imgproc模块/linear filter

Linear filter

• Normalized Box Filter/最简单的滤波器
  

  • blur(src, dst, Size(w,h), Point(-1,-1));
  • src: Source image
  • dst: Destination image
  • Size(w, h): Defines the size of the kernel to be used
  • Point(-1, -1): Indicates where the anchor point(the pixel evaluated)
    is located with respect to the neighborhood.

• Gaussian Fliter/最实用但并不是最快的的滤波器

  • GaussianBlur(src, dst, Size(i,i), 0,0);
  • 最后两个参数代表是往x方向求导还是y方向，两个都为0，则代表使用kernel size

• Median Filter 中值滤波器

  • 遍历每个像素并用周围像素的中值代替该像素
  • medianBlur(src, dst, i);
    
    • i: Size of the kernel(only one because we use a square window, and it must be odd)

• Bilateral Filter/为了避免滤波器不仅消除了噪声，且将边缘也消融了。

  • bilateralFilter(src, dst, i, i*2, i/2);
    
    • i: the diameter of each pixel neighborhood
    • i*2: Standard deviation in the color space
    • i/2: Standard deviation in the coordinate space.