Table 7 Entropic measure value comparison between results obtained using different enhancement methods on standard benchmark face datasets
Database | LCS | HE | IIA | M_PSO | M_GA | BDPFHE | CLAHE | LLIE | Proposed |
|---|---|---|---|---|---|---|---|---|---|
AR | |||||||||
 Image 1 | 7.4463 | 5.9567 | 7.4463 | 7.7381 | 7.7415 | 7.2321 | 7.8153 | 7.4387 | 7.7312 |
 Image 2 | 7.1931 | 5.9504 | 7.1931 | 7.6573 | 7.6578 | 6.8574 | 7.6891 | 7.1804 | 7.8393 |
 Image 3 | 7.413 | 5.931 | 7.413 | 7.6654 | 7.661 | 7.0664 | 7.7904 | 7.2489 | 7.7804 |
 Image 4 | 7.635 | 5.9717 | 7.635 | 7.7815 | 7.786 | 7.2305 | 7.7595 | 7.0171 | 7.8593 |
 Image 5 | 7.5609 | 5.8266 | 7.5609 | 7.5745 | 7.5721 | 7.1865 | 7.708 | 7.0508 | 7.8258 |
 Image 6 | 7.0688 | 5.8843 | 7.0688 | 7.4651 | 7.4632 | 6.6483 | 7.5923 | 6.3949 | 7.3507 |
YF | |||||||||
 Image 1 | 4.2938 | 3.1034 | 4.2938 | 4.6969 | 4.6444 | 4.1962 | 4.4254 | 4.1136 | 4.5492 |
 Image 2 | 4.7103 | 3.4205 | 4.7103 | 4.8841 | 4.8882 | 4.5318 | 4.8105 | 4.1881 | 4.6918 |
 Image 3 | 4.6965 | 3.4164 | 4.6965 | 4.2898 | 4.0718 | 4.5828 | 4.8450 | 3.7340 | 4.9105 |
 Image 4 | 5.2128 | 3.8475 | 5.2128 | 5.2600 | 5.2511 | 4.9808 | 5.3399 | 4.7239 | 5.0825 |
 Image 5 | 3.8014 | 2.7607 | 3.8014 | 3.4162 | 3.4312 | 3.6916 | 3.9933 | 3.8220 | 3.9198 |
 Image 6 | 3.8665 | 2.7464 | 3.8665 | 3.6413 | 3.3834 | 3.7931 | 3.9946 | 3.7089 | 3.8903 |
ORL | |||||||||
 Image 1 | 7.2911 | 5.9766 | 7.2911 | 7.7474 | 7.7194 | 7.1604 | 7.7833 | 7.3308 | 7.4561 |
 Image 2 | 7.4287 | 5.9811 | 7.4287 | 7.7244 | 7.7241 | 7.3292 | 7.8739 | 7.4295 | 7.2415 |
 Image 3 | 7.3419 | 5.9719 | 7.3419 | 7.7132 | 7.705 | 7.2402 | 7.8589 | 7.5324 | 7.2677 |
 Image 4 | 7.3675 | 5.9542 | 7.3675 | 7.5777 | 7.6382 | 7.2482 | 7.8178 | 7.646 | 7.7055 |
 Image 5 | 7.3794 | 5.9636 | 7.3794 | 7.4041 | 7.3967 | 7.2621 | 7.8876 | 7.6182 | 7.9296 |
 Image 6 | 7.4323 | 5.9823 | 7.4323 | 7.6305 | 7.6103 | 7.2897 | 7.8693 | 7.7043 | 7.1986 |