Piv Mode - JAI CV-M2 Operation Manual

6.4.6. PIV mode.

PIV mode (Particle Image Velocimetry) can be used in applications where 2 images should be
taken with a very short time interval. It can only be used with strobe flash as illumination. The
first accumulation time is fixed at 4 µsec. After a delay >1.5 µsec. the second exposure period
starts. It is as long as the time for a full frame. The accumulation is LVAL a-synchronous. The
first exposure period starts at the trigger leading edge. The first strobe flash should be fired
within the first exposure period, and the second strobe flash during the first frame read out
period. The result will then be 2 frames exposed with the flash interval.
To use this mode:
Set function:
Input:
Important notes on using this mode.
•
The duration of the trigger should be >2LVAL to <3FVAL.
•
A new trigger must not be applied before FVAL is low after second frame readout.
• 1LVAL = 47.9 µsec (single). 27.3 µsec (dual).
For horizontal timing refer to 6.2.3. through 6.2.6. (Fig.17. through fig. 20.)
For LVAL a-synchronous accumulation refer to 6.2.8. (fig. 22.)
Ext . Tr i g1
FVAL
LVAL
SUB
SG
Fi r st Exposur e Per i od
4us( 1/ 250, 000s)
EEN
DATA O UT
Ext . Tr i g
LVAL
FVAL
104c k
SUB
SG
Expos ur e del ay :
156c k ( 3. 9us )
Expos ur e
Per i od
EEN
Trigger mode "PIV"
LVAL synchronous accumulation
Scanning format
Output select
Polarity and other functions
Ext. trigger to Camera Link or pin 10 on 12-pin connector.
2 strobe flash
M i n. : 2L
Readout del ay:
1 t o 2L
Second Exposur e Per i od
1 f r am e r ead- out per i od
Fi r st Fr am e
Fig. 28. PIV mode
52ck
40ck ( 1us )
120ck ( 3us )
Fi r st exposur e t i m e:
160c k( 4us)
60c k( 1. 5us )
Fig. 28A. PIV mode details
CV-M2
Second Fr am e
- 23 -
TR=5
LS=1
SC=0 through SC=4
OS=0, OS=1