IMAGE 1

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IMAGE 1
An image is a two dimensional Function f(x,y)
where x and y are spatial coordinates And f at
any x,y is related to the brightness at that
point A digital image is a 2D representation of
a continuous image by a 2D array of discrete
samples Each element of the 2D array is a pixel.
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Definition

• Histograms count the number of occurrences of
  each possible value

Count
Grey level
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Properties

• Sum of all values in the histogram equals the
  total number of pixels

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Properties

• Sum of all values between a and b equals the area
  of all objects in that range

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Properties

• Integrated optical density
• Mean greylevel

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Application Adjusting Camera Parameters

• Too bright - lots of pixels at 255 (or max)
• Too dark - lots of pixels at 0
• Gain too low - not enough of the range used

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Application Segmentation

• Can be used to separate bright objects from dark
  background (or vice versa)

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Normalizing Histograms

• Probability density function histogram
  normalized by area

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Cumulative Histograms

• Counts pixels with values up to and including the
  specified value

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Cumulative Density Functions

• Normalized cumulative histograms

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IMAGE 1
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Image 1 Bright
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Image 1 Dark
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Image 1 Low contrast
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Image 1 High contrast
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RESOLUTION
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INTERPOLATION
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HISTOGRAM EQUALIZATION
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THRESHOLDING
104
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199
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34
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137
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Inverted
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SMOOTH 3
SMOOTH 7
MEDIAN 5
MEDIAN 3