Given the following gray level histogram of an image. Compute the gray levels after histogram equalization.
| Gray Level | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| Frequency | 200 | 500 | 40 | 600 | 800 | 60 | 1800 | 1000 |
SOLUTION
| Gray Value | Frequency(n) | Probability (n/sum n) | Cumulative (sr) | Sr*(L-1) | Round Off |
| 0 | 200 | 0.04 | 0.04 | 0.04*(8-1) =0.28 | 0 |
| 1 | 500 | 0.1 | 0.14 | 0.98 | 1 |
| 2 | 40 | 1\125 | 0.148 | 1.036 | 1 |
| 3 | 600 | 0.12 | 0.268 | 1.876 | 2 |
| 4 | 800 | 0.16 | 0.428 | 2.996 | 3 |
| 5 | 60 | 0.012 | 0.44 | 3.08 | 3 |
| 6 | 1800 | 0.36 | 0.8 | 5.6 | 6 |
| 7 | 1000 | 0.2 | 1 | 7 | 7 |
| Sum=5000 | Sum=1 |
Gray Level after histogram equalization
| Gray Value | Frequency(n) |
| 0 | 200 |
| 1 | 540 |
| 2 | 600 |
| 3 | 860 |
| 6 | 1800 |
| 7 | 1000 |




