49.5.4.1 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.

Table 49-6. Decimation Factor
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
Table 49-7. Decimation and Scaler Offset Values
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.
Figure 49-5. Resize Examples