Table 3. Effects of SS-DWT on lossless JPEG 2000 bitrates for BH, RH, fixed SS-DWT variants, and for choosing among fixed transform variants.
| Transform variant | Complexity | Time | Images | ||||
|---|---|---|---|---|---|---|---|
| rel. | Photo | No-photo | No-photo (a) | No-photo (b) | All | ||
| r DWT | TD + TE + TR | 1.00 | 3.9975 | 2.9162 | 3.2882 | 2.7348 | 3.6395 |
| ΔrBH(1) | 5.33 TD + 7.33 TE + TR | 6.03 | -0.75% | -15.25% | -32.26% | -6.96% | -5.55% |
| ΔrBH(2) | 9.67 TD + 12.67 TE + TR | 10.30 | -0.86% | -15.66% | -32.28% | -7.54% | -5.76% |
| ΔrRH(1) | 3.42 TD + 5.33 TE + TR | 4.41 | -0.97% | -15.66% | -32.26% | -7.56% | -5.84% |
| ΔrRH(2) | 5.83 TD + 8.67 TE + TR | 7.07 | -0.98% | -15.73% | -32.28% | -7.65% | -5.86% |
| ΔrNO_DWT | 0.00 TD + 1.00 TE + TR | 0.95 | 25.59% | 18.77% | -22.65% | 38.98% | 23.33% |
| ΔrDWT, NO_DWT | 1.00 TD + 2.00 TE + TR | 1.76 | -0.01% | -7.43% | -22.65% | 0.00% | -2.47% |
| ΔrFIX1 | 0.50 TD + 1.00 TE + TR | 0.97 | 0.15% | -10.94% | -22.07% | -5.51% | -3.52% |
| ΔrFIX1, DWT | 1.22 TD + 1.75 TE + TR | 1.58 | -0.46% | -11.14% | -22.07% | -5.80% | -3.99% |
| ΔrFIX1, DWT, NO_DWT | 1.22 TD + 2.75 TE + TR | 2.34 | -0.47% | -13.10% | -28.05% | -5.80% | -4.65% |
| ΔrFIX2 | 0.38 TD + 1.00 TE + TR | 0.97 | 0.30% | -14.11% | -29.27% | -6.72% | -4.47% |
| ΔrFIX2, DWT | 1.19 TD + 2.00 TE + TR | 1.77 | -0.39% | -14.25% | -29.27% | -6.93% | -4.98% |
| ΔrFIX2, DWT, NO_DWT | 1.19 TD + 3.00 TE + TR | 2.53 | -0.40% | -15.13% | -31.93% | -6.93% | -5.27% |
| ΔrFIX1, FIX2 | 0.50 TD + 1.67 TE + TR | 1.48 | -0.24% | -14.53% | -29.28% | -7.33% | -4.97% |
| ΔrFIX1, FIX2, DWT | 1.22 TD + 2.42 TE + TR | 2.09 | -0.62% | -14.61% | -29.28% | -7.45% | -5.25% |
| ΔrFIX1, FIX2, DWT, NO-DWT | 1.22 TD + 3.42 TE + TR | 2.84 | -0.62% | -15.48% | -31.93% | -7.45% | -5.54% |
rDWT−average lossless JPEG 2000 bitrate for 3-level unmodified DWT (bpp); Δrvariant_list−average bitrate change obtained using the best out of the listed variants; Complexity–compression process computational time complexity including complexity of heuristic or variant selection; Time rel.–compression time relative to time of unmodified JPEG 2000 compression.