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 Value0–1516171819...124125126127
Decimation Factor11.0631.1251.188...7.7507.8137.8757.938
Table 49-7. Decimation and Scaler Offset Values
OUTPUTINPUT352 × 288640 × 480800 × 6001280 × 10241600 × 12002048 × 1536
VGA

640 × 480

F1620324051
QVGA

320 × 240

F1632406480102
CIF

352 × 288

F162633566685
QCIF

176 × 144

F325366113133170
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