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(4-6) Auto gain control function (AGC)
When AGC (Auto Gain Control) function is set to ON, the average value of the output signal is compared to the set reference
level (AGC set value), then the gain value of preamplifier on the stage prior to A/D converter is automatically controlled so that the
reference level and the average output value get equal .
The operating range of AGC is about 20dB.
CCD
S/H
GAIN
Four functions below are limited to use in combination with AGC function.
Note that the combined use of them does not function well.
AEC function
AGC function
[Setup procedure]
● Set FR(15) and FR(14) as follows rewriting FR (Flag register) with serial communication software.
AGCE=FR(15)
AGC function
(Note) "AECE" (Auto Exposure Control Enable) needs to be set to "0"
● Adjust the AGC set value (Reference level) to get necessary luminance level.
(Note) S/N ratio of output signal degrades by using AGC function, in case that the amount of light is insufficient.
(4-7) Auto exposure control (AEC) function
Normal lens ( lens without auto iris function) can have an equal feature with an auto iris lens by using AEC function.
The average value of the output signal is compared to the set reference level (AGC set value), then the exposure time (electronic
shutter time) is automatically controlled so that the reference level and the average output value get equal .
CCD
MGC set value
When AEC function is set to ON, the camera enters Continuous shutter mode and the exposure time changes linearly by 1H
(Horizontal synchronous time) within the range of 1/1000 sec to No shutter.
Four functions below are limited to use in combination with AEC function.
Note that the combined use of them does not function well.
AGC function
AEC function
(Note) When AEC(Auto exposure control) is set to ON in No shutter mode, the camera automatically enters Continuous shutter
mode and the shutter time (exposure time) is automatically controlled in response to luminance.
(Note) When using AEC function, the picture level is subject to hunting phenomenon (phenomenon in which light-dark change
periodically occurs) for the image with the light source of which a brightness fluctuates.
Pream plifier
A/D
AGC set value
Gain control
Block diagram of AG C contr ol cir cuit
Asynchronous shutter
×
×
AECE=FR(14)
1
0
Pream plifier
S/H
A/D
GAIN
AGC set value
Exposure time control
Block diagra m of AEC control circuit
Asynchronous shutter
×
×
Im age output
to GigE I/F
Com pare
COM P
Prolonged exposure
×
Im age output
to GigE I/F
Com pare
COMP
Partial scanning
×
- 11 -
Auto iris lens
×
Prolonged exposure
Auto iris lens
×
M10510B;11/58
×
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