© National Instruments
|
5-7
NI 17xx Smart Camera User Manual
When strobing is enabled, the smart camera waits until the image readout is complete before
turning on the light for the next frame, as shown in Figure 5-4.
Figure 5-4.
Image Acquisition With Strobing
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 5-3 and 5-4 to calculate the minimum frame period for untriggered
acquisitions with and without strobing.
min frame period
NoStrobeNoTrigger
=
T
+
L
+
E
(5-3)
min frame period
WithStrobeNoTrigger
=
T
+
L
+
E
+
R
(5-4)
Refer to Equations 5-5 and 5-6 to calculate the minimum frame period for triggered acquisitions
with and without strobing.
min frame period
NoStrobeWithTrigger
=
max
(
T
+
L
+
E
, Trigger Delay)
(5-5)
min frame period
WithStrobeWithTrigger
=
max
(
T
+
L
+
E
+
R
, Trigger Delay)
(5-6)
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.
Tables 5-1 and 5-2 list the values for the trigger synchronization variability and the lighting
turn-on time, respectively.
1
Image Readout Completes Before Lighting Strobe Asserts for Next Image
Trigger
Lighting
S
tro
b
e
Expo
su
re
Im
a
ge Re
a
do
u
t
1
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