FOR years, Holocaust survivor Pinchus Gutter has told the tragic story of watching his parents and 10-year-old twin sister herded into a Nazi death camp's gas chambers.

He's carried this horrific image with him for 70 years - that of his sister vanishing into a sea of people doomed to die.

Only this time a digital doppelganger of the 80-year-old survivor has recounted the horror of the Holocaust to an audience gathered in an auditorium at the University of Southern California's School of Cinematic Arts.

Over the years, elderly Holocaust survivors like Gutter have been leaving behind manuscripts and oral histories of their lives, fearful that once they are gone there will be no one to explain the horror they lived through or to challenge the accounts of Holocaust deniers like Iranian President Mahmoud Ahmadinejad.

So, for 18 months, a group led by USC's Shoah Foundation has been creating three-dimensional holograms of nearly a dozen people who survived Nazi Germany's systematic extermination of six million Jews during World War II, so the stories can endure.

Like the digital librarian in the 2002 movie The Time Machine, the plan is for Gutter and the others to live on in perpetuity, telling generations not born yet of the horror they witnessed and offering their thoughts on how to prevent a repeat of one of history's darkest moments.

Gutter's hologram is only a two-dimensional figure at present but he has been painstakingly filmed for hours in 3-D.

By next year his hologram could be talking face-to-face with visitors at the US Holocaust Memorial Museum in Washington, DC.

It's a certainty within five years, says Stephen Smith, the Shoah Foundation's executive director, and Paul Debevec, associate director of the university's Institute for Creative Technologies, which is creating the hologram project's infrastructure.

"It's clear this will happen," said Debevec, whose institute has worked with Hollywood on such films as Avatar and The Curious Case of Benjamin Button, winning a special Academy Award for the latter.

Indeed, it already has almost happened.

More than 15 years after his death, rapper Tupac Shakur made a 3-D hologram-like appearance at last year's Coachella Valley Music and Arts Festival, performing alongside a real Snoop Dogg.

Technically, Shakur wasn't a hologram, however, because his image was projected onto a thin screen that was all but invisible to the audience.

"This takes it one step further as far as you won't be projecting onto a screen, you'll be projecting into space," Smith said of the project, called New Dimensions in Testimony.

It comes just in time, said Rabbi Marvin Hier, director of the Simon Wiesenthal Center, which is dedicated to keeping alive the history of the Holocaust.

"This generation is coming to an end, unfortunately," Hier said of Holocaust survivors, whose average age is estimated at 79.

"Within the next decade or so there won't be many survivors alive anywhere in the world."

Given the prominence of Holocaust deniers like Iran's Ahmadinejad, Hier said, it's crucial to record survivors' accounts in a way that future generations can easily access and relate to.

Eventually, according to Debevec and other researchers, holograms could have numerous uses.

They could be teaching classes, taking part in business conferences and providing expert opinion on subjects when real people can't be there to do so.

Perhaps Gutter's digital presence summed up the reason for that best when it was asked the other day why he chose to take part.

It replied: "I tell my story for the purpose of improving humanity."