entranceHow to make a hologram on your phone. A hologram on a smartphone
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You can turn your smartphone into a holographic 3-D player thanks to a simple project that a user named Mrwhosetheboss showed in his video.
This user has created a special device that, in conjunction with a video sequence created specifically for the hologram, creates the illusion of a 3-D picture floating in the air.
You will need:
Old disk case
Sharp knife
Some duct tape (scotch tape)
Ruler
Squared paper.
1. Draw 3 trapezoids on paper, measuring 1 cm x 3.5 cm x 6 cm.
2. Cut out the trapezoid.
3. Take a case for discs, carefully remove the sides, circle 4 times the trapezoid cut from paper.
4. Using a utility knife, cut out 4 trapezoids.
5. Glue all the trapezoids together to form a part of the pyramid.
6. Download demo video to your smartphone and use this design to view the hologram.
Here are some video clips that can be used for this technology:
How to make a hologram
Holographic video
Video clips that are used for this fixture, play the same picture from four sides.
When all these four video series reflected in the panels of the created device, you get the illusion of a 3-D hologram.
Holographic effect
Unfortunately, this illusion cannot be called a hologram, since here 2-D pictures and videos are used to create the desired effect.
A true hologram creates a 3-D image and uses laser beam separation technology.
We make a simple device for viewing 3D holograms on your smartphone or tablet. Ever wanted to watch a video or watch pictures in 3D without glasses? In this tutorial, you will learn how to make a very simple 3D hologram viewer on your smartphone or tablet. All you need to do this is five minutes of your time. And yes, today we don't need Arduino, Raspberry and other boards.
For our device, we need a simple set of components:
- Clear acrylic / plastic sheet 0.5mm (you can use the plastic sheets used in packaging)
- Access to the printer (if possible)
- Scissors
- Cutting blade
- Transparent tape
- Ruler
- Pencil pen
- Smartphone
How does the 3D pyramid hologram work?
A holographic pyramid is a simple device that can be made by creating a pyramid shape with a cropped top from a sheet of plastic. The device creates a three-dimensional illusion for the viewer and makes the image or video appear as if it were in the air. Works on the principle of Pepper's Ghost (English Wikipedia). Four symmetrically opposite versions of the same image are projected onto the four faces of the pyramid. Basically, each side projects an image falling on it into the center of the pyramid. These projections work in unison to form a whole figure that creates a three-dimensional illusion.
How to create a pyramid for 3D holograms
1. Print the template shown below on a sheet of A4 paper.
NOTE... If you don't have access to a printer, you can also create a template yourself. Draw a basic "trapezoid" on a piece of paper using the dimensions in the picture above. Parallel sides = 1 cm and 6 cm, the other two sides are 4.5 cm each. You can always double or triple the dimensions proportionally for use on a large display.
2. Trace the shape on the plastic sheet using a ruler and pen. For the trapezoidal pattern, mark four similar paths on the plastic sheet. Now carefully cut out the outlines with a cutting blade and a ruler. Try to make your cuts as precise as possible to create a more perfect pyramid.
3. If you used the print template: very lightly cut the red edges with the cutting blade. This will allow you to better fold the edges and form a pyramid shape. Glue the exposed edges of the sheet together using transparent tape.
If you used a trapezoidal pattern: join the four edges to form a pyramid shape. Connect them. Either way, you end up with a pyramid like the one shown below.
4. That's it! You've made yourself a pyramid for future holograms! All you have to do now is play the hologram on your phone. Place the hologram in the center of the screen as shown in the image below and enjoy the show. Remember to turn off the lights in the room before starting video playback.
5. Now the most important thing! Many holograms can be found on Youtube... You can see what can happen in the video below.
In terms of developing fine motor skills of hands, and at the same time skills of working with various materials, I conducted a small home master class on creating simple holograms using a mobile phone or tablet and transparent polycarbonate. On the net, I found two options for creating holograms, but both of them use the same principles for obtaining a three-dimensional optical illusion. It is possible that if you dig deep enough, you can find more options. Therefore, if suddenly you managed to google more ways to create a simple hologram using a smartphone screen, then feel free to unsubscribe in the comments with the appropriate links.
So, both options use the features of optics, namely the refraction of light rays when passing between media with different optical density, but optics will beat me with sticks for amateurish terms, but I will continue. The bottom line is that when a beam of light passes from the screen of a mobile phone, tablet, monitor display or TV in general through the border of air and transparent polycarbonate, partial reflection of light occurs. It is thanks to this reflection that the effect of a holographic, i.e. completely volumetric, image is created. Based on this, you can figure out that transparent polycarbonate is needed to create a hologram. Where can I get it?
V modern world An excellent source of polycarbonate can be regular CD boxes, which can be irrevocably borrowed from your home audio library or simply bought from a computer or stock store. These stores usually sell recordable CDs or DVDs in "spindle-mounted" packaging. And at the same time, in order to earn some more money, stores sell separate boxes for them. It is best to use transparent, unpainted boxes, so as not to lose the precious brightness of the screen, while the image will be the best possible.
Option 1. Holho - pyramidal hologram
For the pyramidal hologram, they even came up with a special name Holho. The essence of this technique is in broadcasting four images at once on a slightly truncated pyramid, placed "on the bottom", that is, with the top down, on the smartphone screen. When playing a specially prepared video on the phone screen, the image is reflected from the edges of the pyramid and a complete illusion of an object floating in the air is created. The essence of the pyramidal hologram is that each of the images is projected onto its own edge, and when viewing, the observer sees all four images at once, combined into a single three-dimensional picture by the pyramid's edges.
The pyramid is assembled simply, you do not need to graduate from Felix Kirsanov's oratory courses and the Higher School of Economics in order to cut the required blanks from the lid of the disc box. Only four of them are needed, and they are cut according to the template, kindly prepared by me.
The cutting template itself is available here. When printing, you must accurately select the paper size and enable printing at the actual size.
Cutting out the polycarbonate is easy if you place the printed template under the lid, and then make deep cuts along the lines with a sharp wallpaper knife. The cut made in this way then easily allows you to break off the unnecessary section of the cover. Only the cut needs to be made over the entire width of the cover, otherwise there will be no breakage. The cut pieces can be glued together with super glue or simply secured with Scotch tape.
| One of the demo videos. |
To get the hologram effect, you need to move into a room with dim light, install a pyramid on the smartphone screen, point down, center it according to the marks on the video. And in principle, that's all, you can enjoy watching wonderful examples of "home magic".
| And one more demo video. |
A fair amount of uploaded to YouTube demonstration videos under Holho, so you can safely pick up even something completely unusual. Moreover, there are already industrially manufactured and nice looking Holho pyramid converters. And remember that not only the screen of a phone or tablet, but also any other source can act as a source of video for a hologram, here it is important to compare the size of the pyramid and the screen.
Option 2. Frontal linear hologram
As an alternative to Holho, a linear hologram can be mentioned, which is created by projecting an image onto successively installed reflectors. If a pyramidal hologram looks like a hologram from any side, then a linear one allows you to enjoy an unreal effect from only one side, from the front. The essence of a device for reproducing a linear hologram is almost the same as that of a pyramidal hologram, but here the image is transmitted to several, usually three, mini screens made of transparent polycarbonate. The screens are installed at an angle of 45 degrees and one after another. The screens themselves vary in height, which adds even more realism to the resulting image.
For the manufacture of the device, the same boxes from CDs are ideal, only here they are completely used, for which special thanks to the author of the device. You can cut the box using the technique used to build the pyramidal device, only you will have to measure the dimensions of the screens yourself. And for fixing parts of the device, thermal glue is used, not sticky tape. But if you have at least minimally straight hands, everything works out the first time. While assembling, hold the shields a little until the glue is completely solidified.
To reproduce the hologram, you need to place the linear hologram device on the screen of a tablet or larger device. By the way, both linear and pyramidal holograms can be used as in original video and upside down. This does not change the effect, although the video may turn upside down.
If we compare both devices, then I like the Holho version more, because it allows you to create a hologram without any restrictions on the number of scene plans. In the linear version, only a few levels of volume are available to the user, equal to the number of installed polycarbonate screens. With three screens - correspondingly three levels of scene depth.
In other words, if the Holho version creates a truly three-dimensional image floating in the air, then the front linear hologram version looks more like the effect of 3D television on a flat screen. Although, of course, both options look good and they should be assembled both, since nothing extraordinary is required to create such a toy, and it will hardly take more than an hour to assemble two devices at once.
The very news about RED and smartphones discouraged many ordinary people: “Seriously? They make cameras - what other smartphones ... "But even more unexpected was the announcement that the smartphone will support holograms!
Many decided that the guys were crazy, or it was some kind of deception of the century, a strange PR or ...
Is it really possible? Maybe a lightsaber is just around the corner?
- Yes it is possible.
But not as Hollywood draws us - we will not see the projection of Princess Leia. Most likely, you just do not know what a hologram is because you watched a lot of science fiction instead of studying physics. Just for such people, this article was written - just about the complex.
Holography vs Photography
- What are holograms? Let's see Wikipedia ...Holography - a set of technologies for accurate recording, reproduction and reshaping of wave fields of optical electromagnetic radiation, a special photographic method in which images of three-dimensional objects, which are highly similar to real ones, are registered with the help of a laser and then restored.
Most likely, the understanding did not increase - it is better to watch the video
If it seemed to you that these were mirrors and jars from forfeits behind glass - review again.
These are real holograms. No trickery - just science.
How it works?
First, let's answer the question - how do we perceive volume in general? This is possible due to the fact that we have two eyes - each sees an object from different angles.
The brain processes these two slightly different pictures and builds one volumetric model in our minds. Thanks to this, we can estimate the distance to objects just by looking at them - the brain automatically estimates the tension of the eye muscles and determines the distance with fairly high accuracy.
The eye as an optical device
The camera works on the same principles as human eye- therefore, consider the eye as an optical device.
The eye reacts to light, and light, as you know, is electromagnetic wave, exactly the same as, for example, Wi-Fi - only higher frequency.
In order for the eye to see something - light must come to it from this point, when we see some object - we register the object reflected by this object in all directions light that reflects in all directions every point of the surface
Every point on the surface reflects light in all directions!
This is an extremely important principle that needs to be understood - a whole mishmash of different waves in different directions passes through each piece of space, but we see only what enters our eye through the pupil.Of all the jumble of waves, only a small piece of the wave gets into the eye / camera, which has slipped through the pupil.
When we turn our head to see an object from the side, pieces of waves reflected from this object begin to fall into our eye.
These waves have always been here, they are simply invisible to the eye until they go into it from the front.
The camera / movie camera works according to the same principle - from the whole variety of waves passing in all directions through space - only the part that goes in one direction is fixed- so the photos look flat - it's just a small part of the original information
Holography
Now we can finally move on to the principle of creation volumetric shots, consider the part of the space, circled in purple, imagine that we put glass in front of the object.
If we could somehow freeze / remember the picture of the waves passing through this glass, and then reproduce exactly all amplitudes, frequencies and phases- then we would not save a small green piece from the wave, which carries information only about one direction, but a whole picture of all waves, which contains information about all possible viewing angles.
If you don't see the difference ...
If the glass comes out exactly the same picture of the waves that the object was emitting at the moment "Sealing" this picture - it will be visually impossible to distinguish such "Photograph" from a real object, and the object will be visible from all angles as the whole picture of waves passing through space is restored
The camera sees only in one direction - so in order to capture the entire wave front, we need to take pictures in all directions, and then combine them into one volumetric picture - this is the principle of 3D scanning.
This method of shooting 3D objects is similar to FDM 3D printing with plastic, which is actually printed in 2D many times - at a qualitative level, this is "Crutch"
Implementation
The matter is small - all that remains is to figure out how to seal in space all the radio waves that pass through it, and then restore, here I probably won't go into technical details - the main thing is to understand the basic principle. (If there is interest - there is an opportunity to shoot a hologram in the spectroscopy laboratory, there are many nuances - so this is a topic for the next article).Stop the light
The problem is that waves are in constant motion... And if we want to fix a picture in space, we must react with some kind of photosensitive material for some time and the printed the picture must be motionless at this time.Taking a regular photograph - we do not stop the light, we cut out a narrow direction along which we expose the matrix with rays with constant amplitude, each of which connects the point of the object and the pixel on the matrix.
Standing waves
We want to capture all directions at once and we don't have Agamoto's eyes to freeze time - you have to think with your head.
It's good that this has already been done back in 1947 Denesh Gabor(one thousand nine hundred and forty-seven, Karl!). For which he received the Nobel Prize.
The bottom line is the following - if you add two waves with the same frequency and different directions, then at the intersection of the highs and lows of these waves will appear standing wave- a virtual wave (since light waves do not act on each other), which is the sum of two traveling waves of the same frequency. Due to this, it is possible to illuminate a stationary picture from the intersections of two waves in a photographic plate.
By illuminating one plate with three colors of the reference waves - red, blue and green - we get a full-color hologram, indistinguishable from the original.
If you now remove the object and shine a reference wave on the plate, an exact copy of the waves that the scanned object created will come out of the plate.
Technological requirements
Since it is very important that the frequencies of the object and reference waves are the same - an incredibly stable light source is needed for the standing wave to remain stationary - with a slight difference in frequencies, the wave will begin to move and the hologram will be smeared.
Green light
Such a source exists - it is called laser... Before the invention of the laser in 1960, holography had no commercial development; gas-discharge lamps were used for recording.The world's first was invented in 2009 semiconductor green laser(red and blue were already there). Prior to this, green lasers used frequency doubling of an infrared laser diode passed through a frequency doubling nonlinear optical crystal. However, this design has an extremely low efficiency, high cost, complexity, etc.
Invention semiconductor green laser gave the green light to the development of miniature RGB laser projectors... 9 years have passed already - quite a sufficient time for the transition of technology to industrial use - and now we are beginning to observe the most active market participants, soon there will be even more cool and interesting products
Resolution
The resolution of the recording plate should be incredibly high - after all, the distance between the illuminated nodes of the standing wave is comparable to the wavelength of light, which is ~ 600nm! That is, the resolution is at least 1666 mm ^ -1.If, when photographing, each point of the matrix corresponds to a point on the object, then in a hologram, light falls on each point of the matrix from all points object, that is, each part of the hologram contains information about the entire object.
Conclusions:
- The principle of holography was invented half a century ago, but it was not possible to implement it at a good level due to the lack of technology - in particular, lasers, recording materials
- Even using ordinary plates - creating a hologram is a rather subtle and painstaking process - making a holographic full-color scanner and a digitally controlled holographic screen in a smartphone is a very strong challenge.
- Even the ability to make one static hologram from a tripod (not to mention recording a hologram "by hand") and display it on a revolutionary holographic display in the form factor of a smartphone will already be an achievement that will change entire industries.
UPD: thanks for the comment
Relatively recently there was an article about cameras and light field displays, it seems that RED is preparing its new product on this basis.