Computer Vision Foundations · 免费预览

冲激串与频谱复制

将采样建模为与冲激串相乘，表明采样后的频谱是原始频谱的无穷多个平移副本，而混叠就是这些副本的重叠。

1. Sampling as multiplication

Sampling as multiplication

A train transforms to a train

The spectrum becomes its own wallpaper

What the model buys

The Fourier transform of the delta train is another delta train with spacing 2π/Ts. What is the underlying principle?

In the replicated spectrum, what precisely is aliasing, and what does reducing Ts do to it?

Sampling uses period $T_s = 1/4$ . Write the spacing $2\pi/T_s$ of the spectral copies.

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