Changeset 2175


Ignore:
Timestamp:
Dec 29, 2007, 11:35:52 PM (12 years ago)
Author:
Sam Hocevar
Message:
  • A few fixes here and there.
File:
1 edited

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  • www/study/part3.html

    r2174 r2175  
    370370
    371371<p> Dot diffusion was reinvented 14 years later by Arney, Anderson and Ganawan
    372 without crediting Knuth. They call their method <b>omni-directional error
    373 diffusion</b>. Instead of using a clustered dot matrix like dot diffusion,
    374 they use a dispersed dot matrix. This is a 16×12 portion of that matrix: </p>
     372without even citing Knuth. They call their method <b>omni-directional error
     373diffusion</b>. Instead of using a clustered dot matrix like Knuth recommends
     374for dot diffusion, they use a dispersed dot matrix, which gives far better
     375results on a computer display. This is a 16×12 portion of that matrix: </p>
    375376
    376377<p style="text-align: center;">
     
    379380</p>
    380381
    381 <p> The recommended implementation of omni-directional error diffusion uses
     382<p> The preferred implementation of omni-directional error diffusion uses
    382383a slightly different propagation matrix, where top and bottom neighbours get
    383384more error than the others: </p>
     
    395396
    396397<p> Small error diffusion matrices usually cause artifacts to appear because
    397 the error is not propagated in enough directions. Ostromoukhov suggest error
    398 diffusion values that vary according to the input value. The list of 256
    399 discrete value triplets for <i>d1</i>, <i>d2</i> and <i>d3</i> he provides
    400 give pretty good results with serpentine parsing: </p>
     398the error is not propagated in enough directions. At the same time, such
     399matrices also reduce the sharpened aspect common in error diffusion
     400techniques. </p>
     401
     402<p> Ostromoukhov suggests error diffusion values that vary according to the
     403input value. The list of 256 discrete value triplets for <i>d1</i>, <i>d2</i>
     404and <i>d3</i> he provides give pretty good results with serpentine parsing:
     405</p>
    401406
    402407<p style="text-align: center;">
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