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8.Features
© 2023 China Daheng Group, Inc. Beijing Image Vision Technology Branch 113
Set ExposureOverlapTimeMax
To optimize the frame rate of the camera, the exposure mode should be set to TriggerWidth:
a)
Set the ExposureMode parameter to TriggerWidth.
b)
Enter a value for the ExposureOverlapTimeMax parameter, which represents the shortest exposure
time the user intends to use (in µs).
Example: Assume that the user wants to trigger the camera to apply exposure times in the range of 3000
µs to 5500 µs, the user needs to set the ExposureOverlapTimeMax parameter of the camera to 3000.
The trigger signal width of the hardware triggering should not be shorter than the value of the
entered ExposureOverlapTimeMax parameter.
8.2.10.2.
Set Exposure Value
Global Shutter
The implementation process of global shutter is as shown in Figure 8-30, all the lines of the sensor are
exposed at the same time, and then the sensor will read out the image date one by one.
The advantage of the global shutter is that all the lines are exposed at the same time, and the images do
not appear offset and distortion when capturing moving objects.
The time width of the flash signal can be got by the following formula:
T
strobe
= T
exposure
Exposure time
Readout
time
All lines are exposing at the same time
All lines transfer electrons from
exposure area to storage area
Reading electrons from
storage area line by line
Time
Figure 8-30 Global shutter
Electronic Rolling Shutter
The implementation process of electronic rolling shutter is as shown in Figure 8-31, different from the
global shutter, electronic rolling shutter exposures from the first line, and starts the second line exposure
after a row period. And so on, after N-1 line, the N line starts exposing. When the first line exposure ends,