Bonito Technical Manual
V2.4.0
55
Parameters and commands
The camera needs at least one line duration of dead time before it is ready for the
next trigger event, provided the camera is not configured to Continuous mode
(e.g.
M=4
). If the camera is configured to Continuous mode, it needs one addi-
tional line of dead time.
After the second readout from one PIV sequence is complete, the trigger signal‘s
rising edge for the following sequence can be placed only after the minimum
dead time.
and
Table 18: PIV mode timing parameters
independent from other parameters
Example 1
Calculation of the time needed to charge and readout one image pair when the
camera is set to dual channel mode and full frame mode:
•
t
L
= 1.5 μs (1 line duration in dual channel mode)
•
N=6BD
(0x6BD = 1725; default) full frame height of 1726 lines
•
Continuous mode = On
Result: time for one PIV image pair = 2 * ((1726 +1) + 1) * 1.5 μs = 5184 μs,
allowing approx. 192 image pairs per second.
Example 2
Calculation of the time needed to charge and readout one image pair when the
camera is set to single channel mode, but does not work in full frame mode:
•
t
L
= 3.0 μs (1 line duration in single channel mode)
•
N=14A
(0x14A = 330)
•
Continuous mode = Off
Result: time for one PIV image pair = 2 * ((330 +1) + 1) + 1 * 3.0 μs = 1995 μs,
allowing 500 image pairs per second.
Internal charge transfer and readout
The internal charge transfer of the first image starts with a certain fixed delay,
and it takes the time of one line duration (t
L
). The end of the charge transfer ter-
minates the exposure of the first PIV frame and automatically starts the expo-
sure of the second PIV frame.
During each charge transfer, the sensor‘s photo detectors keep integrating the
charge. Even the charge that is newly integrated during the transfer process is
transferred to the sensor‘s pixel memory. A strobe or flash pulse that is fired
during the charge transfer contributes to the image.
Once the charge transfer for the first frame is complete, the new charge, which
integrates within the sensor‘s photo detectors, contributes to the next frame.
Continuous mode
Minimum time necessary
On
2 * ((N+1) + 1) line durations t
L
(the camera is free-running)
Off
2 * ((N+1) + 1) + 1 line durations t
L
Table 16: Minimum time necessary for one PIV image pair (N = number of lines)
