| quantization step (Δb) | DCT on the coefficients of approximations | DCT on the coefficients of details | ||
| CF (%) | PRD (%) | CF (%) | PRD (%) | |
| 10−4 | 97.02 | 27.7 | 97.39 | 26.82 |
| 10−5 | 92.76 | 0.29 | 93.72 | 2.75 |
| 10−6 | 87.56 | 0.03 | 88.24 | 0.28 |
| 10−7 | 86.67 | 27.05 | 87.03 | 0.03 |