Sunday, May 2, 2010

So You Think You Can Be Princess Leia?

“Help me, Obi-Wan Kenobi; you’re my only hope,” might have crossed your mind if you thought about going to see the MIT Museum’s holography collection through the Cambridge Science Festival’s “Explore Holography” event. Perhaps you decided to go because you were excited at the prospect of being able to don your Princess Leia costume and reenact that famous scene. And maybe, you were completely disappointed when you finally saw what the Museum meant by “holograms.” The truth is, most of what you see in the news and media claiming to be holograms actually aren’t real holograms. Sure, they might provide some cool 3D visuals, but they’re not done using the holographic technology that I discussed in my previous two blog posts.

Most of what we think we know about holography comes from television and movies. If you’re like me, you probably watched the original Star Wars Episode IV: A New Hope and saw the scene where R2D2 plays back a “holographic” video of Princess Leia’s plea for Obi-Wan Kenobi’s help. The robot projected the video in the middle of thin air, which was marvelous – but the result of computerized special effects post-production, not holography. Fast forward a few years, and we’re watching CNN’s coverage of the 2008 US presidential election. Wolf Blitzer “beamed” Jessica Yellin, a news correspondent who was in Chicago at the time, into the New York studios to have a “face-to-face” chat via “hologram.” However, it wasn’t a real hologram. A hologram needs to be projected from a medium; it can’t just float in air. Yellin even revealed the magic behind the illusion: she was standing in a tent with 35 cameras arranged in a circle pointing at her. Each camera captured one perspective of her body and fed the video to a cluster of 20 computers to crunch the data and send to the studios in New York to project onto blue screens. Blitzer couldn’t actually see Yellin in real time; he was actually talking to a blue screen and watching monitors that had the video of Yellin inserted into the video of him. Hardly holography. The same thing is true of the movies Minority Report and Iron Man, where Tom Cruise and Robert Downey Jr. didn’t need computer screens because they were able to interact with the information in a hologram that floated in midair. Also not real holograms.

After seeing what real holograms look like, you might be reminded of those 3D movies that you have to wear a pair of red and blue glasses to watch. They seem pretty similar, right? The images seem like they’re literally popping out of the screen, but they don’t use the same technology at all. To make those movies, each frame is rendered in red and blue, each of which is a slightly different viewing perspective of the same object. Why the different perspectives? Well, it’s based on how the brain processes visual information. Your eyes are spaced about two to three inches apart, so each eye captures a slightly different perspective of an object. Your brain combines the two images so that you can see the object in three dimensions. 3D movies do the same thing and overlay the two images. When the light hits your red and blue glasses, each lens filters out one of the colors (red lens filters out red light so that your eye receives only the blue light, and vice versa). As a result, your eyes and brain get two images from different angles, so the film looks 3D. This method is actually an illusion and can’t be considered holographic technology.

Lastly, you may have seen or heard of “touchable holography,” which is a technology that some researchers at the University of Tokyo developed in the fall of 2009. This technology adds a tactile dimension to holograms. The researchers claim that viewers cannot interact with traditional holography. To change this, they use Wii remotes to sense the motions of a viewer and move the hologram accordingly. To make the viewer feel the hologram, a beam of ultrasonic waves is directed at the viewer, which generates pressure on the surface of the viewer’s body. While all this is exciting technology, it cannot be called true holography. What the researchers call a “hologram” is actually an illusion made with some curved mirrors. An LCD projector projects an image onto the mirrors, which reflect the light to a point close to the viewer, so the image appears as if it were 3D and floating in air.

Hopefully, I’ve dispelled some common misconceptions about what a hologram is and isn’t. Holography has great promise for the future (e.g. data storage and true holographic video), but it won’t be quite like the things we’ve seen in sci-fi movies or even TV news shows. If you have any questions about holography in general, feel free to leave a comment!

Saturday, May 1, 2010

Questions with No Answers

I live-tweeted while watching the webcast of "Big Ideas, Busy People" on Friday, April 23. "Big Ideas, Busy People" was a brand new event during the Cambridge Science Festival where ten lecturers presented 5-minute presentations with a 5-minute question and answer session afterwards. It was a perfect event to live-tweet, as that helped me remember the many points made that evening. It was definitely easy to get lost in a concept, and then lose track of the presentation. I wanted to blog a post-festival write-up of this event right away, but then I attended "Lunch with a Laureate" on Monday, April 30th. Robert Merton, the 1997 Nobel Prize winner in Economics, was speaking.

So many ideas were thrown out during both events that I feel I might end up condensing too much if I try to write a post-festival blog post from my notes. My tweets are still available from "Big Ideas, Busy People," and the recorded event will soon be available at MIT World. Merton's talk should also be fed online. Since both events will be available electronically, it might be futile to try to summarize them. Thus, I decided it would be more useful to discuss asking questions at public events.

I noticed audience members seemed frustrated at either event if the speaker couldn't give a direct answer. With all the questions that the speakers were asked, I don't blame them for not answering overly-specific questions with little relevance to their research. For example, Merton's research, which won him the Nobel Prize, is largely related to options pricing modeling and derivatives. However, Merton was asked a very specific question by an audience member, "What do you think should be done with investing in China?" Merton prefaced his answer, "when you win the Nobel Prize, people expect you have answers on everything; I have ideas that doesn't mean they're right." This was a polite way for him to avoid saying too much, since his idea was just an opinion, not necessarily based on all the facts.

A similarly overly-specific question happened at "Big Idea, Busy People," when Professor Mark Hauser was unable to answer a question on whether or not Amy Bishop was evil. He did not even follow the court case, and he reminded the audience that he was not a clinician and thus unable to professionally make those judgments.

I was always taught and firmly believe there is no such thing as a stupid question. However, some questions are best not asked at a large events that are under time-constraints. At both events I attended, others were dying to pose questions that possibly could be answered.

This reminds me of a time, I attended a review session for a class, and the teacher responded to a question with the line, "this is not going to be tested." The student persisted with her question, even given the response, and the whole class stayed an extra hour as a result. We lost valuable time that could've been spent learning concepts of relevance to the test. The student's question was meant for Office Hours, where students can ask general questions one-on-one with the instructor, and it was not appropriate for a Review Session, where the sole purpose is to prepare for an upcoming test. If a question doesn't have relevance to the audience, especially in timed-events, it's better to move on. This may sound rude, but the intentions are not to offend the questioners. It's to give others the opportunity to ask their questions.

Good questions at these events are concise and to the point. As John Durant put it in the beginning of "Big Ideas, Busy People," questions should be twitter-style contributions (i.e. 140 characters) with a question mark at the end. Specific questions are harder to answer. The best indication your question is too specific is when you have to preface it with lengthy remarks so the audience can follow along. You can still ask questions relevant to your curiosity without telling the audience your life story and why you want to know the answer. If concise and relevant, the speaker should be able to answer the question quickly. An example of a good question happened at "Big Ideas, Busy People" when a ten-year old asked a question about string theory and 11 dimensions; Lisa Randall, the speaker, was able to answer the ten-year old's question in less than a minute because it was concise. Another way to ask good questions is when the professor hints he or she wants the question. Lisa Randall told the audience to ask her about Brain World, a universe that goes beyond 3-dimensions, and when someone did, she was thrilled to discuss it.

It's exciting to see esteemed professors give insightful lectures. This excitement comes with responsibility though as it's also important to be considerate of those around you when asking your questions. When there's only five-minutes to answer questions, you should really be asking questions that the professor can answer briefly and wants to answer.

"Big Ideas for Busy People" and "Lunch with a Laureate" are throught-provoking events where audience members ask many questions. Sometimes, questions with no answers are better to be debated amongst friends. After watching Mark Hauser speak on, "what is evil," I found myself asking my friends whether or not they thought bullies were evil after watching the Simpson's on a Sunday evening. This sparked a long, insightful discussion that a 10-minute limit would've drastically hindered. If you didn't get your question answered at the event, try asking your friends: you might end up surprised at how much you can learn from just talking to others.