Chapter 9 3. Paradoxical modification and repeated modification in virtual reality

Mike Hammer (the world's leading corporate doctor or so-called "corporate image reengineering engineer") describes "corporate change" as an oxymoron that almost becomes repetitive (a big company with a solid foundation needs change!) .The so-called "repetitive modification" refers to repetitive and cumbersome expressions such as "in one's own mind"; while oxymoron refers to obvious contradictory combinations such as "artificial intelligence" or "airplane food".Whether repetition and oxymoron are the exact opposite is up for debate, but if we were to give out an award for "best oxymoron," the term "virtual reality" would be on the list.

If we regard the two parts of "virtual" and "real" that make up the word "virtual reality" as "equal halves", then it seems more reasonable to regard "virtual reality" as a concept that is repeatedly modified.Virtual reality can make man-made things as real as real things, or even more real than real things. For example, flight simulation, the most complex and longest-running virtual reality application, is more realistic than flying a real airplane.The reason why newly trained but well-trained pilots can fly a "real" Boeing 747 full of passengers at the first try is that they learn driving skills in flight simulators better than they do. Learn faster and more on a real plane.In the simulator, pilots are exposed to all the rare situations that might not arise in the real world, including planes nearly colliding or breaking into pieces.

Another virtual reality application with social significance is driving training in driving schools.If you've never experienced this before, you never know how you'll react when a child suddenly runs between two cars on a slippery road.Virtual reality allows us to experience various possible situations "in person".The idea behind immersive virtual reality is to give people the feeling of being “in the middle of the action” by allowing the eyes to receive information that would only be received in the real situation, and more importantly, the image you see It will change instantly as your viewpoint changes, which further enhances the dynamics of the scene.Our perception of real space comes from a variety of visual cues, such as the relative volume, brightness, and motion of objects at different angles.One of the strongest cues comes from binocular perspective, which is particularly powerful when used simultaneously because the left and right eyes see different images.Combining these different images into a three-dimensional image forms the basis of stereo vision.

Each eye's depth perception is slightly different, causing the two eyes to see different images.This phenomenon is called parallax.The effect of parallax is most pronounced when viewing objects at close range (say within 6 feet).Objects that are farther away basically cast the same image on both eyes.Have you ever wondered why there are always a lot of back and forth movements in close range in stereoscopic movies?Why do objects in the film keep flying towards the audience?Because those movements are designed to be within the best effect distance of stereoscopic images. A typical prop for virtual reality is a helmet with two goggle-like displays, one for each eye.Each monitor shows a slightly different perspective image, exactly as it would appear if you were there.When you turn your head, the image updates at such a rapid rate that it feels as if the image shifts because of your head turning (rather than the computer actually tracking your movement, which is true) .You think you are the cause of the change, not an effect that has been processed by the computer.

The degree of realism of the visual experience is determined by two factors.One is the quality of the image, that is, the number of edges and structures between them displayed in the image, the more the number, the better the quality.The second is the response time, that is, the speed at which the screen is updated. The faster the speed, the better, and the shorter the response time, the better.Both of these variables require a very powerful computer. Until recently, such powerful computers were not available to most product developers, but that has just changed. Virtual reality technology was born as early as 1968, when the first head-mounted display system was successfully manufactured by Ivan Sutherland.Later, research by NASA and the Department of Defense led to the development of some expensive virtual reality prototypes for space exploration and military applications.Virtual reality is particularly suitable for training tanks and submarines, because in "real" warfare, it is also necessary to view the outside world through binoculars or periscopes.

Until today, when we have powerful and low-cost computers, it is not possible to use virtual reality technology as a medium for consumer entertainment purposes.And in the new face of virtual reality, there's absolutely no shortage of frightening shots.Jurassic Park Adventure "Jurassic Park" allows you to experience the amazing effects of virtual reality.But unlike the movie or book of the same name, in the virtual reality Jurassic Park, there is no main story line.Here, Michael Crichton's task, like a stage designer or playground designer, is to give each dinosaur a different look, personality, actions and purpose.After the simulated dinosaurs move, you walk among them.It's not TV, and it doesn't have to be like spotless Disneyland.There are no crowds, no long lines, no smell of popcorn, just dinosaur droppings.It's like stepping into a prehistoric jungle, and it can appear more dangerous than any real jungle.

Future adults and children alike can entertain themselves in this way.Since these illusions are all generated by computer processing and are not real situations, there is no need to be limited by the size of the real thing or the place where it takes place.In virtual reality, you can open your arms, embrace the galaxy, swim in human blood, or visit Alice in Wonderland. Current virtual reality has a number of shortcomings and technical lapses that must be overcome before it can gain wider appeal.For example, low-cost virtual reality is plagued by stepped irregular graphics.When the image is moving, the jagged patterns appear more unstable because they appear to be moving, but not necessarily in the same direction as the frame.Think about what the horizon looks like, a very straight horizon.Now tilt it a little bit, and there's a zigzag in the center of the horizontal line, and then tilt it a little more, and there's a second, third, and more zigzags.The jaggies seem to move until the line finally tilts at a 45-degree angle, and the jaggies of adjacent pixels on the line form a staircase, one next to the other, which is just ugly.It's always slow. Worse than that, virtual reality isn't fast enough.All commercial systems, especially the upcoming new products of many video game manufacturers, have the problem of being slow.When you turn your head, the image changes quickly, but not fast enough.The image always takes half a beat to appear.

When 3D computer graphics first appeared, people used all kinds of stereoscopic glasses to achieve viewing effects. Sometimes they were cheap polarized lenses, and sometimes they were more expensive electronic shutters, which would allow the eyes to receive different images in turn.I also remember the first time I operated a device like this, everyone -- not most people, but literally everyone -- put on the glasses for the first time in their lives and saw three-dimensional images on the screen. After viewing the image, they will turn their heads around, wanting to see how the image changes.The result is the same as watching a stereoscopic movie, the image has not changed.Turning your head around doesn't help.

This natural "twist your neck" response says it all.Virtual reality must work closely with sensing the user's movement and location, allowing the viewer to induce changes in the image, rather than being fully controlled by the machine.Nothing is more important than the computer's ability to track head movements and respond to its rapid changes.The speed of image update (frequency response) is actually more important than the resolution.This shows how sensitive our motor nervous system is, and even the slightest sluggishness can spoil the entire sensory experience. Most manufacturers would probably ignore this entirely, and market early high-resolution virtual reality systems that desperately emphasized graphics.The result of this is to sacrifice responsiveness.In fact, if they reduce the graphics display, enhance the anti-aliasing technology of the image, and improve the response speed, then the virtual reality experience they provide will be more satisfactory.

Another approach is to completely abandon the head-mounted display that provides different perspective images for the left and right eyes, and instead use so-called autostereoscopic effect technology, which makes real objects or holographic images appear in the air, so that both eyes can watch together. Star Wars and Holography Sometime in the next 1,000 years, our grandchildren or great-grandchildren will be watching football (if it's still called that) in a new way.They'll move around the coffee table (if it's still called that), let 8-inch players gallop around the living room (if it's still called that), and kick half-inch footballs around.

This model is the complete opposite of early VR ideas.No matter which angle you view it from, you can enjoy extremely high resolution.Wherever you look, you see three-dimensional pixels floating in space. In the "Star Wars" (Star Wars) movie, R2D2 used this method to project the image of Princess Leia on the floor of Obi-Wan.The beautiful princess becomes a ghostly phantom projected in space, visible (in principle) from any angle.This special effect, like similar effects in "Star Trek" and other sci-fi movies, has inadvertently created an audience that is insensitive to technology such as holography.We've seen so many shots like this in movies that it's easy to mistake this technique. In fact, Stephen Benton, the MIT professor who invented white-light holography (which is commonly used in credit cards today), spent more than two decades, using the power of a million-dollar supercomputer, It took almost priceless special optics and the tireless work of a dozen brilliant doctoral students to achieve a similar effect (to what you see in the movies). Holography (holography) was invented by Hungarian scientist Dennis Gable in 1948.In the simplest terms, a hologram is the collection of all possible views of a situation on a single plane in a light-modulated pattern.Then, when the light beam passes through or is reflected by this plane, the original scene will be optically recombined in space to become a three-dimensional image. 1 million times the resolution In the continuous improvement of display technology, holography has always been a dark horse whose strength is unpredictable and may come from behind.One reason for this is that holography requires extremely high resolution.Your TV should have 480 visible scan lines (it can be much less than that), and if your TV screen is 10 inches high, that means your TV (at its best) has about 50 scan lines.Holography requires a resolution of 5 scan lines per inch, or 1,000 times more horizontal scan lines than your TV.To make matters worse, resolution means scanning both horizontally and vertically, so holography requires 1,000 times the resolution of today's TVs, or 1 million times.One of the reasons you see holograms on credit cards and even banknotes in some countries is precisely because this kind of resolution requires very complex printing techniques that are difficult to counterfeit. Benton and his colleagues made their way to holography by cleverly identifying what the human eye and sensory system really needs and comparing it to what natural holograms can produce. .Since the human eye is the receiver of images, it would be foolish to present it with details that it cannot distinguish.In the same way, Benton noticed that we gaze at an image being formed in space (sampled from space) in the same way we gaze at a single frame in a movie (sampled in time).Slow motion images are about 30 frames per second (60 fields).Thus, rather than making a holographic image that reflects all viewpoints, it would be better to make it an image with one viewpoint per inch and omit other data in between.He succeeded. Beyond that, Benton and his colleagues noticed that our sense of space is largely a horizontal one.Because of the parallax of juxtaposed eyes, and because our eyes always move in a near-horizontal direction, horizontal parallax is much more important in our perception of space than vertical parallax (changes up and down), captured by horizontal parallax The signal in space accounts for the vast majority.It might be different if our eyes were stacked one on top of the other, or if we used to climb up and down trees.But that is not the case.In fact, horizontal parallax affected vision so much that Benton later decided not to consider vertical parallax at all. As a result, the holograms displayed by the Media Lab have almost no vertical parallax.When we showed visitors a set of holographic samples hanging outside Benton's lab, they didn't even notice that the samples were free of vertical parallax. In fact, once I told them that the images had no vertical parallax, they would bend down and stand on tiptoe to look at them repeatedly before they believed them. The result of spatial sampling combined with horizontal parallax (ignoring vertical parallax entirely) is that, in the hands of Benton's group, it now requires only: % of the computing power of a full-resolution hologram to produce this new of the image.For this reason, they produced the world's first full-color, real-time holographic images of shapes with varying shades of light and dark.It floats freely in the air and is about the size and shape of a teacup or "chunky" Princess Leia.The whole is greater than the sum of its parts and the quality of the display really isn't just about visuals.It is a viewing experience that typically employs other sensory experiences. The whole composed of various sense palaces is indeed greater than the sum of its parts. In the early days of high-definition television, social scientist Russ Newman, then working at the Media Lab, conducted a landmark experiment to test viewers' reactions to the quality of the display.He installed two identical HDTV and VCR systems, showing identical high-quality videotapes.However, in the A group he used the normal sound quality of the VCR and the small speakers of the TV, while in the Japan group he used great speakers that played better than the CD. The results were surprising.Many subjects reported that the images in the day group were much clearer.In fact, the quality of the two sets of images was identical.But the viewing experience of Group B is much better.We tend to judge sensory experience as a whole rather than in terms of individual parts of the experience.This important observation is sometimes overlooked in the design of virtual reality systems. When designing military tank trainers, a lot of care has been taken to achieve the highest display quality (almost at any cost), and the hope is that when you look at the display, it looks almost as if you were looking at it from the small window of the tank. Same as going out.It was a good idea, but after painstaking efforts to continuously increase the number of scan lines, the designer thought of introducing an inexpensive, slightly vibrating motion platform. The designer added a few more Additional sensory effects - the sound of tank motors and the sound of rolling over the ground - the overall result feels very realistic, allowing designers to reduce the number of scan lines without affecting the overall visual effect. Regardless, the system looks and feels It sounds very real and has exceeded the original requirements. People often ask me why I wear glasses when I eat, because I obviously don't need glasses to see the food and the knife and fork.My answer is simple, food looks more delicious when I wear glasses. Being able to clearly see the food is part of the quality of the meal. "Seeing" and "feeling" complement each other.