Rainbow Electronics AT91CAP9S250A - Manual (Page 916)

916
6264A–CAP–21-May-07
AT91CAP9S500A/AT91CAP9S250A
45.3.4 Preview Path
45.3.4.1 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 and values 0 to 15 are forbidden.
Example:
Input 1280*1024 Output=640*480
Hratio = 1280/640 =2
Vratio = 1024/480 =2.1333
The decimation factor is 2 so 32/16.
Table 45-6. Decimation Factor
Dec value 0->15 16 17 18 19 ... 124 125 126 127
Dec Factor X 1 1.063 1.125 1.188 ... 7.750 7.813 7.875 7.938
Table 45-7. Decimation and Scaler Offset Values
INPUT
OUTPUT
352*288 640*480 800*600 1280*1024 1600*1200 2048*1536
VGA
640*480
F NA 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 16 53 66 113 133 170