Parameters and Commands
Bonito Technical Manual
V2.2.1
44
Bit group
Value
Function
p
0
PIV mode = Off
p
1
PIV mode = On
PIV means Particle Image Velocimetry.
Exposure control is not available in this mode. The exposure is permanently
active. Thus a synchronized strobe light source and eliminating other light
sources is mandatory.
The frame rate is controlled as usual using parameter F or external trigger, but
note that the camera outputs two images per trigger event.
The strobe light has to be synchronized to the image output of the camera.
This can e.g. be done by an external timing generator which generates a pair
of flash pulses positioned close to each trigger pulse to the camera.
The exposure of the first image ends one line duration (t
L
) after the rising
edge of the incoming trigger signal. Thus the first light pulse should end a few
100 ns before t
L
and the second light pulse should start a few 100 ns after t
L
.
The ideal position and length of this dark guard interval depends on the allow-
able crosstalk of the application and should be tested individually.
If not in continuous mode the time between two rising trigger edges must
exceed 1+2*((
N
+1)+1) line durations.
The trigger high duration should be less than N+1 line durations, but at least
500 ns.
Alternatively the synchronization of light sources can be implemented by
using the corresponding output signal of the camera. For information on syn-
chronization output see
J
in Chapter
Synchronization output (J)
on page 39.
Table 14: Exposure control modes: Exposure timing mode (bit group: p)
