Antialiasing

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Antialiasing
jaggies
digitized
Analog line
Digital line aliasing occurs
Aliased 'W'
Antialiased 'W'
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Antialiasing
What anti-aliasing attempts to do is, using
mathematics, fill in some of the digital system
with colors that are in-between the two adjoining
colors. In this case a medium gray would be
between the black and the white. Some gray
squares placed in the grid might help soften up
the "jaggies"
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Antialiasing
4
Unweighted Area Sampling

• Intensity is proportional to the amount of area
  covered.
• Defining the box weighting function which has
  volume of 1 (Imax).
• Determine the overlap volume Ws 0, 1.

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Weighted Area Sampling
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Antialiasing in Practice

• Use of low pass filter by summing products
  between the mask coefficients and the
  intensities of the pixels under the mask.
• For w which is a 3x3 mask, the response R at
  the center of the mask is R w1z1 w2z2
  w9z9

mask
R
mask
R
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Antialiasing in Practice
(a)
(b)