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7-3 FFC Function setting
Flat field correction (also called Shading Correction) is a function used to compensate for shading
of an image signal arising from imperfections or inhomogeneities of lens or picture/filter elements .
<Setup steps>
1. Dark level correction
shade=0 <CR> To turn the FFC function off.
To reset the shading gain value stored in the camera.
shade=4 <CR> To permit to enter the shading data.
shd_go=1 <CR> To select the shading gain setting mode
shd_dat=0 <CR> To enter “0”as the shading gain value
shd_set <CR> To set the shading data.
shd_to=N <CR> To set the target Dark level.
Default value = 3 N : 0 to 255
Then put a cap over a lens.
shade = 6 <CR> To start the shading correction for Dark level signal.
Completed when “OK”is displayed.
2. Light level correction
Remove a lens cap and set the target gray level of video signal level.
Take a defocused image of a surface of a plain white paper.
Make the signal level adjustment by changing lens aperture or exposure time.
(Note: Make sure a foreign object does not exist within the visual field.)
shd_tg=N <CR> To set the target Light level.
Default value =150 N : 0 to 255
(Set the target Light level to the level that is higher than the
signal level before Light level correction.)
shade = 5 <CR> To start the shading correction for Light level signal.
Completed when “OK”is displayed.
Then, a flat gray image is obtained.
shd_epsv <CR> To save all shading correction values into EEPROM.
Completed when “OK”is displayed.
shade=1 <CR> To turn the shading correction function on.
save <CR> To save the system settings into EEPROM.
Completed when “OK”is displayed.
