3D world

3D world

Nowadays, all 3D games have become popular. There are various games from AR games to VR games. The technology that is spreading in games is now in the process of linking it to the real world to make it more convenient. I would like to introduce an article about AR and holograms, which are the core of 3D.



Do you know the difference between 3D holograms and AR (Augmented Reality)?

In recent years, various technological innovations have progressed in the world of video.
Among them, the representative ones are "3D hologram" and "AR (augmented reality)".
The two video technologies are completely different, but some may not be able to tell which one is what.

Therefore, this time, I will explain the difference between the two while introducing the features of 3D hologram and AR respectively.
Let's understand what 3D holograms and AR are like.



■ What is AR?

First of all, I will introduce what kind of technology AR is.
AR is an abbreviation for Augmented Reality, and when converted to Japanese, it becomes augmented reality.
Many people may not understand what augmented reality is, but simply put, technology that expands visual information by capturing information that does not exist in the real world, converting it into data, and outputting it as information. Point to.

For example, even if there is nothing on the desk in the real world, it is possible to display objects and letters on the desk that should be empty by giving AR technology.
By using AR to add other information to the real world, we will "extend" a lot of information to the real world.

■ How AR works
AR basically places an "AR marker" that determines where information is displayed in the real world, so that the camera recognizes the position of the marker, reads the information, and adds an image.
The most adopted AR marker is the QR code.
However, the QR code also has the disadvantage that it takes time to place it.

Markerless AR solves this problem. Markerless AR is to add information added by location information even if there is no marker.
For example, GPS and sensors related to acceleration and tilt are used to determine where to display information.

■ Various types of AR
As shown above, there are various types of AR, such as those that use AR markers and those that can display information without markers.
So, let's introduce what kind of AR is, along with how it is used.

■ AR marker type
As I introduced earlier, the AR marker type is a type that decides where to display information by placing a marker in the real world.
The advantage of the AR marker is that it is easy to make a product or novelty because you can see the AR image by combining the item called AR card and the application for reading the information of the AR card.

For example, a candy toy that had an AR marker as a bonus was sold before, and when you look at the AR marker using the app, you can feel that an anime character is in the real world.
In addition, Nintendo's portable game machine 3DS also sold AR markers and was able to make game characters appear by passing through the camera equipped in 3DS, and it was possible to actually operate and play the game. ..
In the case of the AR marker type, it cannot be used without using the AR marker, so it has the disadvantage that it is necessary to prepare an AR marker, but the fact that it is easy to commercialize is a big attraction for companies. Is it not?

■ GPS type
It utilizes GPS and is currently the most adopted type of AR-based application.
We will acquire location information with GPS and use that location information to incorporate new information into the real world.

For example, the app called "Sekai Camera", which has been a hot topic in the past, was a new SNS app that allows you to associate and save the posted content with GPS location information, and you can see many comments in the city.
You can see what other people are commenting on the place using the same app.
Furthermore, "Pokemon GO", which is still popular all over the world, is a reality of the game world view that Pokemon can appear and items can be obtained by actually walking in the real world or going to a certain place. It is an app that you can enjoy in the world.

Since most smartphones are basically equipped with GPS type as standard equipment, it is easy to develop and there is no need to make a marker as an actual marker like AR marker, so there is an advantage that cost can be suppressed.
However, if GPS cannot be used, AR cannot be seen, so AR cannot be seen where GPS radio waves do not reach, and there is a high possibility that an error will occur due to GPS performance. I will.

■ IoT type
The IoT type is an AR that utilizes the "Internet of Things" and refers to a technology that enables communication by connecting a personal computer or smartphone to the Internet.
I think you know that AR can extend information to the real world, but that doesn't mean that you can use that information in real life.
It just displays the information in that location, so the AR doesn't actually do anything.

However, by combining IoT, various things can be done.
For example, it does useful things in real life, such as opening and closing keys, turning on electricity, and turning on the bath.
Although these are basically IoT technologies, it can be said that AR and IoT are compatible because the virtual characters projected by AR seem to be actually working.

■ What is a 3D hologram?
Next, let's introduce what a 3D hologram is like.
3D hologram refers to a technology that can record images in three dimensions.

When taking a picture, the digital camera can read the information in front of you in a plane and convert it into data, then print it into a picture, or you can see only the data.
However, since only flat data can be recorded, it is not possible to grasp what is behind what is being photographed or what shape it has.

In the case of 3D holograms, in addition to the "amplitude of light" and "wavelength" that can be saved as photographs and videos, the "phase" can be recorded.
The phase shows where the light is coming from, and a reference light is needed to record this phase.
When the reference light and the light for recording an object / person for recording are combined, a pattern called "interference fringes" is created, and by shining the same reference light as when recording the object / person on the pattern, it is three-dimensional. Information can be projected.



■ 3D hologram that is easily mistaken
The following two points apply to 3D holograms, which are different from ordinary photographs and videos.

・ Phase information can be recorded
・ Photos and videos can be reproduced by shining the same reference light as when recording.
If these two points do not apply, it cannot be basically called a 3D hologram, but like a 3D hologram, a stereoscopic image can be seen floating in the air, or the image can be seen at the same time without a head-mounted display. Many people call it a 3D hologram.
A technology that is similar to a 3D hologram but has a different mechanism is called a "pseudo-hologram".

Pseudo-holograms are just like 3D holograms, not exactly the same mechanism.
However, since it is possible to project an image that is quite close to a 3D hologram, it is often mistaken for the 3D hologram itself.
There are several types of this pseudo-hologram, so let's introduce them as well.

■ Pepper's Ghost Type
Pepper's ghost is one of the visual tricks that is also used in magic tricks and is historically a fairly old technique.
For example, when you want to make an image appear on the stage, create a separate room other than on the stage, and prepare flat glass and a light source there.

While shining light on the object or person you want to project, when the light is reflected on the flat glass, it is projected to the audience seats, and the object or person who should be in a separate room can be projected as if they were on the stage.
The technique called Pepper's Ghost can be widely used even in modern times, such as being used in Hatsune Miku concerts and being used in other live music.

■ Transparent screen type
Strictly speaking, the transmissive screen type is neither a hologram nor a 3D image because the image is projected on a highly transparent screen that cannot be known unless it is actually present or close to it.
However, the transmissive screen type is currently the most popular technology among the pseudo-hologram types.

The reason why the transparent screen type is so popular is that people who are watching by using a highly transparent screen do not move the image on the screen, but actually move it in the real world. Because it can cause an optical illusion, it is possible to show high quality products, and it is also easy to use.
For example, the size of the transmissive screen can be changed for each site, or a wider range of expressions can be created by changing the projector.
In addition to using a highly transparent screen for the transparent screen type, you can inject mist and project an image on it.

Since you only produce video, you can basically finish the development in a short period of time, and because you can keep costs down, you can spend that amount on video advertisement production to improve the quality.
The disadvantage is that it is difficult to see the image from all directions like a 3D hologram, and the viewing angle is narrowed.
In that case, for example, when using a transparent screen on a stage or concert, some seats may be difficult to see depending on the audience seats.

■ Retina irradiation type
The retinal irradiation type, which has completely different properties from the above two types, can project a 3D hologram image to the human eye by irradiating the retina of a human with the image as it is, rather than projecting the image in the real world. I can do it.
Originally, when viewing 3D hologram images, the angle and reflection of light were important points, but with the retinal irradiation type, the image is projected directly to the eyes, so the image is not affected by the surrounding environment. You can see.

However, the disadvantage is that it is necessary to project an image on the retina, so a terminal or tool for irradiating the image on the retina is required.
If you don't wear this, you won't be able to see the video.
It can be said that it is not suitable for live venues that welcome a large number of fans when it comes to wearing it on each person.

■ Research combining 3D holograms and AR
Currently, technological innovations are underway for 3D holograms and AR, but in fact, research that combines 3D holograms and AR technology has begun.
What is the research that combines 3D hologram and AR? It is to make hologram technology visible on AR headsets.