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Noise Filtering 噪音過濾

Aims 宗旨​

  • Intensity Images 強度圖像
  • Noise Reduction 噪音過濾
  • Edge Detection 邊緣檢測

Optical Illusion 光學幻覺​

https://www.ted.com/talks/beau_lotto_optical_illusions_show_how_we_see

Noise 噪音​

  • It turns out we will need to remove noise 事實證明我們需要去除噪音
  • There are many noise filters 有很多種噪音濾波器
  • We can implement most of them using the idea of convolution again 我們可以使用卷積的概念來實現它們
  • e.g. Mean filter 平均濾波器

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Noise filtering 噪音過濾​

  • We can use convolution to remove noise as we mentioned, e.g. mean filter 平均濾波器

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  • This is a linear filter 線性濾波器

  • The most widely used is Gaussian filtering 高斯濾波器

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Effect of mean filtering 平均濾波器​

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Effect of Gaussian filtering 高斯濾波器​

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Sequenced filters 連續濾波器​

We can replace a 2D Gaussian filter with 2, 1D Gaussian filters in sequence 我們可以依次用 2、1D 高斯濾波器替換 2D 高斯濾波器

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Laplacian Operator 拉普拉斯算子​

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Highly Directed Work 高度導向的工作​

  • Second order operators 二階運算符
  • Laplacian 拉普拉斯算子
  • Laplacian of Gaussian 高斯拉普拉斯算子
  • Gaussian (Canny) edge detection 高斯邊緣檢測
  • Thresholding 閾值化