Results 1 to 4 of 4

Thread: Striped Line Disrtrtions

Hybrid View

Previous Post Previous Post   Next Post Next Post
  1. #1
    Guild Journeyer Thurlor's Avatar
    Join Date
    Apr 2011
    Location
    Phillip Island, Victoria, Australia
    Posts
    126

    Question Striped Line Disrtrtions

    Hey all,

    Was wondering if someone here could explain to me why fill patterns of parallel lines seems to form crazy hatch patterns when zooming in or out. Does the same thing happen in the real world or only with monitors? If my written explanation is too vague I'll find some pics.

  2. #2
    Community Leader Guild Sponsor - Max -'s Avatar
    Join Date
    Dec 2012
    Location
    France
    Posts
    4,220

    Default

    I understand what you mean. It only appears on monitor screen, you won't have this strange visual effect when print.

  3. #3
    Guild Master Falconius's Avatar
    Join Date
    Jul 2013
    Location
    Israel
    Posts
    2,727

    Default

    It's due to the way pixels are arranged in a grid, it's why on tv they make sure not to wear clothes that will cause that problem (checkered patterns etc.), you have the same thing in CRT screens. What I think happens is that the pixels get a read pattern of colour/ no colour because the colours fall in between where they display on the screen... only I'm sure there is some way to express that in a way that makes sense...

  4. #4
    Administrator waldronate's Avatar
    Join Date
    Mar 2007
    Location
    The High Desert
    Posts
    3,549

    Default

    Falconius describes part of the problem. The real problem is how the image is sampled. A quick internet search on "image resampling" and "moire patterns" and "aliasing" will turn up a lot of discussions on the subject. The (overly) short version is that if you make an image smaller by just picking a pixel at a multiple of the image size (e.g. shrinking an image to 1/3 its size by picking every third pixel), then any pattern that happened to be in the original image at every third pixel will be made more apparent. A grid, for example, might drop out lines and a pattern that is composed of every other sample will show as a larger checkerboard pattern. Very broadly speaking, shrinking an image involves using all pixels in the source image to produce the destination image (typically, a blur as big as your shrink ratio is a good starting point); enlarging an image involves trying to create detail at the right scale to avoid artifacts like blockiness and ringing. http://www.cartographersguild.com/tu...explained.html has some good discussions on the subject.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •