On Tue, 22 Apr 2003, Christopher James Huff wrote:
>In article <Pine.GSO.4.53.0304221845420.6559@blastwave>,
> Dennis Clarke <dcl### [at] blastwaveorg> wrote:
>
>>   In what way is antialiasing within a single pixel different from blur of
>>  a single pixel.
>
>You can't blur a pixel, you need a set of pixels. The algorithm used is
>somewhat similar, but the goal and result are different. Blurring
>removes information from an image, spreading colors out across adjacent
>pixels.

  well .. not really.  If by "blur" we mean the optical result of an image
 being out-of-focus then the data is all there, simply not arranged in a
 fashion that people prefer.  A digital blur of a digital image by way of
 a gaussian ( or similar algorithm ) approach merely distributes the data.
 There are algorithms that will un-blur an image.  These are the same tools
 that are used to unblur the linear movement of a projectile or the rotation
 of an engine component within a photograph.

> Antialiasing adds data, coloring each pixel with the overall
>color of the area it covers instead of a single point within that area,
>and is not dependant on the colors of adjacent pixels.

  ok .. I'm with you on that.  We are talking about using multiple sample
  points within a pixel then, probably distributed as a square matrix of
  samples.  This would be the same then as simply having a higher resolution
  image and then doing a blur of the pixels on a block by block basis while
  ignoring neighbors.  At least that is how I perceive the issue.  The
  removal of jagged edges on lines and sharp boundaries can be achieved with
  either a high resolution image blured or a low-resolution image with a
  multi-sample per pixel approach.

> You can use an
>antialiasing algorithm with a large image as input, but you will get a
>smaller image as a result.

  well yes, that is clear.  It makes no difference whether you sample each
  pixel 9 times ( 3x3 ) within a 100x100 data array or simply blur the 3x3
  pixel blocks of a 300x300 data array to produce a 100x100 result set. I
  think, however, that the result from the latter would be smoother than the
  former.

Dennis

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