AD-081GE
41
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Exposure Time Abs
(GenICam Standard)
This is a function specified in the GenICam standard.
The shutter speed can be entered as an absolute exposure time in microseconds (μs) in register
address 0xA018. The entered absolute time (Time Abs) is then converted to programmable
exposure (PE) value inside the camera.
The calculating formula below shows the relationship between the PE value used by the camera
for the different readout modes and the value entered in register 0xA018.
Due to round down figure, some discrepancies may occur.
The relation between PE value and Time Abs
Normal readout PE= INT (Exposure time) µs / (1420/33750000)
(Note: INT means round down.)
Note:The minimum value in normal readout is 20µs.
◆
Auto shutter
Auto shutter works in the range of 1/30 to 1/10000 sec depending on the incoming light.
◆
GPIO in combination with Pulse Width trigger
More precise exposure time can be obtained by using GPIO in combination with Pulse Width
mode. The clock generator and counter can be programmed in very fine increments.
For an example of the settings, refer to chapter 8.4.1.
The following table shows the approximate relationship among shutter modes.
Shutter speed (sec)
PE
Exposure Time Aps (µs)
1/50000
0
20
1/16000
1
62
1/10000
2
104
1/4000
5
230
1/2000
11
482
1/1000
23
987
1/500
47
1997
1/250
95
4017
1/120
127
5363
1/100
197
8308
1/60
395
16639
1/30
792
33333
10.3.12 Shading correction
The AD-081GE features a shading correction circuit that can be used for reducing shading
resulting from illumination, lens or prism shading caused
by lenses with a wide output aperture. The shading
correction circuit divides the image into horizontal and
vertical fields, and adjusts these regions in relationship
to the image center. In the internal memory, factory data
is stored. When the shading correction is ON, factory data
is loaded. If it is OFF, the calibration can be activated
and the result can be stored in the user area for reuse.
Each channel is treated separately. The shading
correction works with all pixel formats.
Fig.30 Conceptual drawing for calculating shading correction
