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Applications of Computational Holographic Imaging(CHI)

           Applications of Computational Holographic Imaging


While  going  through some quotes on the internet , I came across one quote  which I would like to share with you all ...
           Life is a hologram. Even the smallest moment contains eternity within it.
                                                                                                       -Banani Ray 
 This relates the concept of hologram to our life in very philosophical way...like this there are many applications of holograms in industrial sector and our life
As we know that the holography uses the concept of interference, we can have many applications  of it in the different sectors .since holography is a two-stage process of photography using  light from a laser  where,in the first stage a hologram is formed by combining the light scattered from the object and the direct laser beam on a photographic plate and then three- dimensional image is reconstructed by directing the laser beam through the hologram.         The total process used in above paragraph can result in many applications such as information storage, image recording in depth, the use of holograms as optical elements, precise interferometric measurements on three-dimensional objects. Now-a-days there are many uses of holography  in scientific research, engineering and medical assessment.

                              
    Doctor making use of holographic imaging to analyse part of bones(Image source-medgadget.com)
  • To prepare the samples in medical assessment and to view the images of the specimans clearly, X-ray holography is used widely where X-ray holography is a type of coherent diffractive imaging where the phase information is encoded in the diffraction pattern by means of interference with a reference beam and the image of the specimen is obtained by a single Fourier transform of the interference pattern.
                                Laser light shows X-ray holographic images of viruses
             Analysis of virus using X-ray holographic Imaging(Image source:healthcare-in-europe.com)
  • For non destructive imaging without contact with high resolution inside cavities of internal organs, Endoscopic holography is used. Endoscopic holography combines the concepts from holography and endoscopy.Endoscopic holography has ability to  record 3-D large focal depth and high resolution images of tissues.
             
  • Holographic stereogram,conical stereogram and multiplex hologram are used to synthesize the three dimensional  images of biological specimans. Multiplex holography uses the scaled images of the objects making the hologram.
  • Holograms provide way to store the toothprints in dentistry where tooth prints are the records for forensic purpose.
  • Holographic contouring technique is used to study the topography of teeth.
  • In semiconductor industry electron holography is used to create images from materials at atomic dimensions and study changes in fields of nanostructured materials, DRAM capacitor design and high temperature superconductors. 
                               What Exactly Are Holograms?

                          Future use of holographic imaging(Image source :iqsdirectory.com)

         So we can have more applications like above in future which may help us in  field of education,IT industry etc. Really holographic imaging has simplified our life to the great extent.
                                                                                  
                                                               Thank you!!


                                                                                                    -Hrishikesh Adsod














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Background

    image source:iStock The concept of hologram/holography originated in Hungary when one of the resident scientists there invented it as a method to improve the resolution of electron microscopes .         Holography is composed of following main processes:         1. Calculations for   the scattered wavefronts originating from the object.         2. Encoding the data for display purpose.         3. Visual reconstruction from   the interference pattern onto a coherent beam of light by using some technologies and transport it to the user  who is going to observe the hologram.         Now that we're done with a brief intro to this topic we shall be looking further deep into what goes inside to develop such fascinating or 'real life-like'  technology. Do visit our next blog for more such information! 

Early Developments

The first holograms were invented by A. Lohmann . It made use of computer line printers and prodcued using coherent LASER illumination .Th following figure shows one of the first computer-generated hologram and its reconstruction.   As one can observe easily, it is very hard to comprehend the actual image from the holograms. As the developments progressed , more and more sophisticated recording devices were used to create gray scale holograms. The figure represents an example of grey-scale computer-generated hologram and an image reconstructed from a grey scale hologram. Implementation approach by the inventors : The grey scale holograms were recorded using electro-mechanical recording device (a modified faximile machine) with resolution 200 μm and then optically reduced with reduction factor 20 to final resolution 10 μm for optical reconstruction with a laser beam. Now we'll discuss about the mathematical aspects .Mathematical model of the object is usedto