168 471 Computer Graphics, KKU. Lecture 91 Antialiasing Aliased 'W'Antialiased 'W' digitized Analog...
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Transcript of 168 471 Computer Graphics, KKU. Lecture 91 Antialiasing Aliased 'W'Antialiased 'W' digitized Analog...
168 471 Computer Graphics, KKU. Lecture 9
1
Antialiasing
Aliased 'W' Antialiased 'W'
digitized
Analog line Digital line: aliasing occurs
jaggies
168 471 Computer Graphics, KKU. Lecture 9
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Antialiasing
- What anti aliasing attempts to do is, using mathematics, fill i
n some of the digital system w - ith colors that are in between t he two adjoining colors. In this
case a medium gray would be between the black and the whi
te. Some gray squares placed in the grid might help soften u
p the "jaggies"
168 471 Computer Graphics, KKU. Lecture 9
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Antialiasing
168 471 Computer Graphics, KKU. Lecture 9
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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].•
168 471 Computer Graphics, KKU. Lecture 9
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Weighted Area Sampling
168 471 Computer Graphics, KKU. Lecture 9
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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
RR
maskmask
168 471 Computer Graphics, KKU. Lecture 9
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Antialiasing in Practice
(a) (b)