Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Cleaning out the hall closet

  1. Jan 30, 2014 #1
    I found this old dot matrix of my children. It was printed on a calendar at Sears.

    30ie5i9.jpg

    How did they do that?? I know they took a regular picture first.
     
  2. jcsd
  3. Jan 30, 2014 #2

    jedishrfu

    Staff: Mentor

    My guess is they used the pixels of your Black and White image and mapped a character with a corresponding density of dots. In addition the algorithm was probably was sensitive to sudden pixel changes and would try to find the best character to map. As an example if the pixel to the left and the pixel below a given pixel were dark but the pixel itself was white then the might use an '[' or an 'L'...

    Code (Text):

    #############
    ##[_______]##
    #############
     
    Sample palette:

    Code (Text):

    light gray:

    ..........
    ..........
    ..........
    ..........
    ..........

    darker gray:

    XXXXXXXXXX
    XXXXXXXXXX
    XXXXXXXXXX
    XXXXXXXXXX
    XXXXXXXXXX

    black:

    ##########
    ##########
    ##########
    ##########
    ##########

     
    so basically you could make a palette of characters to map to various shades of gray and then use that to construct the character based image. It was very popular before the advent of PCs and color printers.

    Here's a program that do it:

    http://www.glassgiant.com/ascii/

    and google has many pictures organized unde the search term "Ascii Art":

    https://www.google.com/search?q=asc...rEMMiIyAH1rYGgCA&ved=0CDAQsAQ&biw=969&bih=609

    and here's another explanation of how it works:

    http://stackoverflow.com/questions/394882/how-do-ascii-art-image-conversion-algorithms-work
     
    Last edited: Jan 30, 2014
  4. Jan 30, 2014 #3
    opps, I forgot the year it was made.

    23sd5yb.jpg

    So how do I get a full size dot matrix Ferrari image on my garage door?
     
  5. Jan 30, 2014 #4

    jedishrfu

    Staff: Mentor

    Get one of those projecters that hook to a computer and display an image on your garage door and then trace out the image and then paint it on manually. Or better yet, hire some out of work grafitti artist or custom van painter to spray paint it on.
     
  6. Jan 30, 2014 #5
    The Home owners association won't allow a painted on picture. I had hoped they might go for something less noticeable like a lot of little dots.

    Thanks much for your help and the links.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Cleaning out the hall closet
  1. My closet (Replies: 8)

Loading...