 2 cm, invading 1 cm or more, and poor histologic differentiation. 10-year local control rate of 62% has been reported.
Finally, perineural invasion with clinical symptoms of nerve involvement is another indicator of aggressive behavior and of poor prognosis. These symptoms include pain, numbness, paresthesias, and motor deficit. 10-year local control rate has been reported to be only 50%.
Treatment when perineural invasion is discovered must involve more aggressive surgery and occasionally radiation. When PI is found with Mohs surgery, removal of an additional surgical stage is recommended after tumor-free margins are obtained. Radiation therapy of the local area is indicated with larger caliber nerve (?0.1mm) or named nerve involvement. Radiation to the skull base or the involved cranial nerve ganglia is appropriate in these cases. Some argue to the futility of radiation because perineural tumor spread is slow and thus less amenable to radiotherapy. This decision can be modulated by the tumor behavior and its growth rate: the more rapid the tumor growth ? the more radiosensitive the tumor.
Perineural invasion can be an indicator of significant tumor extension, metastases, possible future recurrence, and decreased survival. In the first few years after treatment, close follow-up of these patients is required ? both with physical examination and with imaging.
References: Feasel, et al. Perineural Invasion of Cutaneous Malignancies. Dermatol Surg 2001; 27:6: 531-542.
Ratner, et al. Perineural Spread of Basal Cell Carcinomas Treated with Mohs Micrographic Surgery. Cancer 2000; 88:7: 1605-1613.
McCord MW, Mendenhall WM, Parsons JT, et al. Skin cancer of the head and neck with incidental microscopic perineural invasion. Int J Radiat Oncol Biol Phys 1999;43: 591?5.
McCord MW, Mendenhall WM, Parsons JT, et al. Skin cancer of the head and neck with clinical perineural invasion. Int J Radiat Oncol Biol Phys 2000;47:89?93.
Ross, et al. Diameter of Involved Nerves Predicts Outcomes in Cutaneous Squamous Cell Carcinoma. Dermatol Surg 2009; 35:12: 1859-1866.
Hassanein, et al. Peritumoral Fibrosis in Basal Cell and Squamous Cell Carcinoma Mimicking Perineural Invasion. Dermatol Surg 2005; 31:9 part 1: 1101-1106.
Cernea, et al. Perineural Invasion in Aggressive Skin Carcinomas of the Head and Neck. ORL 2009; 71:1: 21-26.
UNITED NATIONS (Reuters) - U.N. Secretary-General Ban Ki-moon plans to attend a summit meeting of leaders of non-aligned developing nations in Tehran next week, defying calls from the United States and Israel to boycott the event, U.N. diplomats said on Wednesday.
A spokesman for Iran's U.N. mission said it appeared that Ban would be attending the summit next week, though he declined to speak on behalf of the secretary-general's office.
Several other U.N. diplomatic sources said that barring any unexpected scheduling changes, Ban would attend the meeting of some 120 non-aligned nations in Tehran.
"It's a very important bloc of nations," a diplomatic source told Reuters on condition of anonymity. "Of course the SG (secretary-general) is going. He can't not go."
A Security Council diplomat said it was important for the secretary-general to go. He said Ban should not turn his back on the entire non-aligned movement because one member, Iran, happens to have a president who doubts the Holocaust and questions Israel's right to exist.
Ban's spokesman declined to comment.
Diplomats said they did not expect Ban to raise Iran's nuclear program, which Iran says is peaceful and Western powers and their allies fear is aimed at nuclear weapons, and its leaders' anti-Israeli remarks during his public speech during the non-aligned summit.
Such rebukes would be better left to Ban's expected private bilateral meeting with Iranian President Mahmoud Ahmadinejad in Tehran, envoys said.
The Tehran summit, which Egyptian President Mohamed Mursi will also attend, takes place Sunday through Friday. Mursi is the first Egyptian head of state to visit Tehran since the 1979 Islamic revolution.
BAN UNDER PRESSURE TO BOYCOTT SUMMIT
Earlier this month, Israeli Prime Minister Benjamin Netanyahu urged Ban to cancel his plans to participate in the Tehran non-aligned summit, according to Israeli media reports.
U.S. State Department spokeswoman Victoria Nuland made clear to reporters in Washington last week that the United States would also like the U.N. chief to boycott the event.
"The fact that the meeting is happening in a country that's in violation of so many of its international obligations and posing a threat to neighbors ... sends a very strange signal with regard to support for the international order, rule of law, et cetera," Nuland said.
"We've made that point to participating countries," she said. "We've also made that point to Secretary-General Ban Ki-moon."
Nuland added that if Ban does go, "we hope he will make the strongest points of concern."
Last week Ban sharply criticized Iranian Supreme Leader Ayatollah Ali Khamenei and President Mahmoud Ahmadinejad, describing their latest verbal attacks on Israel as "offensive and inflammatory.
Ahmadinejad said there was no place for the Jewish state in a future Middle East, echoing previous remarks he has made about Israel. He has also repeatedly called into question the Nazi extermination of Jews during World War Two - the Holocaust.
Khamenei said last week that Israel would one day be returned to the Palestinian nation and would cease to exist.
Separately, Alireza Miryousefi, spokesman for Iran's U.N. mission in New York, defended the Tehran summit in a letter to the editor of The Washington Post. He was responding to an editorial in the newspaper, which said Ban's presence in Tehran "will dignify a bacchanal of nonsense."
Miryousefi said the Post's editorial board "unjustifiably smeared Iran and mocked the upcoming Non-Aligned Movement summit in Tehran.
"By bringing dozens of world leaders together, the summit promises to make significant contributions to the movement's lofty objectives," he wrote.
OXFORD, Ohio (Reuters) - When Cesar Conda was a Republican staff director on the U.S. Senate's small business committee in 1991, he often was badgered with questions on economic theory by Paul Ryan, then a 21-year-old intern.
Ryan, now the Republican candidate for vice president, "worked in the mail room and would constantly pop his head into my office to ask questions about supply-side economics," Conda said. "I had a lot of work to do, so I gave him a couple of books to keep him busy."
Conda, now chief of staff for conservative Florida Senator Marco Rubio, lent Ryan Jude Wanniski's "The Way the World Works" (1978), which Conda called "the Bible" for the 1981 Kemp-Roth tax cut that lowered the top U.S. income tax rate to 50 percent from 70 percent. Conda also lent Ryan George Gilder's "Wealth and Poverty" (1981), which Conda says was a guide for President Ronald Reagan's supply-side economic policies of lowering taxes, slowing government growth and reducing regulation.
Ryan soon returned the Wanniski book, but Conda did not retrieve "Wealth and Poverty" until 2008, when he saw it in Ryan's Capitol Hill office. By then, Ryan was a five-term congressman from Wisconsin and the top Republican on the U.S. House budget committee.
"The margins were full of notes," added Conda, an economic adviser to the 2008 presidential campaign of Republican Mitt Romney, whom Conda introduced to Ryan in 2007.
Those who have known Ryan since the early 1990s describe a young man with a clear idea of his own political and economic philosophy. Ryan spent his formative years strengthening his grasp of supply-side economic theory.
Democratic opponents say that Ryan's austere budget plan -- which would carve into social programs that protect the poor such as food stamps and Medicaid health insurance -- is uncompromisingly cruel and based on an ideology of tax cuts and reduced regulation that, under former President George W. Bush, caused America's current economic woes.
Ryan and other Republicans reject that portrayal of the budget and its author.
Those in what Kansas Governor Sam Brownback calls Ryan's "band of brothers" -- like-minded Republican politicians and strategists from Reagan's tenure in the 1980s and Ryan's formative years in Washington in the 1990s -- say that while Ryan is committed to supply-side economics, he is capable of compromise on economic issues.
That would make Ryan more like Reagan than today's Republican hard-liners, who view Reagan as a conservative icon but typically reject the former president's penchant for compromising with Democrats.
Some recall conversations with Ryan in 2008 before Congress' votes to create the Troubled Asset Relief Program (TARP), the controversial bank bailout that cost taxpayers more than $400 billion. Ryan looked beyond his opposition to TARP because he realized the alternative was to subject America to an economic depression, these Ryan fans and supply-siders said.
"Paul is an eager, happy warrior on the battlefield of ideas," said Vin Weber, a former Minnesota congressman who was a co-director of the now-defunct conservative think tank Empower America, where Ryan worked in the 1990s. "He has strong beliefs, but he's driven by data. Paul knew without TARP in 2008 we would descend into another Great Depression, and I still think he did the right thing by voting for it."
'VISION QUEST'
During a 2009 commencement speech he gave at Miami University in Oxford, Ohio, where he graduated in 1992, Ryan referred to having had a "difficult" time in high school after his father's death.
He also mentioned an economics professor, Rich Hart.
"He provided me with much more than just an education in economics," Ryan said. "He provided a vision quest in my mind to improve the economy of our nation."
Hart, whose "intellectual hero" is economist Milton Friedman, had long conversations with Ryan and gave him a copy of Friedman's "Capitalism and Freedom."
Hart said he often has given students Ayn Rand's "Atlas Shrugged," a novel about a rebellion by citizens against high taxes and government regulation that Ryan has said had a great influence on him. Hart said Ryan already had read the book by the time Hart taught him.
"When Paul Ryan arrived at Miami he already had an economic and political philosophy," Hart said. "He spent his time here refining and strengthening it."
When Ryan went to Oxford in 2009, Hart says he tried to persuade his former student to run for president. He recalls Ryan saying no, that he did not want to leave his three young children to campaign for two years.
'MATURE BEYOND HIS YEARS'
While at Miami, Ryan interned for Republican U.S. Senator Bob Kasten of Wisconsin and for the Senate small business committee. Kasten said he offered Ryan a job after he graduated in 1992 and that Ryan "was always mature beyond his years."
But Kasten recalled a moment of youthful longing by Ryan. When Ryan got the job offer, he said he wanted to take a year off to be a ski instructor in Colorado. Ryan's mother, Elizabeth, insisted he seize the chance to work in Washington.
After Kasten lost to Democrat Russ Feingold in the 1992 election, Ryan joined Empower America, where he helped former congressman Jack Kemp, the co-author of the 1981 tax cut and Empower America's co-director for economic policy.
Founded after Democrat Bill Clinton won the 1992 presidential election, Empower America was intended to compete with Democrats "on the battlefield of ideas," Weber said. The think tank featured economists such as Arthur Laffer, one of Reagan's economic advisers.
Empower America later merged with Citizens for a Sound Economy, which later split into FreedomWorks and Americans for Prosperity, the latter of which has backing from oil and gas billionaire brothers Charles and David Koch.
Ryan was very close to Kemp, who briefly sought the 1988 Republican presidential nomination and was Bob Dole's vice presidential running mate in 1996.
Weber said that Kemp, who died in 2009, "was the great hope for many of us after Reagan because for conservatives of my ilk he best embodied Reagan's policies.
"After Kemp, Paul Ryan emerged as our next great hope," he added.
Some have portrayed Kemp as a second father to Ryan, but Kasten says that is not quite accurate.
Kasten said Ryan has had several brother-type relationships with like-minded conservatives such as Kasten, "based on mutual respect and love."
'HE'S VERY SHARP'
Conda introduced Ryan to Romney in Ryan's office January 2007. What was supposed to be a courtesy meeting quickly became something more.
"Before long they were talking about entitlement reform and marginal income taxes," he said. "Afterwards, Romney said to me, 'I like him; he's very sharp.' "
Apart from sharing an apparent affinity for tax and economic theory, some who know Ryan say he and Romney are both compromisers.
"There are some people who can be a committed conservative and agree with all the ideas, but still be an individual," said Linda Killian, a journalist who chatted with Ryan several times in the mid-1990s for her book "The Freshmen: What Happened to the Republican Revolution?" -- an account of the two years after Republicans took control of Congress for the first time in four decades in 1994.
Ryan is "certainly no partisan robot," Killian said.
But Congressman Chris Van Hollen, the top Democrat on the House Budget Committee, said that although Ryan is personable, "you should not confuse congeniality with an ability to compromise."
"Paul Ryan is a passionate advocate of trickle-down economics that have failed the test of reality," Van Hollen said. "There is no compromise in his budget plan. It's a take-it-or-leave-it proposition with a totally lopsided approach to the budget and the economy."
Conservatives who know Ryan well point to his vote for TARP as an example of his ability to compromise on economic issues.
The bank bailout is anathema to Tea Party activists, who have targeted those who supported it such as Indiana Senator Dick Lugar, who lost a primary election in May.
In 2008 Ryan said in the U.S. House that although TARP was against his principles he would support it "to save" the free-market system.
"Paul Ryan is not a dogmatic, blind conservative," Kasten said. "He's made a number of compromises and will continue to do so."
2012 Olympic gold medalist Ryan Lochte was spotted hosting a pool party to celebrate his belated 28th birthday at Azure at The Palazzo Hotel and Casino in Las Vegas, Nevada on Saturday (August 18, 2012). The American swimmer hit the bash with fellow Olympic swimmers Conor Dwyer and Cullen Jones, spending the day in a private cabana in the secluded luxury pool club. Heartthrob Ryan, who wore board shorts with black and white stars and stripes with loafers and one of his gold medals from the London Games around his neck, happily posed for photographs with his two friends on the blue carpet. The bachelor then traded in his modest swimsuit for a bright pink speedo, kicking off the party, popping champagne and mingling with ladies in the pool. Ryan Lochte must have been in great spirits, purely pleasure because he was surrounded by bikini-clad women at the celebration inside Azure.
11-time Olympic medalist Ryan Lochte poses with his medal at Azure at The Palazzo on Saturday (August 18, 2012).
Ryan Lochte pops champagne to kick off the party.
The Olympian was pictured being surrounded by an array of bikini babes at a pool party, held at TAO Beach in Las Vegas on Friday (August 17, 2012). Hunky Ryan Lochte slipped into a skimpy white speedo for some poolside fun, posing with some bikini-clad models. The Olympian hottie and his teammates Cullen Jones and Conor Dwyer, as well as 90210's Matt Lanter and Chelsea Lately's Ryan Basford then headed to Lavo restaurant to enjoy their dinner before hitting the night life scene.
Ryan Lochte shows off his guns at his pool party at TAO Beach in Las Vegas on Friday (August 17, 2012).
The Olympic champ is surrounded by a plethora of bikini babes. Ryan is in great spirits and takes photos with some hot girls who come up to meet him.
In a recent interview, the ?90210? guest star admits that he's looking for something beyond the superficial when it comes to a girlfriend. "I'm always looking for the perfect girl. Now that I'm older, I?m looking to settle down a bit." Ryan further elaborates on the qualities he wants in a significant other: "Anyone that can make me smile and make me laugh. That's the key to my heart."
Ryan Lochte shows off his hot body in a tiny white Speedo.
Related links:
Michael Phelps? model girlfriend Megan Rossee is ?not with him to be famous?
Michael Phelps parties with girlfriend Megan Rossee after winning the 22th medals at the 2012 London Olympics
Michale Phelps and girlfriend Megan Rossee make their red-carpet debut together (Pictures)
Showtime?s documentary series ?The Franchise? followed the Giants last season and the Marlins this season, but the network has decided to cancel this year?s version after just seven episodes.
It was supposed to go at least eight episodes, but both sides agreed to cut it short after Showtime declined to broadcast any more than the initial allotment with the Marlins currently in last place at 55-67.
Or as Marlins president David Samson told Joe Capozzi of the Palm Beach Post: ?There was an option to do more but given the state of our season, it was decided that the original eight would suffice.?
Sure, the Marlins are really bad, but I think it was HBT?s own Drew Silva making a cameo appearance that ultimately caused Showtime to pull the plug.
Hey guys! So over the past days I have been putting about 3 posts together and I really hope you enjoy part 1! Here it goes.....
Hasn't the Wizard101 Community always wanted fishing in Wizard101?
In Wizard101 almost everybody has seen the fishing evidence in Grizzleheim. And we have all seen the Wizard Frog Fish Thing.? As we all think, Fishing will be like Gardening, Crafting, or Pet Training. But Wizard101 already has 3 solid as I like to call them, "Alternatives". I have no idea if Pirate101 has Pet Training, Gardening, or Crafting but I do know Fishing would be great for us Pirates to do on our boats. My idea was that our Companions could steer the ship to your next destination in the Skyway as you fish a couple for a minutes.? Also in Wizard101 we have seen Fish Items! Like the Shark Mount, Koi Fish, Spiny Fish, and all the other fish in Celestia, etc. I am also for certain KI will make more Sea Creature, pets or mounts too.? Remember the squid mount? Maybe this is where it will debut! Now, if you were to catch a fish, what would you do with them? But it in your own aquarium! You've seen aquariums in Wizard101, like the?craft-able?aquarium, the aquarium in Stone Town, and the aquarium in the Storm House! Now if Wizard101 had all of the pieces to make a Fishing feature, why wouldn't they make it already? Why would they take time to make a new Pet feature in Wizard101 with the ability to train your pet to Mega, and make two new Pet Games? Why would KI make concept art for a squid and never use it? At the time Wizard101 made the squid concept, Celestia was about to come out in Test Realm! I think they had allot of other work to do than draw up something they?wouldn't?make in years. If your still following me, I am leading up to that they will try fishing in Pirate101. Personally I?don't?think a?business?like KI would waste time to put detail a guy fishing in Grizzleheim for nothing. Now for your voice! Leave a comment or send me an email and I'll give YOU my opinion here in my next blog post (unless you?don't?want me to XD), and I guess I'll try and send out some codes!?
Next generation 3-D theater: Optical science makes glasses a thing of the pastPublic release date: 20-Aug-2012 [ | E-mail | Share ]
Contact: Angela Stark astark@osa.org 202-416-1443 Optical Society of America
WASHINGTON, Aug. 20From the early days of cinema, film producers have used various techniques to create the illusion of depth with mixed results. But even with digital technology, the latest Hollywood blockbusters still rely on clunky glasses to achieve a convincing 3-D effect.
New optics research by a team of South Korean investigators offers the prospect of glasses-free, 3-D display technology for commercial theaters. Their new technique, described in a paper published today in the Optical Society's (OSA) open-access journal Optics Express, can bring this added dimension while using space more efficiently and at a lower cost than current 3-D projection technology.
"There has been much progress in the last 10 years in improving the viewers' experience with 3-D," notes the team's lead researcher Byoungho Lee, professor at the School of Electrical Engineering, Seoul National University in South Korea. "We want to take it to the next step with a method that, if validated by further research, might constitute a simple, compact, and cost-effective approach to producing widely available 3-D cinema, while also eliminating the need for wearing polarizing glasses."
Polarization is one of the fundamental properties of light; it describes how light waves vibrate in a particular directionup and down, side-to-side, or anywhere in between. Sunlight, for example, vibrates in many directions. To create modern 3-D effects, movie theaters use linearly or circularly polarized light. In this technique, two projectors display two similar images, which are slightly offset, simultaneously on a single screen. Each projector allows only one state of polarized light to pass through its lens. By donning the familiar polarized glasses, each eye perceives only one of the offset images, creating the depth cues that the brain interprets as three dimensions.
The two-projector method, however, is cumbersome, so optical engineers have developed various single projector methods to achieve similar effects. The parallax barrier method, for example, succeeds in creating the illusion of 3-D, but it is cumbersome as well, as it requires a combination of rear projection video and physical barriers or optics between the screen and the viewer. Think of these obstructions as the slats in a venetian blind, which create a 3-D effect by limiting the image each eye sees. The South Korean team has developed a new way to achieve the same glasses-free experience while using a single front projector against a screen.
In their system, the Venetian blinds' "slat" effect is achieved by using polarizers, which stop the passage of light after it reflects off the screen. To block the necessary portion of light, the researchers added a specialized coating to the screen known as a quarter-wave retarding film. This film changes the polarization state of light so it can no longer pass through the polarizers.
As the light passes back either through or between the polarizing slates, the offset effect is created, producing the depth cues that give a convincing 3-D effect to the viewer, without the need for glasses.
The team's experimental results reported today show the method can be used successfully in two types of 3-D displays. The first is the parallax barrier method, described above, which uses a device placed in front of a screen enabling each eye to see slightly different, offset images. The other projection method is integral imaging, which uses a two-dimensional array of many small lenses or holes to create 3-D effects.
"Our results confirm the feasibility of this approach, and we believe that this proposed method may be useful for developing the next generation of a glasses-free projection-type 3-D display for commercial theaters," notes Lee.
As a next step in their research, the team hopes to refine the method, and apply it to developing other single-projector, frontal methods of 3-D display, using technologies such as passive polarization-activated lens arrays and the lenticular lens approach.
While their experimental results are promising, it may be several years until this technology can be effectively deployed in your local movie theater for you to enjoy without polarizing glasses.
###
Paper: "A frontal projection-type three-dimensional display," Optics Express, Vol. 20, Issue 18, pp. 20130-20138 (2012). http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-20-18-20130
EDITOR'S NOTE: High-resolution images are available to members of the media upon request. Contact Angela Stark, astark@osa.org.
About Optics Express
Optics Express reports on new developments in all fields of optical science and technology every two weeks. The journal provides rapid publication of original, peer-reviewed papers. It is published by the Optical Society and edited by C. Martijn de Sterke of the University of Sydney. Optics Express is an open-access journal and is available at no cost to readers online at http://www.OpticsInfoBase.org/OE.
About OSA
Uniting more than 130,000 professionals from 175 countries, the Optical Society (OSA) brings together the global optics community through its programs and initiatives. Since 1916 OSA has worked to advance the common interests of the field, providing educational resources to the scientists, engineers and business leaders who work in the field by promoting the science of light and the advanced technologies made possible by optics and photonics. OSA publications, events, technical groups and programs foster optics knowledge and scientific collaboration among all those with an interest in optics and photonics. For more information, visit www.osa.org.
[ | E-mail | Share ]
?
AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.
Next generation 3-D theater: Optical science makes glasses a thing of the pastPublic release date: 20-Aug-2012 [ | E-mail | Share ]
Contact: Angela Stark astark@osa.org 202-416-1443 Optical Society of America
WASHINGTON, Aug. 20From the early days of cinema, film producers have used various techniques to create the illusion of depth with mixed results. But even with digital technology, the latest Hollywood blockbusters still rely on clunky glasses to achieve a convincing 3-D effect.
New optics research by a team of South Korean investigators offers the prospect of glasses-free, 3-D display technology for commercial theaters. Their new technique, described in a paper published today in the Optical Society's (OSA) open-access journal Optics Express, can bring this added dimension while using space more efficiently and at a lower cost than current 3-D projection technology.
"There has been much progress in the last 10 years in improving the viewers' experience with 3-D," notes the team's lead researcher Byoungho Lee, professor at the School of Electrical Engineering, Seoul National University in South Korea. "We want to take it to the next step with a method that, if validated by further research, might constitute a simple, compact, and cost-effective approach to producing widely available 3-D cinema, while also eliminating the need for wearing polarizing glasses."
Polarization is one of the fundamental properties of light; it describes how light waves vibrate in a particular directionup and down, side-to-side, or anywhere in between. Sunlight, for example, vibrates in many directions. To create modern 3-D effects, movie theaters use linearly or circularly polarized light. In this technique, two projectors display two similar images, which are slightly offset, simultaneously on a single screen. Each projector allows only one state of polarized light to pass through its lens. By donning the familiar polarized glasses, each eye perceives only one of the offset images, creating the depth cues that the brain interprets as three dimensions.
The two-projector method, however, is cumbersome, so optical engineers have developed various single projector methods to achieve similar effects. The parallax barrier method, for example, succeeds in creating the illusion of 3-D, but it is cumbersome as well, as it requires a combination of rear projection video and physical barriers or optics between the screen and the viewer. Think of these obstructions as the slats in a venetian blind, which create a 3-D effect by limiting the image each eye sees. The South Korean team has developed a new way to achieve the same glasses-free experience while using a single front projector against a screen.
In their system, the Venetian blinds' "slat" effect is achieved by using polarizers, which stop the passage of light after it reflects off the screen. To block the necessary portion of light, the researchers added a specialized coating to the screen known as a quarter-wave retarding film. This film changes the polarization state of light so it can no longer pass through the polarizers.
As the light passes back either through or between the polarizing slates, the offset effect is created, producing the depth cues that give a convincing 3-D effect to the viewer, without the need for glasses.
The team's experimental results reported today show the method can be used successfully in two types of 3-D displays. The first is the parallax barrier method, described above, which uses a device placed in front of a screen enabling each eye to see slightly different, offset images. The other projection method is integral imaging, which uses a two-dimensional array of many small lenses or holes to create 3-D effects.
"Our results confirm the feasibility of this approach, and we believe that this proposed method may be useful for developing the next generation of a glasses-free projection-type 3-D display for commercial theaters," notes Lee.
As a next step in their research, the team hopes to refine the method, and apply it to developing other single-projector, frontal methods of 3-D display, using technologies such as passive polarization-activated lens arrays and the lenticular lens approach.
While their experimental results are promising, it may be several years until this technology can be effectively deployed in your local movie theater for you to enjoy without polarizing glasses.
###
Paper: "A frontal projection-type three-dimensional display," Optics Express, Vol. 20, Issue 18, pp. 20130-20138 (2012). http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-20-18-20130
EDITOR'S NOTE: High-resolution images are available to members of the media upon request. Contact Angela Stark, astark@osa.org.
About Optics Express
Optics Express reports on new developments in all fields of optical science and technology every two weeks. The journal provides rapid publication of original, peer-reviewed papers. It is published by the Optical Society and edited by C. Martijn de Sterke of the University of Sydney. Optics Express is an open-access journal and is available at no cost to readers online at http://www.OpticsInfoBase.org/OE.
About OSA
Uniting more than 130,000 professionals from 175 countries, the Optical Society (OSA) brings together the global optics community through its programs and initiatives. Since 1916 OSA has worked to advance the common interests of the field, providing educational resources to the scientists, engineers and business leaders who work in the field by promoting the science of light and the advanced technologies made possible by optics and photonics. OSA publications, events, technical groups and programs foster optics knowledge and scientific collaboration among all those with an interest in optics and photonics. For more information, visit www.osa.org.
[ | E-mail | Share ]
?
AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.
.png)
.png)
![[ Back to EurekAlert! ]](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_sGOAK9-TF7QNk4Ocx-INeA5pebBhebN4wk1am4pL2uJrPXCNIy80Gr26VGWp1iTxogxZJnptaF09nrND-vUfnNvM9rpU1rrkOCsOvaW7Q=s0-d){kind=small}
Public release date: 20-Aug-2012
Share ]