Chapter 6
Image Acquisition
NI 177x Smart Camera User Manual
6-6
ni.com
Use Equation 6-2 to understand how software determines the maximum
frame rate:
(6-2)
where
min frame period
is the minimum amount of time for the strobe
and trigger mode, as described in the
section.
Determining the Exposure Time
The minimum frame period depends on exposure time, lighting mode, and
trigger delay.
A longer exposure time results in a longer frame period, and a slower
maximum frame rate.
Determining the Trigger Delay
If the trigger delay is set longer than the untriggered minimum frame
period, the trigger delay value further limits the
min frame period
. When
the trigger delay is specified in milliseconds, the software includes this in
the calculation of the maximum frame rate indicator.
Calculating the Minimum Frame Period
Refer to Equations 6-3 and 6-4 to calculate the minimum frame period for
untriggered acquisitions with and without strobing.
(6-3)
(6-4)
Refer to Equations 6-5 and 6-6 to calculate the minimum frame period for
triggered acquisitions with and without strobing.
(6-5)
(6-6)
where
T
is the trigger synchronization variability,
L
is the lighting turn-on time,
E
is the exposure time, and
R
is the image readout duration.
max frame rate
1
min frame period
-------------------------------------------
=
min frame period
NoStrobeNoTrigger
T L E
+
+
=
min frame period
WithStrobeNoTrigger
T L E R
+
+
+
=
min frame period
NoStrobeWithTrigger
max T L E
+
+
Trigger Delay
,
(
)
=
min frame period
WithStrobeWithTrigger
max T L E R
+
+
+
Trigger Delay
,
(
)
=
