1. Lecture Five
Figures from Gonzalez and Woods, Digital Image Processing, Second edition, Prentice-Hall,2002.

2. Histogram Processing r_k is gray value n_k is frequency
A histogram of an image is the graph of the frequencies of the gray level in the range [0,L-1].
r_k is gray value
n_k is frequency

3. Probability Function

4. Histogram Function(1)
Dark Images- Histogram components are concentrated on dark side
Bright images- Components on light side
Low-contrast images- Components clustered
High contrast images- Spread out.

5. Image Enhancement in the
Chapter 3
Image Enhancement in the
Spatial Domain

6. Histogram Function (2)
Normalize gray level to interval [0,1], r<- r/(L-1)
Thus

7. Histogram Function (3)
We need to compute

8. Image Enhancement in the
Chapter 3
Image Enhancement in the
Spatial Domain

9. Image Enhancement in the
Chapter 3
Image Enhancement in the
Spatial Domain

10. Image Enhancement in the
Chapter 3
Image Enhancement in the
Spatial Domain

11. Image Enhancement in the
Chapter 3
Image Enhancement in the
Spatial Domain