LYNX Manual RA02
TRIGGER
DATA
EXPOSURE
STROBE
DATA N-2
DATA N-1
DATA N
DATA N+1
DATA N+2
Exposure N-1
Exposure N
Exposure N+1
Exposure N+2
Exposure N+3
Figure 2.39 - Fast Synchronized Triggering - Rapid Capture
2.5.3
Double Exposure Triggering
Double exposure allows two events (two images) to be captured in rapid
succession using a single trigger pulse. In this mode, the camera idles and
waits for a trigger signal to come from the selected source (the external
connector or CC1). Upon receiving the external trigger signal, the camera
clears the horizontal and vertical registers, sends one 5 microseconds shutter
pulse to clear the pixels, and starts integration. The exposure for the first
frame can be programmed from 1 usec to 65 msec (in 1 microsecond
increments) using the ‘sde’ (Set Double Exposure) command. If CC1 input
is used - the duration of the CC1 trigger pulse can also be used to determine
the first frame exposure. There is a fixed additional delay of 5 usec (because
of the shutter pulse) between the rising edge of the trigger pulse and the
beginning of the integration. Upon receiving the trigger signal the camera
starts integration for the first frame, completes the integration, transfers the
information to the vertical registers and then captures the second image.
While capturing the second image the first one is being read out. After
exposing the second image, the information is transferred to the vertical
registers and read out – Figure 2.40. The second image exposure is equal to
the corresponding camera readout time (frame duration) – refer to section
2.1.4 Timing Diagrams. Along with the shutter pulse the camera sends one
strobe pulse (200 microseconds duration) for synchronization with an
external strobe.
CAUTION NOTE
1.
It is recommended that the minimum time duration between the events
is greater then the vertical transfer pulse duration:
a. 5 microseconds for VGA, 1M48, 2M30, 2M30H and 4M15.
b. 10 microseconds for 11M5.
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