Image Processing

简单来讲就是 image in > image out

有两种image processing的方法：

1. spatial domain operation
   • point operation: g(x, y) = T(f(x, y));
   • neighbourhood operation: g(x, y) = T(f(x, y), f(x+1, y), f(x-1, y)...)

contrast stretching;

• Intensity thresholding (Automatic);
  • Otsu's method;
  • iso-data method;
  • multi-level thresholding method;
  • intensity inversion

Log transformation;
Power transformation;
piecewise transformation;

• bit plane

• histogram: count the number of pixels having that level

  • histogram processing
    • histogram equalisation
    • histogram specification

• Image enhancement

  • image averaging
  • filtering (e.g used for blurring, noise reduction)
    • smoothing filter
      • mean filtering(average)
      • Gaussian filter
    • order-statistics filters: median, min, max
  • pooling
  • sharpening spatial filters-edge detection
    • gradient
    • Laplacian
    • combining
    • padding

2. frequency domain