Antialiasing Dr Scott Schaefer 1 What is aliasing

Antialiasing Dr. Scott Schaefer 1

What is aliasing? 2/74

What is aliasing? 3/74

What is aliasing? 4/74

What is aliasing? 5/74

Why Does Aliasing Exist? n Nyquist Limit: Must sample more than twice the maximum frequency 6/74

Why Does Aliasing Exist? n Nyquist Limit: Must sample more than twice the maximum frequency 7/74

Why Does Aliasing Exist? n Nyquist Limit: Must sample more than twice the maximum frequency 8/74

Why Does Aliasing Exist? n Nyquist Limit: Must sample more than twice the maximum frequency 9/74

Why Does Aliasing Exist? n Nyquist Limit: Must sample more than twice the maximum frequency 10/74

Why Does Aliasing Exist? n Nyquist Limit: Must sample more than twice the maximum frequency 11/74

Why Does Aliasing Exist? n Nyquist Limit: Must sample more than twice the maximum frequency 12/74

Why Does Aliasing Exist? n Nyquist Limit: Must sample more than twice the maximum frequency 13/74

Aliasing in Computer Graphics Polygons n Textures n 14/74

Aliasing in Computer Graphics Polygons n Textures n 15/74

Aliasing in Computer Graphics Polygons n Textures n 16/74

Aliasing in Computer Graphics Polygons n Textures n 17/74

Aliasing in Computer Graphics Polygons n Textures n 18/74

Aliasing in Computer Graphics Polygons n Textures n 19/74

Aliasing in Computer Graphics Polygons n Textures n 20/74

Removing Aliasing n Two options: u Filter out high-frequencies after drawing u Filter out high-frequencies before drawing 21/74

Multisampling n Sample multiple times per pixel 22/74

Multisampling n Sample multiple times per pixel 2 x 2 Grid 23/74

Multisampling n Sample multiple times per pixel Rotated Grid 24/74

Multisampling n Sample multiple times per pixel 4 x 4 Checker 25/74

Multisampling n Sample multiple times per pixel 8 Rooks 26/74

Coverage Sampling Antialiasing Full pixel samples (shader) are too expensive n Sample color and coverage separately n 27/74

Texture Filtering 28/74

Texture Filtering 29/74

Removing High Frequencies 30/74

Removing High Frequencies 31/74

Removing High Frequencies Fourier 32/74

Removing High Frequencies Fourier 33/74

Removing High Frequencies Fourier 34/74

Filtering 35/74

Filtering Fourier 36/74

Filtering Fourier 37/74

Filtering Fourier 38/74

The Ideal Filter… Not So Ideal 39/74

The Ideal Filter… Not So Ideal Negative values 40/74

The Ideal Filter… Not So Ideal Infinite support 41/74

Common Filters Filter Fourier Transform Box 42/74

Common Filters Filter Fourier Transform blurring Box 43/74

Common Filters Filter Fourier Transform aliasing Box 44/74

Common Filters Filter Fourier Transform Tent 45/74

Common Filters Filter Fourier Transform Lanczos 3 46/74

Filtering Images 47/74

Filtering Images 48/74

Filtering Images 49/74

Mipmapping: Realtime Filtering 50/74

Mipmapping: Realtime Filtering 51/74

Mipmapping: Realtime Filtering 52/74

Mipmapping: Realtime Filtering 53/74

Mipmapping: Realtime Filtering 54/74

Mipmapping: Realtime Filtering 55/74

Mipmapping: Realtime Filtering 56/74

Mipmapping: Realtime Filtering 57/74

Mipmapping: Realtime Filtering 58/74

Mipmapping: Realtime Filtering 59/74

Mipmapping: Realtime Filtering 60/74

Mipmapping: Realtime Filtering 61/74

Anisotropic Filtering 62/74

Anisotropic Filtering 63/74

Anisotropic Filtering 64/74

Anisotropic Filtering 65/74

Mipmapping 66/74

Anisotropic Mipmapping 67/74

Analytic Antialiasing 68/74

Analytic Antialiasing 69/74

Simple Analytic Antialiasing 70/74

Simple Analytic Antialiasing 71/74

Simple Analytic Antialiasing 72/74

Analytic Antialiasing 73/74

Analytic Antialiasing 74/74

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Morphological Antialiasing 76/74