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Imaging Basics (Medical Imaging Overview (non-invasive visualisation of…

- - - - I-I background/I background
      - -1 to infinty
      - used for small features on homogeneous background
    - - I max - I min / I max + I min
      - 0 to 1
      - used for sine gratings where max and min have similar coverages
      - sometimes it can produce the same results, even though the image looks visibly different, so its unreliable
  - - - modulation transfer function
        
        characterises the capability of the imaging system to transfer contrast from the input object to image contrast at different spatial frequencies
        
        = spatial frequency response of the system
    - - sharp edges on image lead to higher frequency
      - characterises patterns in time domains
      - function of time as a signal
    - - quick algorithm that calculates discrete Fourier transform (DFT)
      - gives brightest amplitude of spatial frequency
- - - - originates from rounding error between true analogue input to ADC and output digisted value
    - - orginates from random variations in current or voltage cause by random electrons carring current by thermal energy
        
        increases with increased temp
    - - electronic noise due to finite number of particles carrying energy
        
        magnitude of noise increase when magnitude of measurement varibale 9current or light intensity
        
        often only a problem with small currents or light intensities
- - - - anatomy
    - - anatomy
  - - - anatomy
    - - function
    - - function
    - - anatomy