Table 1.
Quantitative evaluation of enhancement methods for image criteria improvement. Bold numbers represent the best or equally best performance in each metric.
| Metrics | Scene | Reference (WLI w/A3) | IHb color enhancement [9] | WLI w/A8 [9] | HE | M1 [16] | Proposed TXI mode1 | Proposed TXI mode2 |
|---|---|---|---|---|---|---|---|---|
| Illumination uniformity (standard deviation) | Esophagus | 37.165 | 39.134 | 37.323 | 60.222 | 58.102 | 33.353 | 33.643 |
| Stomach | 19.016 | 20.979 | 19.086 | 33.759 | 26.553 | 19.108 | 19.293 | |
| Colon | 19.315 | 19.737 | 19.583 | 33.439 | 44.775 | 19.344 | 19.424 | |
| Average | 25.165 | 26.617 | 25.330 | 42.473 | 43.143 | 23.935 | 24.120 | |
|
| ||||||||
| Color (ΔE) | Esophagus | 8.004 | 9.120 | 9.586 | 15.221 | 19.228 | 16.026 | 13.474 |
| Stomach | 4.471 | 5.055 | 5.102 | 7.619 | 7.441 | 12.364 | 8.542 | |
| Colon | 5.590 | 6.596 | 6.254 | 5.666 | 13.375 | 15.407 | 9.887 | |
| Average | 6.022 | 6.924 | 6.981 | 9.502 | 13.348 | 14.599 | 10.634 | |
|
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| Contrast (EBCM) | Esophagus | 5.264 | 5.244 | 9.117 | 8.898 | 6.319 | 10.176 | 10.132 |
| Stomach | 5.167 | 5.175 | 8.839 | 7.780 | 6.630 | 9.865 | 9.830 | |
| Colon | 4.909 | 4.842 | 9.094 | 8.582 | 9.709 | 9.829 | 9.856 | |
| Average | 5.114 | 5.087 | 9.017 | 8.420 | 7.552 | 9.957 | 9.939 | |
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| Naturalness (SSIM) | Esophagus | 1.000 | 0.995 | 0.970 | 0.839 | 0.534 | 0.852 | 0.926 |
| Stomach | 1.000 | 0.996 | 0.977 | 0.827 | 0.563 | 0.916 | 0.957 | |
| Colon | 1.000 | 0.997 | 0.982 | 0.836 | 0.029 | 0.930 | 0.973 | |
| Average | 1.000 | 0.996 | 0.977 | 0.834 | 0.375 | 0.899 | 0.952 | |