Luminosity/Brightness control can be implemented on OV7670 sensor using their respective registers, as shown bellow.
OV7670 register responsible for this is: 0x56.
Note: High contrast will make picture look sharper, however, will impact the dynamic range.
Contrast +2 (0x56, 0x50) Contrast +1 (0x56, 0x40) Contrast 0 (0x56, 0x50) Contrast -1 (0x56, 0x38) Contrast -2 (0x56, 0x30)
OV7670 register responsible for this is: 0x55.
Note: High brightness will make picture brighter, however, will also make the picture looks “foggy”.
Brightness +2 (0x55, 0x30) Brightness +1 (0x55, 0x18) Brightness 0 (0x55, 0x00) Brightness -1 (0x55, 0x98) Brightness -2 (0x55, 0xb0)