Colograms – A simple way to create stereoscopic images

Dragon

Bill Beaty says “The author is making his own version of those 3D advertising signs popular in the late 1980s. (I saw many of these mounted on the walls of corridors at large airports.) They’re “lenticular” 3D which uses pinhole optics rather than cylinder lenses.” Link.

30 thoughts on “Colograms – A simple way to create stereoscopic images

  1. I think it’s time to try this with an LCD monitor to view 3D video. Does anyone know where to find some 3D video content to try?

  2. It probably already has some other name other than “colorgram.” IIR, the company who was making them in 1988 was founded by students from University of ?Indiana?

    “Lenticular” uses an array of lenses, but this method does not. When building a pinhole camera, would you call the pinhole by the name “lens?”

    It’s not a lenticular display …so it must be “slot-ticular?”

    :)

  3. The proper term is “parallax barrier display” and it is an old trick (the sharp LCD 3d displays use a variant).

    This is very neat implementation in that it uses the same printer to generate the mask and the image allowing for reasonably good registration. Registration is always the tricky part with lenticular and parallax barrier techniques.

    be sure to have a bright light table as well in that this method blocks a lot of the light (at a minimum 60%)

    With LCDs the situation is tricky in that each pixel is split into three sub-pixels (red, green and blue) which can cause color shifting. But use of a thinner tilted mask coupled with a interspersing color channels allows for up to nine seperate images to be implemented.

  4. One other thing, the free visualization toolkit (VTK) has native support for this sort of display just set the render window to StereoRenderOn() and SetStereoTypeToDresden() (based on the old ELSA/University of Dresden displays)and any VTK application will generate an appropriate image (use the vtkWindowToImageFilter to capture the resulting image)

    You can get VTK from:
    http://www.vtk.org/

    The excellent EnThought Python distribution also incorporates VTK:
    http://code.enthought.com/enthon/

  5. aolshove
    The image consists of three perspectives split into interspersed stripes (like feeding the three perspectives through a shredder and pasting them together cycling through one stripe from each photo). To view the image you use a striped mask offset from the image by ~2mm.
    For more info RTFA

  6. [i]I’m confused. This doesn’t look 3D at all to me. So, how is it supposed to be viewed?[/i]

    That image must be placed behind a black slot-mask. Or it could be placed behind an array of cylinder lenses, as with those three-D religious postcards.

    The image on Make Blog contains all the 3D information in the form of multiple viewpoints compressed into narrow vertical swaths of pixels

  7. I’ve seen parallax barrier/lenticular kits that you can buy in computer stores in Thailand. It had some software (simple image manipulation, 3D title maker, and the lenticular program) along with a picture frame that had a screen of the ridged lenticular material. The whole thing looked very cool. I think it was being sold by a printer maker, but I can’t remember what one. I do a bit of stereo photography here and there and was quite intrigued with it, but sadly not enough to buy the kit. The free software in the DIY article should be fun to play with though.

  8. [QOUTE] IIR, the company who was making them in 1988 was founded by students from University of ?Indiana?[/UNQUOTE]

    One of the directors (Dan Sandin) at the Electronic Visualization Lab at the University of Illinois at Chicago (UIC) developed pscholograms — has now moved on to make something called a varrier (variable barrier) display…

    Donna Cox at Urbana (who moved on from EVL) made some pscholographic art, too.

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