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7-2
FFC Function setting
Flat field correction (also called Shading correction) is a function used to improve non-uniform image
arising from imperfections contributed by lens, picture element etc. (Be sure to use FFC function when
using this camera.)
・
Set the shading level to the highest value of video signal.
<Setup steps>
1.
Dark level correction
shade = 0 Turns off shading function
“Resets” the shading gain value remaining in the camera.
shade = 4 Enables shading data entry.
shd-go = 1 Selects the shading gain setting.
shd-dat= 0 Inputs “0” as shading gain value.
shd_set Sets the shading data.
shd_to = N Sets the target gray level of Dark level.
Initial value =6 N : 0 to 255
Then put a cap over the lens.
shade = 6 Starts the shading correction for Dark level.
Completed when “OK” is displayed.
2.
Light level correction
Remove the lens cap and set the target gray level of video level.
Make the level adjustment by changing lens aperture or exposure time using plain white target sample..
(Note: Make the adjustment under the condition that a foreign object is not within the visual field.)
shd_tg = N Sets the target gray level of Light level.
Initial value =150 N : 0 to 255
(Where the Light level should be set at the higher level than that of FFC ”OFF”(at
Dark FFC)
shade = 5 Starts the shading correction for Light level.
Completed when “OK” is displayed.
shd_epsv All shading correction values are stored in EPROM.
Completed when “OK” is displayed.
shade = 1 Turns off shading function
save System settings are stored in EPROM.
Completed when “OK” is displayed.
<Supplementary note>
If the camera gain is changed using “again=N” or “logrl=N”, be sure to make the Dark level correction and
Light level correction once again.
Waveform
before shading
255
0
Waveform
after shading
◆
Dark level (shd-tg) set 8bit
◆
Light level (shd-to) set 8bit