The Flash Window - Basler acA2040-55 User Manual

AW00123409000
For more information about the flash window output signal, see Section 6.8.2 on
Setting the Shutter Mode
When setting the ShutterMode parameter, make sure the camera is not acquiring
images. Otherwise, the camera might crash.
The cameras have two shutter modes: rolling and global reset release.
You can set the shutter mode from within your application software by using the Basler pylon API.
The following code snippets illustrate using the API to set the shutter modes:
// Set the shutter mode to rolling
camera.ShutterMode.SetValue(ShutterMode_Rolling);
// Set the shutter mode to global reset release
camera.ShutterMode.SetValue(ShutterMode_GlobalResetRelease);
You can also use the Basler pylon Viewer application to easily set the mode.
6.6.2.3

The Flash Window

Flash Window in Rolling Mode
If you are using the rolling mode, capturing images of moving objects requires the use of flash
exposure. If you don't use flash exposure when capturing images of moving objects, the images will
be distorted due to the temporal shift between the start of exposure for each line.
You can avoid distortion problems by using flash lighting and by applying the flash during the "flash
window" for each frame. The flash window is the period of time during a frame acquisition when all
of the lines in the sensor are open for exposure.
Figure 64 illustrates the flash window for the rolling mode.
You can calculate when the flash window opens (i.e., the time from the point where the frame is
triggered until the point where the window opens) using this formula:
Time to Flash Window Open = tRow x (ROI Height -1)
You can calculate the flash window width (i.e., how long the flash window remains open) using this
formula:
Flash Window Width = ExposureTime Parameter Setting - [ (tRow x (ROI Height -1) ]
The tRow values are the same as for both, rolling and global reset release mode and are given in
Table 35 on page 145.
Basler ace USB 3.0
Image Acquisition Control
page 163.
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