User's Manual

Table Of Contents
S3C2450X RISC MICROPROCESSOR CAMERA INTERFACE
23-27
SourceHsize
TargetHsize_xx
Original Input
Scale Down
SRC_Width = SourceHsize
SRC_Height = SourceVsize
TargetHsize_xx = TargetHsize_Co or TargetHsize_Pr
DST_Width = TargetHsize_xx
DST_Height = TargetVsize_xx
SourceVsize
TargetVsize_xx
SourceHsize
Original Input Zoom In
: WinHorOfst, WinHorOfst2
: WinVerOfst, WinVerOfst2
TargetHsize_xx
TargetHsize_xx = TargetHsize_Co or TargetHsize_Pr
DST_Width = TargetHsize_xx
DST_Height = TargetVsize_xx
SRC_Width = SourceHsize - (WinHorOfst + WinHorOfst2)
SRC_Height = SourceVsize - (WinVerOfst + WinVerOfst2)
SourceVsize
TargetVsize_xx
3
1
4
2
1 2
3 4
Figure 23-17. Scaling scheme
The other control registers of pre-scaled image size, pre-scale ratio, pre-scale shift ratio and main scale ratio are
defined according to the following equations.
If ( SRC_Width >= 64 × DST_Width ) { Exit(-1); /* Out Of Horizontal Scale Range */ }
else if (SRC_Width >= 32 × DST_Width) { PreHorRatio_xx = 32; H_Shift = 5; }
else if (SRC_Width >= 16 × DST_Width) { PreHorRatio_xx = 16; H_Shift = 4; }
else if (SRC_Width >= 8 × DST_Width) { PreHorRatio_xx = 8; H_Shift = 3; }
else if (SRC_Width >= 4 × DST_Width) { PreHorRatio_xx = 4; H_Shift = 2; }
else if (SRC_Width >= 2 × DST_Width) { PreHorRatio_xx = 2; H_Shift = 1; }
else { PreHorRatio_xx = 1; H_Shift = 0; }
PreDstWidth_xx = SRC_Width / PreHorRatio_xx;
MainHorRatio_xx = ( SRC_Width << 8 ) / ( DST_Width << H_Shift);