Manav Goyal

Introduction - Image Processing

  • Image Processing Fields
    • Computer Graphics -=> The creation of images
    • Image Processing -=> Enhancement or other manipulation of the image
    • Computer Vision -=> Analysis of the image content
  • Image Sampling & Quantization
    • The output of most sensors is continuous in amplitude and spatial coordinates
    • Used to convert analog image into digital image
    • Components
      • Coordinates
      • Intensity/Amplitude
    • Sampling
      • Process of digitizing of coordinates of analog image and into digital image
      • Nyquist sampling rate
        • 2 * Maximum Frequency
        • Aliasing
    • Quantization
      • Process of digitizing of amplitude of analog image and into digital image
      • Rounding off
      • Truncation
    • Steps
      • Dividing axis in equal parts
      • 3-bit Quantizer
        • Convert points into bits
        • High intensity area will get higher pixel value (Up to 255)
    • Representing Digital Images
      • Pixel intensity levels (gray scale levels) are in the interval of [0, L-1]
      • L = 2k
      • Bits required to store a digitized image, b = M * N * k
      • Basic Relationship of Pixels
        • Image Not Loaded
      • Neighbors of a Pixel
        • N4(P) = 4-neighbors -=> Considers only vertical and horizontal neighbors
        • N8(P) = 8-neighbors -=> Considers all neighbors
        • ND(P) = 4-neighbors -=> Considers diagonal neighbors
      • Connectivity
        • Image Not Loaded
      • Adjacency
        • A pixel p is adjacent to pixel q then they are said to be connected
        • Type -=> 4-adjacency, 8-adjacency, m-adjacency
      • Path
        • A path from pixel p at (x,y) to pixel q at (s,t) is a sequence of distinct pixels
        • Type -=> 4-path, 8-path, m-path
      • Distance Measure
        • Euclidean
          • Image Not Loaded
        • City block
          • D4(p,q) = |x - s| + |y - t|
        • Chessboard
          • D8(p,q) = max(|x - s|, |y - t|)
      • Distance Measure of Path
      • Path Length
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