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Thread: hand drawn hologram

  1. #11
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    ... what's the "limit" to coarser line widths? - as already said, 30 microns with fiberlasers in galvoscanner heads is common, 10 microns with beam-expander or smaller factor f-theta optics no problem.

    Were there some samples of computer generated "fringe-holograms" or scanned scratch holograms? - or has someone some nice ones to scan?

    Viktor
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  2. #12
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    I have not looked for computer generated. That’s what I’m thinking. Write the code to take a vector drawing to hologram. Everything I saw was by hand. The star wars thing was prob computer but they aren’t likely to share that code.

    https://www.media.mit.edu/projects/d...rams/overview/

  3. #13
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    I have the code, and there is a version on a website that you just upload the picture and it sends you the FFTed image.

    Steve
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  4. #14
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    Hi Steve,

    can you send me the code and the link to the generator?

    Viktor
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  5. #15
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    Post the code. Wonder if it can do color some way.

  6. #16
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    I was completely unaware of the existence of scratch-holograms. This is really interesting!

    So how wide would the scratches be from the point of a compass needle as described in the first post? I would imagine they would be quite a bit wider than 30 microns at least.?.

    If so, then a laser etcher should be able to create fine-enough cuts for images of similar fidelity to the scratch holograms in the first post. Probably much finer, even. The only question would be whether or not the inside surface of the engraved cuts would have the same reflective properties as an actual scratch...

    As for the math, I would think this would be fairly straightforward as the equation for a circle is a given. For each point in the image, simply draw an arc of some arbitrary number of degrees at a radius "R" distance from the X,Y coordinates of the point in the source image. The radius "R" of the scratch determines the separation between left and right (and thus the "Z" axis for a given point).

    Damn, this is cool... Thinking we should try this at SELEM!

    Adam

  7. #17
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    From the first link in the first post above:

    "No one seems to realize that the well-known "Rainbow Hologram" technique can also let you produce holograms which are not based on optical interference at all. This makes it possible for you to create holograms where the "interference fringes" are so large that they are easily seen by the naked eye; where they are more like the grooves of an LP record than like the patterns on a CDROM."

    Totally not true. the author is confusing the embossing technique for mass producing holograms with the Rainbow technique for making transmission holograms white-light viewable. Rainbow holograms are typically embossed. Neither makes fringes "easily seen by the naked eye".

    Just reviewed the paper linked second in the OP. The author certainly does not understand the basics of holography. One can not arbitrarily change fringe spacing to make a larger hologram! He pulled a drawing out of a paper, then misinterprets what it shows.

    Last edited by Eidetic; 06-24-2019 at 07:37.

  8. #18
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    Quote Originally Posted by buffo View Post
    I was completely unaware of the existence of scratch-holograms. This is really interesting!

    So how wide would the scratches be from the point of a compass needle as described in the first post? I would imagine they would be quite a bit wider than 30 microns at least.?.

    If so, then a laser etcher should be able to create fine-enough cuts for images of similar fidelity to the scratch holograms in the first post. Probably much finer, even. The only question would be whether or not the inside surface of the engraved cuts would have the same reflective properties as an actual scratch...

    As for the math, I would think this would be fairly straightforward as the equation for a circle is a given. For each point in the image, simply draw an arc of some arbitrary number of degrees at a radius "R" distance from the X,Y coordinates of the point in the source image. The radius "R" of the scratch determines the separation between left and right (and thus the "Z" axis for a given point).

    Damn, this is cool... Thinking we should try this at SELEM!

    Adam
    See if it can be made into the t-shirt design.

  9. #19
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    Doubt the embroidery on the shirts would be accurate enough! But it's a fun idea in the abstract.

    Adam

  10. #20
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