Table 4.
Performance of noise reduction techniques evaluated using SNR and spot efficiency for images with blurring and non-uniformbackground distribution
| Image anomaly | Noise reduction technique | SNR (dB) | Spot efficiency (%) | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Blurring | N (pixels) | 5 | 10 | 15 | 20 | 25 | 30 | 5 | 10 | 15 | 20 | 25 | 30 |
| Wavelet | 34.8 | 26.2 | 21.6 | 18.4 | 16.1 | 14.3 | 98 | 96 | 90 | 80 | 66 | 54 | |
| Contourlet | 35.3 | 26.3 | 21.6 | 18.4 | 16.1 | 14.3 | 98 | 96 | 90 | 81 | 65 | 53 | |
| TV | 22.6 | 22.2 | 20.6 | 17.9 | 16.8 | 14.2 | 91 | 92 | 89 | 82 | 63 | 54 | |
| WVTV | 25.4 | 24.3 | 20.7 | 17.9 | 15.9 | 14.2 | 93 | 94 | 89 | 82 | 63 | 55 | |
| Non-uniform background | Distortion (%) | 5 | 10 | 15 | 20 | 25 | 30 | 5 | 10 | 15 | 20 | 25 | 30 |
| Wavelet | 21.5 | 19.8 | 17.9 | 15.7 | 12.9 | 9.2 | 99 | 98 | 99 | 97 | 97 | 97 | |
| Contourlet | 21.5 | 19.8 | 17.9 | 15.7 | 12.9 | 9.2 | 99 | 99 | 99 | 98 | 98 | 96 | |
| TV | 19.3 | 18.3 | 16.9 | 15.1 | 16.7 | 9.1 | 92 | 92 | 92 | 92 | 94 | 94 | |
| WVTV | 20.3 | 19.0 | 17.4 | 15.4 | 12.8 | 9.1 | 98 | 97 | 98 | 97 | 96 | 96 | |
Note: The values in bold indicate the best SNR and spot efficiency for each noise level. N (pixels) represents the number of pixels used to simulate blurring effect. Distortion (%) is the percentage of degradation used for the non-uniform background.