1. Intensity Transform Contrast Stretching Y ← u0+γ*(Y-u)/s
Log-transform (medical images, etc.)
Y ← β*(log2 (1+Y))-1, e.g., β=32
16-bit  8-bit representation
Y ← (1+Y)1/2 -1, or Y ← Y/257
Negative Image
Y ← 255-Y
Mean Filtering
Median Filtering
Histogram Equalization

2. Results of Contrast Stretching

3. Log-transform and Negative

4. Mean and Median Filtering1 2 9 1 2
Mean of 9 pixel values
Median of 9 pixel values 1 2

5. Histogram Equalization (1)

6. Histogram Equalization (2)

7. Histogram Equalization (3)

8. Histogram Equalization (4)

9. Histogram Equalization (5)

10. Histogram Equalization (6)