Data Sheet

10.13.2009 PRODUCT SPECIFICATION proprietary to OmniVision Technologies
5-5
5.6.1 RGB to YUV conversion matrix
The color conversion matrix can be derived from the standard equations below:
Y = 0.59G + 0.31R + 0.11B
U = B - Y
V = R - Y
Cr = 0.713 (R - Y)
Cb = 0.563 (B - Y)
5.7 lens correction (LENC)
The main purpose of the Lens Correction (LENC) function is to compensate for lens imperfection. According to the radius
of each pixel to the lens, the module calculates a gain for the pixel, correcting each pixel with its gain calculated to
compensate for the light distribution due to lens curvature.
Due to the lens roll off, the pixels in the edge and corner area receive much less light than the pixels in the center area,
which makes the image darker in the edges and corner areas. The lens correction function amplifies pixel output based
on the distance from the pixel to the lens optical center to achieve uniform image.
table 5-4 lists lens correction related
registers, and figure 5-2 shows the lens correction function of OV7675/OV7175.
table 5-4 LENC related registers
address register name description
0x55 LCC5
Bit[2]: Lens correction control select
0: R, G, and B channel compensation coefficient is set by
0x64
1: R, G, and B channel compensation coefficient is set by
registers and respectively
Bit[0]: Lens correction enable
0: Disabled
1: Enabled
0x62 LCC1
Lens Correction Option 1
Bit[7]: Sign bit for X coordinate of lens correction center relative to
array center
0: Coordinate is + 0x62[6:0]
1: Coordinate is - 0x62[6:0]
0x63 LCC2
Lens Correction Option 2
Bit[7]: Sign bit for Y coordinate of lens correction center relative to
array center
0: Coordinate is + 0x63[6:0]
1: Coordinate is - 0x63[6:0]
0x65 LCC4 Radius of the circle, no compensation will be applied inside the circle
0x64 LCC3
G Channel Compensation Coefficient when LCC5[2] (0x66) is 1
R, G, and B Channel Compensation Coefficient when LCC5[2] (0x66) is 0
0x94 LCC6 B channel compensation coefficient (effective only when LCC5[2] is high)
0x95 LCC7 R channel compensation coefficient (effective only when LCC5[2] is high)
Simpo PDF Password Remover Unregistered Version - http://www.simpopdf.com