Hologram imaging technology features, advantages and disadvantages

Holography is the science of making holograms, It is a form of photography that allows the image to be recorded in three dimensions, The technique of holography can be used to optically store, retrieve, and process the information, The hologram is the photographic recording of the light field, rather than of the image formed by the lens.

Holography

Holography requires the use of laser light to illuminate the subject and to view the finished hologram, The hologram is used to display a fully three-dimensional image of the holographic subject, that is seen without the aid of special glasses or other intermediate optics.

The hologram is not an image, It is unintelligible when viewed under diffuse ambient light, It is an encoding of the light field as an interference pattern of random variations in the opacity, density, or surface profile of the photographic medium.

If suitably lit, The interference pattern can diffract the light into the reproduction of the original light field & the objects that were in it appear to be there, exhibiting visual depth cues such as parallax & perspective which change realistically with any change in the relative position of the observer.

Holography is distinct from lenticular & the other earlier autostereoscopic 3D display technologies, that can produce superficially similar results but are based on conventional lens imaging, Stage illusions such as Pepper’s Ghost and the other unusual, baffling, or seemingly magical images are incorrectly called the holograms.

Holography was developed by D. Gabor in 1947, He recognized that when a suitable coherent reference wave is present simultaneously with the light scattered from the 3D object, then the information about the amplitude and phase of the scattered waves can be recorded.

Although recording media responds only to light intensity, He demonstrated that, from such the recorded interference pattern, which he called the hologram, the total recording, an image of the original 3D object can ultimately be obtained.

Although, recording the hologram of the real object requires some wave interference between two laser beams with a high degree of coherence between them in a dark room, So, this system must be kept very stable since a very slight movement can destroy the interference fringes, in which both intensity and phase information of the 3D object are contained.

These requirements, together with the development and printing processes, have prevented conventional holography from becoming widely employed in the field, As the solution for these limitations of conventional holography, The computer-generated hologram (CGH) has been suggested.

Compared to the conventional holographic approaches, CGH does not rely on the availability of specialized holographic recording materials and it can synthesize the optical wave-fronts without having to record the physical manifestation of them, and it offers unprecedented wave-front control by making it easy to store, manipulate, transmit and replicate the holographic data.

Although CGH-based display systems can be built today, their high cost makes them impractical for many applications, However, as the computer and optical hardware costs decrease, CGH displays will become a viable alternative soon.

Hologram label printing is a new type of anti-counterfeiting technology that applies laser holographic technology, This technology is known as laser holographic anti-counterfeiting technology, Nowadays, with the progress and development of other anti-counterfeiting technologies, holographic anti-counterfeiting technologies have had new developments and applications.

Holograms can be entirely computer-generated to show objects or scenes that never existed, Holography is used in many aspects of industrial nondestructive testing, ultrasonic holography, holographic microscopy, holographic memory, holographic film, and television.

Holography advantages

Production for the source of the holographic products would spend a lot of time and money for the manufacturer, but the cost of bulk and large amount copy for the holographic products such as the holographic stickers would become relatively cheap, This should be the main reason why the enterprises for the production of consumption goods want to select this kind of anti-imitation technology.

It would be very difficult for people to get the equipment and technical details for the hologram stickers volume production, Today, Purchasing and getting this traditional equipment has become very easy but the manufacturers of this equipment try their best to enhance the quality & security level of their products that can help them to avoid the adverse copying.

When people have a closer look at these hologram stickers, holographic printing finds that the holographic products such as the stickers and the labels are very different from the traditional trademarks of the commodities, The forged tools such as the cameras and the printers which the forger uses have no effect for holographic copying.

Holography not only records the reflective intensity on the object but also the phase information, So, even if the hologram picture is left with only a small part, It still reproduces all the scenery, It will be very convenient for museums, libraries, and other collections of pictures.

Since the holographic technology is capable of recording all of the information of the object itself, the storage capacity is large enough, So, as the carrier of the storage, the holographic storage technology can be applied to the documentation of libraries, schools, and the other institutions to save.

You can have holographic imaging technology without wearing special polarized glasses, not only the audience to bring convenience, but it reduces the cost of the traditional 3D display, The real-time electronic holographic (holo video) display can create a truly 3-D computer graphics image with all of the depth cues ( motion parallax, ocular accommodation, occlusion, etc.) and resolution sufficient to offer the extreme realism.

Holovideo displays promise to enhance numerous applications in the creation and manipulation of information, including telepresence, education, medical imaging, interactive design, and scientific visualization.

Electro holographic display generates a 3-D holographic image from a 3-D description of a scene, This process involves many steps, grouped into two main processes which are Computer graphics and Fringe computation.

Computer graphics: by using a camera, a sequence of images is generated, Fringe computation: A 3-D description scene is converted into the holographic fringe using an interference or diffraction approach, Optical modulation, where the light is modulated by the fringe using SLM and optical lens.

Holographic technology can supply high-quality images and accurate depth cues viewed by the human eyes without any special observation devices, So, Holographic 3D display is one of the attractive approaches for creating the most authentic illusion for observing volumetric 3D objects.

3D Holographic display considerations are Large bandwidth, High transmission rate, Design considerations like alignment and packaging issues, Holographic bandwidth compression and faster digital hardware allow computation at interactive rates and promise to continue to increase the speed of displayed holo video images.

The alignment & packaging of the optical lens and the spatial light modulator is a great problem that can be removed using Infosys MHOE Technology, Micro holographic optical elements (MHOEs) are used for displaying the holographic three-dimensional image of the object (e.g., received by the device in the form of a computer-generated hologram via a communication network).

Devices for displaying the holographic three-dimensional images of the objects contain the laser source, the spatial filter using a micro holographic optical element (MHOE) lens, a collimating MHOE lens, a spatial light modulator, and cylindrical MHOE lenses.

Computer-generated holograms can be created, sent, received and displayed using the technology, They have multiple function capability and wavelength selectivity, They offer design flexibility & ease of replication, No alignment and packaging issues, and Rigid and stress-resistant setup.

Holography disadvantages

Most holographic products such as holographic stickers had already been decorated with reliefs which would let the machine copying become relatively easy and cheap, so, It would be hard for the people to put a coherent distinction between the holographic products & the source products.

Conventional Holography OR Conventional optical elements record holograms of the real object using some wave interference between two laser beams with a high degree of coherence between them in a dark room.

The system must be kept very stable since even a very slight movement can destroy the interference fringes, in which both intensity and phase information of the 3D object are contained, The device will be heavy and will have alignment and packaging issues.

Computer-generated holography (e.g., using computer-generated holograms) can be used to convert 3D information to 2D for sending and receiving using existing communication networks, High cost makes them impractical for many applications, There are packaging and alignment issues, It is difficult to implement in smaller displays.

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