1. Discussion #29 – Images II
Image Processing
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Discussion #29 – Images II

2. Discussion #29 – Images II
Increasing Contrast y
f(x) y
f(x) x x
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Discussion #29 – Images II

3. How Contrast Functions Work
Index into the Input Array of brightness (index = brightness)
Get the corresponding brightness value from the Output Array
What does this function do?
Brightness
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Discussion #29 – Images II

4. Discussion #29 – Images II
Increase Brightness
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Discussion #29 – Images II

5. Discussion #29 – Images II
Decrease Brightness
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Discussion #29 – Images II

6. Histogram Thresholding
thresholding creates a binary image by converting pixels according to a threshold value
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Discussion #29 – Images II

7. Discussion #29 – Images II
Histogram Stretching
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Discussion #29 – Images II

8. Histogram Stretching Algorithm
Find darkest pixel = D
Find lightest pixel = L
Let max possible pixel value = M
Then the new value for every pixel in the image
is:
New pixel value = x M
(Old pixel value – D)
(L – D)
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Discussion #29 – Images II

9. Discussion #29 – Images II
Inversions
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Discussion #29 – Images II