36.5.4.1 Scaling, Decimation (Subsampling)
This module resizes captured 8-bit color sensor images to fit the LCD display format. The resize module performs only downscaling. The same ratio is applied for both horizontal and vertical resize, then a fractional decimation algorithm is applied.
The decimation factor is a multiple of 1/16; values 0 to 15 are forbidden.
| Decimation Value | 0–15 | 16 | 17 | 18 | 19 | ... | 124 | 125 | 126 | 127 |
| Decimation Factor | — | 1 | 1.063 | 1.125 | 1.188 | ... | 7.750 | 7.813 | 7.875 | 7.938 |
| OUTPUT | INPUT | 352 × 288 | 640 × 480 | 800 × 600 | 1280 × 1024 | 1600 × 1200 | 2048 × 1536 |
|---|---|---|---|---|---|---|---|
| VGA 640 × 480 |
F | — | 16 | 20 | 32 | 40 | 51 |
| QVGA 320 × 240 |
F | 16 | 32 | 40 | 64 | 80 | 102 |
| CIF 352 × 288 |
F | 16 | 26 | 33 | 56 | 66 | 85 |
| QCIF 176 × 144 |
F | 32 | 53 | 66 | 113 | 133 | 170 |
Example:
Input 1280 × 1024 Output = 640 × 480
Hratio = 1280/640 = 2
Vratio = 1024/480 = 2.1333
The decimation factor is 2 so 32/16.